diff --git a/Changelog.md b/Changelog.md
new file mode 100644
--- /dev/null
+++ b/Changelog.md
@@ -0,0 +1,66 @@
+# 0.1.10
+
+- Fix removal of empty lines in free text fields (like `description`)
+  when using `cabal-version: 3.0` (where you can use empty lines)
+
+# 0.1.9
+
+- Change how version ranges with carets are formatted once again.
+  Now `^>=1.2 || ^>=1.3` won't be changed anymore.
+
+# 0.1.8
+
+- Order extensions lexicographically
+
+# 0.1.7
+
+- Use Cabal-syntax-3.10.1.0
+
+# 0.1.6
+
+- Fix filepath issues on Windows
+- Add support for sublibraries
+- Format `build-tool-depends`
+- Use Cabal-syntax-3.8.1.0
+- Smarter version range normaliser
+
+# 0.1.5.1
+
+- Fix bug in pretty printing empty version ranges.
+
+# 0.1.5
+
+- Don't print redundant `-any` in `impl`
+- Add `glob-files` pragma for source file fields (`c-sources`, ...)
+  Glob syntax supports only stars (i.e. no `{}` etc. extras).
+- Source file fields are now sorted
+
+# 0.1.4
+
+- Add `-n` / `--no-cabal-file` to format cabal like, but not package files.
+  Useful to format `cabal.project` or `cabal.haskell-ci`.
+- Add `fragment` pragma to substitute a field or a section with
+  contents of external file.
+  Useful in multi-package setting to keep for example
+  `tested-with` field or `common deps` stanza in sync.
+
+# 0.1.3
+
+- GHC-8.10 support. Require Cabal-3.2
+- Add `--check` operation mode
+
+# 0.1.2
+
+- Don't change current working directories. Don't expand if used on stdin.
+- Sort module names case-insensitively
+
+# 0.1.1
+
+- Change metavar of file arguments to be `FILE...`,
+  to imply that multiple files at once are supported
+- Add `expand src -ModuleName1 -ModuleName2` support
+- Add `--tabular` and `--no-tabular` configuraiton options
+- Add `-Werror` option (there are some warnings)
+- Preserve end file comments
+- More pretty `tested-with` formatting
+- Add `--version` flag
diff --git a/LICENSE.txt b/LICENSE.txt
new file mode 100644
--- /dev/null
+++ b/LICENSE.txt
@@ -0,0 +1,674 @@
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+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Use with the GNU Affero General Public License.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+              END OF TERMS AND CONDITIONS
+
+     How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
diff --git a/cabal-gild.cabal b/cabal-gild.cabal
new file mode 100644
--- /dev/null
+++ b/cabal-gild.cabal
@@ -0,0 +1,119 @@
+cabal-version:      2.2
+name:               cabal-gild
+version:            0.2.0.1
+synopsis:           Format .cabal files
+category:           Development
+description:
+  Format @.cabal@ files preserving the original field ordering, and comments.
+  .
+  Tuned for Oleg's preference, but has some knobs still.
+
+license:            GPL-3.0-or-later AND BSD-3-Clause
+license-file:       LICENSE.txt
+author:             Oleg Grenrus <oleg.grenrus@iki.fi>
+maintainer:         Taylor Fausak
+extra-doc-files:    Changelog.md
+extra-source-files:
+  fixtures/*.cabal
+  fixtures/*.format
+
+source-repository head
+  type:     git
+  location: https://github.com/tfausak/cabal-gild
+
+flag pedantic
+  default: False
+  manual:  True
+
+common library
+  build-depends:    base ^>=4.17.2.1 || ^>=4.18.2.0 || ^>=4.19.0.0
+  default-language: Haskell2010
+  ghc-options:
+    -Weverything -Wno-all-missed-specialisations -Wno-implicit-prelude
+    -Wno-missed-specialisations -Wno-missing-deriving-strategies
+    -Wno-missing-export-lists -Wno-missing-import-lists
+    -Wno-missing-kind-signatures -Wno-missing-safe-haskell-mode
+    -Wno-prepositive-qualified-module -Wno-safe -Wno-unsafe
+
+  if impl(ghc >=9.8)
+    ghc-options: -Wno-missing-role-annotations
+
+  if flag(pedantic)
+    ghc-options: -Werror
+
+common executable
+  import:        library
+  build-depends: cabal-gild
+  ghc-options:   -rtsopts -threaded
+
+library
+  import:          library
+  hs-source-dirs:  source/library
+  other-modules:   Paths_cabal_gild
+  autogen-modules: Paths_cabal_gild
+
+  -- GHC boot libraries
+  build-depends:
+    , bytestring ^>=0.11.5.3 || ^>=0.12.0.2
+    , Cabal-syntax ^>=3.8.1.0 || ^>=3.10.1.0
+    , containers ^>=0.6.7
+    , directory ^>=1.3.7.1
+    , filepath ^>=1.4.2.2
+    , mtl ^>=2.2.2 || ^>=2.3.1
+    , optparse-applicative ^>=0.18.1.0
+    , parsec ^>=3.1.16.1
+    , pretty ^>=1.1.3.6
+
+  -- cabal-gild: expand source/library
+  exposed-modules:
+    CabalGild
+    CabalGild.Comments
+    CabalGild.Error
+    CabalGild.Fields
+    CabalGild.Fields.BuildDepends
+    CabalGild.Fields.Extensions
+    CabalGild.Fields.Modules
+    CabalGild.Fields.SourceFiles
+    CabalGild.Fields.TestedWith
+    CabalGild.FreeText
+    CabalGild.Glob
+    CabalGild.Main
+    CabalGild.Monad
+    CabalGild.Options
+    CabalGild.Parser
+    CabalGild.Pragma
+    CabalGild.Prelude
+    CabalGild.Refactoring
+    CabalGild.Refactoring.ExpandExposedModules
+    CabalGild.Refactoring.Fragments
+    CabalGild.Refactoring.GlobFiles
+    CabalGild.Refactoring.Type
+    VersionInterval
+
+executable cabal-gild
+  import:         executable
+  hs-source-dirs: source/executable
+  main-is:        Main.hs
+
+test-suite cabal-gild-test-suite
+  import:         executable
+  type:           exitcode-stdio-1.0
+  hs-source-dirs: source/test-suite
+  main-is:        Main.hs
+  other-modules:
+    CabalGild.Test.Golden
+    CabalGild.Test.Interval
+
+  -- dependencies in library
+  build-depends:
+    , bytestring
+    , Cabal-syntax
+    , containers
+    , filepath
+    , integer-logarithms ^>=1.0.3.1
+    , QuickCheck ^>=2.14.3
+    , tasty ^>=1.5
+    , tasty-hunit ^>=0.10.1
+    , tasty-quickcheck ^>=0.10.3
+
+-- end file comment
diff --git a/fixtures/Cabal-notab.cabal b/fixtures/Cabal-notab.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/Cabal-notab.cabal
@@ -0,0 +1,653 @@
+name:          Cabal
+version:       2.5.0.0
+-- cabal-gild: no-tabular
+copyright:     2003-2018, Cabal Development Team (see AUTHORS file)
+license:       BSD3
+license-file:  LICENSE
+author:        Cabal Development Team <cabal-devel@haskell.org>
+maintainer:    cabal-devel@haskell.org
+homepage:      http://www.haskell.org/cabal/
+bug-reports:   https://github.com/haskell/cabal/issues
+synopsis:      A framework for packaging Haskell software
+description:
+  The Haskell Common Architecture for Building Applications and
+  Libraries: a framework defining a common interface for authors to more
+  easily build their Haskell applications in a portable way.
+  .
+  The Haskell Cabal is part of a larger infrastructure for distributing,
+  organizing, and cataloging Haskell libraries and tools.
+category:       Distribution
+cabal-version:  >=1.10
+build-type:     Simple
+-- If we use a new Cabal feature, this needs to be changed to Custom so
+-- we can bootstrap.
+
+extra-source-files:
+  README.md tests/README.md ChangeLog.md
+  doc/bugs-and-stability.rst doc/concepts-and-development.rst
+  doc/conf.py doc/config-and-install.rst doc/developing-packages.rst
+  doc/images/Cabal-dark.png doc/index.rst doc/installing-packages.rst
+  doc/intro.rst doc/misc.rst doc/nix-local-build-overview.rst
+  doc/nix-local-build.rst doc/file-format-changelog.rst doc/README.md
+  doc/references.inc
+
+  -- Generated with 'make gen-extra-source-files'
+  -- Do NOT edit this section manually; instead, run the script.
+  -- BEGIN gen-extra-source-files
+  tests/ParserTests/errors/common1.cabal
+  tests/ParserTests/errors/common1.errors
+  tests/ParserTests/errors/common2.cabal
+  tests/ParserTests/errors/common2.errors
+  tests/ParserTests/errors/common3.cabal
+  tests/ParserTests/errors/common3.errors
+  tests/ParserTests/errors/forward-compat.cabal
+  tests/ParserTests/errors/forward-compat.errors
+  tests/ParserTests/errors/forward-compat2.cabal
+  tests/ParserTests/errors/forward-compat2.errors
+  tests/ParserTests/errors/forward-compat3.cabal
+  tests/ParserTests/errors/forward-compat3.errors
+  tests/ParserTests/errors/issue-5055-2.cabal
+  tests/ParserTests/errors/issue-5055-2.errors
+  tests/ParserTests/errors/issue-5055.cabal
+  tests/ParserTests/errors/issue-5055.errors
+  tests/ParserTests/errors/leading-comma-2.cabal
+  tests/ParserTests/errors/leading-comma-2.errors
+  tests/ParserTests/errors/leading-comma-2b.cabal
+  tests/ParserTests/errors/leading-comma-2b.errors
+  tests/ParserTests/errors/leading-comma-2c.cabal
+  tests/ParserTests/errors/leading-comma-2c.errors
+  tests/ParserTests/errors/leading-comma.cabal
+  tests/ParserTests/errors/leading-comma.errors
+  tests/ParserTests/errors/multiple-libs.cabal
+  tests/ParserTests/errors/multiple-libs.errors
+  tests/ParserTests/errors/noVersion.cabal
+  tests/ParserTests/errors/noVersion.errors
+  tests/ParserTests/errors/noVersion2.cabal
+  tests/ParserTests/errors/noVersion2.errors
+  tests/ParserTests/errors/range-ge-wild.cabal
+  tests/ParserTests/errors/range-ge-wild.errors
+  tests/ParserTests/errors/removed-fields.cabal
+  tests/ParserTests/errors/removed-fields.errors
+  tests/ParserTests/errors/spdx-1.cabal
+  tests/ParserTests/errors/spdx-1.errors
+  tests/ParserTests/errors/spdx-2.cabal
+  tests/ParserTests/errors/spdx-2.errors
+  tests/ParserTests/errors/spdx-3.cabal
+  tests/ParserTests/errors/spdx-3.errors
+  tests/ParserTests/ipi/Includes2.cabal
+  tests/ParserTests/ipi/Includes2.expr
+  tests/ParserTests/ipi/Includes2.format
+  tests/ParserTests/ipi/internal-preprocessor-test.cabal
+  tests/ParserTests/ipi/internal-preprocessor-test.expr
+  tests/ParserTests/ipi/internal-preprocessor-test.format
+  tests/ParserTests/ipi/issue-2276-ghc-9885.cabal
+  tests/ParserTests/ipi/issue-2276-ghc-9885.expr
+  tests/ParserTests/ipi/issue-2276-ghc-9885.format
+  tests/ParserTests/ipi/transformers.cabal
+  tests/ParserTests/ipi/transformers.expr
+  tests/ParserTests/ipi/transformers.format
+  tests/ParserTests/regressions/MiniAgda.cabal
+  tests/ParserTests/regressions/MiniAgda.check
+  tests/ParserTests/regressions/Octree-0.5.cabal
+  tests/ParserTests/regressions/Octree-0.5.expr
+  tests/ParserTests/regressions/Octree-0.5.format
+  tests/ParserTests/regressions/bad-glob-syntax.cabal
+  tests/ParserTests/regressions/bad-glob-syntax.check
+  tests/ParserTests/regressions/cc-options-with-optimization.cabal
+  tests/ParserTests/regressions/cc-options-with-optimization.check
+  tests/ParserTests/regressions/common-conditional.cabal
+  tests/ParserTests/regressions/common-conditional.expr
+  tests/ParserTests/regressions/common-conditional.format
+  tests/ParserTests/regressions/common.cabal
+  tests/ParserTests/regressions/common.expr
+  tests/ParserTests/regressions/common.format
+  tests/ParserTests/regressions/common2.cabal
+  tests/ParserTests/regressions/common2.expr
+  tests/ParserTests/regressions/common2.format
+  tests/ParserTests/regressions/cxx-options-with-optimization.cabal
+  tests/ParserTests/regressions/cxx-options-with-optimization.check
+  tests/ParserTests/regressions/elif.cabal
+  tests/ParserTests/regressions/elif.expr
+  tests/ParserTests/regressions/elif.format
+  tests/ParserTests/regressions/elif2.cabal
+  tests/ParserTests/regressions/elif2.expr
+  tests/ParserTests/regressions/elif2.format
+  tests/ParserTests/regressions/encoding-0.8.cabal
+  tests/ParserTests/regressions/encoding-0.8.expr
+  tests/ParserTests/regressions/encoding-0.8.format
+  tests/ParserTests/regressions/extensions-paths-5054.cabal
+  tests/ParserTests/regressions/extensions-paths-5054.check
+  tests/ParserTests/regressions/generics-sop.cabal
+  tests/ParserTests/regressions/generics-sop.expr
+  tests/ParserTests/regressions/generics-sop.format
+  tests/ParserTests/regressions/ghc-option-j.cabal
+  tests/ParserTests/regressions/ghc-option-j.check
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.cabal
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.check
+  tests/ParserTests/regressions/hidden-main-lib.cabal
+  tests/ParserTests/regressions/hidden-main-lib.expr
+  tests/ParserTests/regressions/hidden-main-lib.format
+  tests/ParserTests/regressions/issue-5055.cabal
+  tests/ParserTests/regressions/issue-5055.expr
+  tests/ParserTests/regressions/issue-5055.format
+  tests/ParserTests/regressions/issue-774.cabal
+  tests/ParserTests/regressions/issue-774.check
+  tests/ParserTests/regressions/issue-774.expr
+  tests/ParserTests/regressions/issue-774.format
+  tests/ParserTests/regressions/jaeger-flamegraph.cabal
+  tests/ParserTests/regressions/jaeger-flamegraph.expr
+  tests/ParserTests/regressions/jaeger-flamegraph.format
+  tests/ParserTests/regressions/leading-comma-2.cabal
+  tests/ParserTests/regressions/leading-comma-2.expr
+  tests/ParserTests/regressions/leading-comma-2.format
+  tests/ParserTests/regressions/leading-comma.cabal
+  tests/ParserTests/regressions/leading-comma.expr
+  tests/ParserTests/regressions/leading-comma.format
+  tests/ParserTests/regressions/multiple-libs-2.cabal
+  tests/ParserTests/regressions/multiple-libs-2.check
+  tests/ParserTests/regressions/multiple-libs-2.expr
+  tests/ParserTests/regressions/multiple-libs-2.format
+  tests/ParserTests/regressions/noVersion.cabal
+  tests/ParserTests/regressions/noVersion.expr
+  tests/ParserTests/regressions/noVersion.format
+  tests/ParserTests/regressions/nothing-unicode.cabal
+  tests/ParserTests/regressions/nothing-unicode.check
+  tests/ParserTests/regressions/nothing-unicode.expr
+  tests/ParserTests/regressions/nothing-unicode.format
+  tests/ParserTests/regressions/pre-1.6-glob.cabal
+  tests/ParserTests/regressions/pre-1.6-glob.check
+  tests/ParserTests/regressions/pre-2.4-globstar.cabal
+  tests/ParserTests/regressions/pre-2.4-globstar.check
+  tests/ParserTests/regressions/shake.cabal
+  tests/ParserTests/regressions/shake.expr
+  tests/ParserTests/regressions/shake.format
+  tests/ParserTests/regressions/spdx-1.cabal
+  tests/ParserTests/regressions/spdx-1.expr
+  tests/ParserTests/regressions/spdx-1.format
+  tests/ParserTests/regressions/spdx-2.cabal
+  tests/ParserTests/regressions/spdx-2.expr
+  tests/ParserTests/regressions/spdx-2.format
+  tests/ParserTests/regressions/spdx-3.cabal
+  tests/ParserTests/regressions/spdx-3.expr
+  tests/ParserTests/regressions/spdx-3.format
+  tests/ParserTests/regressions/th-lift-instances.cabal
+  tests/ParserTests/regressions/th-lift-instances.expr
+  tests/ParserTests/regressions/th-lift-instances.format
+  tests/ParserTests/regressions/wl-pprint-indef.cabal
+  tests/ParserTests/regressions/wl-pprint-indef.expr
+  tests/ParserTests/regressions/wl-pprint-indef.format
+  tests/ParserTests/warnings/bom.cabal
+  tests/ParserTests/warnings/bool.cabal
+  tests/ParserTests/warnings/deprecatedfield.cabal
+  tests/ParserTests/warnings/doubledash.cabal
+  tests/ParserTests/warnings/extratestmodule.cabal
+  tests/ParserTests/warnings/gluedop.cabal
+  tests/ParserTests/warnings/multiplesingular.cabal
+  tests/ParserTests/warnings/nbsp.cabal
+  tests/ParserTests/warnings/newsyntax.cabal
+  tests/ParserTests/warnings/oldsyntax.cabal
+  tests/ParserTests/warnings/subsection.cabal
+  tests/ParserTests/warnings/tab.cabal
+  tests/ParserTests/warnings/trailingfield.cabal
+  tests/ParserTests/warnings/unknownfield.cabal
+  tests/ParserTests/warnings/unknownsection.cabal
+  tests/ParserTests/warnings/utf8.cabal
+  tests/ParserTests/warnings/versiontag.cabal
+  tests/hackage/check.sh
+  tests/hackage/download.sh
+  tests/hackage/unpack.sh
+  tests/misc/ghc-supported-languages.hs
+  -- END gen-extra-source-files
+
+source-repository head
+  type:     git
+  location: https://github.com/haskell/cabal/
+  subdir:   Cabal
+
+flag bundled-binary-generic
+  default: False
+
+library
+  build-depends:
+    array      >= 0.4.0.1  && < 0.6,
+    base       >= 4.6      && < 5,
+    bytestring >= 0.10.0.0 && < 0.11,
+    containers >= 0.5.0.0  && < 0.7,
+    deepseq    >= 1.3.0.1  && < 1.5,
+    directory  >= 1.2      && < 1.4,
+    filepath   >= 1.3.0.1  && < 1.5,
+    pretty     >= 1.1.1    && < 1.2,
+    process    >= 1.1.0.2  && < 1.7,
+    time       >= 1.4.0.1  && < 1.10
+
+  if flag(bundled-binary-generic)
+    build-depends: binary >= 0.5.1.1 && < 0.7
+  else
+    build-depends: binary >= 0.7 && < 0.9
+
+  if os(windows)
+    build-depends: Win32 >= 2.3.0.0 && < 2.9
+  else
+    build-depends: unix  >= 2.6.0.0 && < 2.8
+
+  ghc-options: -Wall -fno-ignore-asserts -fwarn-tabs
+  if impl(ghc >= 8.0)
+    ghc-options: -Wcompat -Wnoncanonical-monad-instances
+                 -Wnoncanonical-monadfail-instances
+
+  exposed-modules:
+    Distribution.Backpack
+    Distribution.Backpack.Configure
+    Distribution.Backpack.ComponentsGraph
+    Distribution.Backpack.ConfiguredComponent
+    Distribution.Backpack.DescribeUnitId
+    Distribution.Backpack.FullUnitId
+    Distribution.Backpack.LinkedComponent
+    Distribution.Backpack.ModSubst
+    Distribution.Backpack.ModuleShape
+    Distribution.Backpack.PreModuleShape
+    Distribution.CabalSpecVersion
+    Distribution.Utils.IOData
+    Distribution.Utils.LogProgress
+    Distribution.Utils.MapAccum
+    Distribution.Compat.CreatePipe
+    Distribution.Compat.Directory
+    Distribution.Compat.Environment
+    Distribution.Compat.Exception
+    Distribution.Compat.Graph
+    Distribution.Compat.Internal.TempFile
+    Distribution.Compat.Newtype
+    Distribution.Compat.Prelude.Internal
+    Distribution.Compat.Semigroup
+    Distribution.Compat.Stack
+    Distribution.Compat.Time
+    Distribution.Compat.DList
+    Distribution.Compiler
+    Distribution.InstalledPackageInfo
+    Distribution.Types.AbiDependency
+    Distribution.Types.ExposedModule
+    Distribution.Types.InstalledPackageInfo
+    Distribution.Types.InstalledPackageInfo.FieldGrammar
+    Distribution.License
+    Distribution.Make
+    Distribution.ModuleName
+    Distribution.Package
+    Distribution.PackageDescription
+    Distribution.PackageDescription.Check
+    Distribution.PackageDescription.Configuration
+    Distribution.PackageDescription.PrettyPrint
+    Distribution.PackageDescription.Utils
+    Distribution.ReadE
+    Distribution.Simple
+    Distribution.Simple.Bench
+    Distribution.Simple.Build
+    Distribution.Simple.Build.Macros
+    Distribution.Simple.Build.PathsModule
+    Distribution.Simple.BuildPaths
+    Distribution.Simple.BuildTarget
+    Distribution.Simple.BuildToolDepends
+    Distribution.Simple.CCompiler
+    Distribution.Simple.Command
+    Distribution.Simple.Compiler
+    Distribution.Simple.Configure
+    Distribution.Simple.Flag
+    Distribution.Simple.GHC
+    Distribution.Simple.GHCJS
+    Distribution.Simple.Haddock
+    Distribution.Simple.Doctest
+    Distribution.Simple.Glob
+    Distribution.Simple.HaskellSuite
+    Distribution.Simple.Hpc
+    Distribution.Simple.Install
+    Distribution.Simple.InstallDirs
+    Distribution.Simple.LocalBuildInfo
+    Distribution.Simple.PackageIndex
+    Distribution.Simple.PreProcess
+    Distribution.Simple.PreProcess.Unlit
+    Distribution.Simple.Program
+    Distribution.Simple.Program.Ar
+    Distribution.Simple.Program.Builtin
+    Distribution.Simple.Program.Db
+    Distribution.Simple.Program.Find
+    Distribution.Simple.Program.GHC
+    Distribution.Simple.Program.HcPkg
+    Distribution.Simple.Program.Hpc
+    Distribution.Simple.Program.Internal
+    Distribution.Simple.Program.Ld
+    Distribution.Simple.Program.ResponseFile
+    Distribution.Simple.Program.Run
+    Distribution.Simple.Program.Script
+    Distribution.Simple.Program.Strip
+    Distribution.Simple.Program.Types
+    Distribution.Simple.Register
+    Distribution.Simple.Setup
+    Distribution.Simple.SrcDist
+    Distribution.Simple.Test
+    Distribution.Simple.Test.ExeV10
+    Distribution.Simple.Test.LibV09
+    Distribution.Simple.Test.Log
+    Distribution.Simple.UHC
+    Distribution.Simple.UserHooks
+    Distribution.Simple.Utils
+    Distribution.SPDX
+    Distribution.SPDX.License
+    Distribution.SPDX.LicenseId
+    Distribution.SPDX.LicenseExceptionId
+    Distribution.SPDX.LicenseExpression
+    Distribution.SPDX.LicenseListVersion
+    Distribution.SPDX.LicenseReference
+    Distribution.System
+    Distribution.TestSuite
+    Distribution.Text
+    Distribution.Pretty
+    Distribution.Types.AbiHash
+    Distribution.Types.AnnotatedId
+    Distribution.Types.Benchmark
+    Distribution.Types.BenchmarkInterface
+    Distribution.Types.BenchmarkType
+    Distribution.Types.BuildInfo
+    Distribution.Types.BuildType
+    Distribution.Types.ComponentInclude
+    Distribution.Types.Dependency
+    Distribution.Types.ExeDependency
+    Distribution.Types.LegacyExeDependency
+    Distribution.Types.PkgconfigDependency
+    Distribution.Types.DependencyMap
+    Distribution.Types.ComponentId
+    Distribution.Types.MungedPackageId
+    Distribution.Types.PackageId
+    Distribution.Types.UnitId
+    Distribution.Types.Executable
+    Distribution.Types.ExecutableScope
+    Distribution.Types.Library
+    Distribution.Types.LibraryVisibility
+    Distribution.Types.ForeignLib
+    Distribution.Types.ForeignLibType
+    Distribution.Types.ForeignLibOption
+    Distribution.Types.Module
+    Distribution.Types.ModuleReexport
+    Distribution.Types.ModuleRenaming
+    Distribution.Types.ComponentName
+    Distribution.Types.LibraryName
+    Distribution.Types.MungedPackageName
+    Distribution.Types.PackageName
+    Distribution.Types.PkgconfigName
+    Distribution.Types.UnqualComponentName
+    Distribution.Types.IncludeRenaming
+    Distribution.Types.Mixin
+    Distribution.Types.SetupBuildInfo
+    Distribution.Types.TestSuite
+    Distribution.Types.TestSuiteInterface
+    Distribution.Types.TestType
+    Distribution.Types.GenericPackageDescription
+    Distribution.Types.Condition
+    Distribution.Types.CondTree
+    Distribution.Types.HookedBuildInfo
+    Distribution.Types.PackageDescription
+    Distribution.Types.SourceRepo
+    Distribution.Types.Component
+    Distribution.Types.ComponentLocalBuildInfo
+    Distribution.Types.LocalBuildInfo
+    Distribution.Types.ComponentRequestedSpec
+    Distribution.Types.TargetInfo
+    Distribution.Types.Version
+    Distribution.Types.VersionRange
+    Distribution.Types.VersionInterval
+    Distribution.Types.GivenComponent
+    Distribution.Types.PackageVersionConstraint
+    Distribution.Utils.Generic
+    Distribution.Utils.NubList
+    Distribution.Utils.ShortText
+    Distribution.Utils.Progress
+    Distribution.Verbosity
+    Distribution.Version
+    Language.Haskell.Extension
+    Distribution.Compat.Binary
+
+  -- Parsec parser-related modules
+  build-depends:
+    -- transformers-0.4.0.0 doesn't have record syntax e.g. for Identity
+    -- See also https://github.com/ekmett/transformers-compat/issues/35
+    transformers (>= 0.3      && < 0.4) || (>=0.4.1.0 && <0.6),
+    mtl           >= 2.1      && < 2.3,
+    text          >= 1.2.3.0  && < 1.3,
+    parsec        >= 3.1.13.0 && < 3.2
+  exposed-modules:
+    Distribution.Compat.Parsing
+    Distribution.Compat.CharParsing
+    Distribution.FieldGrammar
+    Distribution.FieldGrammar.Class
+    Distribution.FieldGrammar.FieldDescrs
+    Distribution.FieldGrammar.Parsec
+    Distribution.FieldGrammar.Pretty
+    Distribution.PackageDescription.FieldGrammar
+    Distribution.PackageDescription.Parsec
+    Distribution.PackageDescription.Quirks
+    Distribution.Parsec
+    Distribution.Parsec.Error
+    Distribution.Parsec.Newtypes
+    Distribution.Parsec.Position
+    Distribution.Parsec.Warning
+    Distribution.Parsec.FieldLineStream
+    Distribution.Fields
+    Distribution.Fields.ConfVar
+    Distribution.Fields.Field
+    Distribution.Fields.Lexer
+    Distribution.Fields.LexerMonad
+    Distribution.Fields.ParseResult
+    Distribution.Fields.Parser
+    Distribution.Fields.Pretty
+
+  -- Lens functionality
+  exposed-modules:
+    Distribution.Compat.Lens
+    Distribution.Types.Lens
+    Distribution.Types.Benchmark.Lens
+    Distribution.Types.BuildInfo.Lens
+    Distribution.Types.Executable.Lens
+    Distribution.Types.ForeignLib.Lens
+    Distribution.Types.GenericPackageDescription.Lens
+    Distribution.Types.InstalledPackageInfo.Lens
+    Distribution.Types.Library.Lens
+    Distribution.Types.PackageDescription.Lens
+    Distribution.Types.PackageId.Lens
+    Distribution.Types.SetupBuildInfo.Lens
+    Distribution.Types.SourceRepo.Lens
+    Distribution.Types.TestSuite.Lens
+
+  other-modules:
+    Distribution.Backpack.PreExistingComponent
+    Distribution.Backpack.ReadyComponent
+    Distribution.Backpack.MixLink
+    Distribution.Backpack.ModuleScope
+    Distribution.Backpack.UnifyM
+    Distribution.Backpack.Id
+    Distribution.Utils.UnionFind
+    Distribution.Utils.Base62
+    Distribution.Compat.CopyFile
+    Distribution.Compat.GetShortPathName
+    Distribution.Compat.MonadFail
+    Distribution.Compat.Prelude
+    Distribution.Compat.SnocList
+    Distribution.GetOpt
+    Distribution.Lex
+    Distribution.Utils.String
+    Distribution.Simple.GHC.EnvironmentParser
+    Distribution.Simple.GHC.Internal
+    Distribution.Simple.GHC.ImplInfo
+    Paths_Cabal
+
+  if flag(bundled-binary-generic)
+    other-modules:
+      Distribution.Compat.Binary.Class
+      Distribution.Compat.Binary.Generic
+
+  default-language: Haskell2010
+  other-extensions:
+    BangPatterns
+    CPP
+    DefaultSignatures
+    DeriveDataTypeable
+    DeriveFoldable
+    DeriveFunctor
+    DeriveGeneric
+    DeriveTraversable
+    ExistentialQuantification
+    FlexibleContexts
+    FlexibleInstances
+    GeneralizedNewtypeDeriving
+    ImplicitParams
+    KindSignatures
+    NondecreasingIndentation
+    OverloadedStrings
+    RankNTypes
+    RecordWildCards
+    ScopedTypeVariables
+    StandaloneDeriving
+    Trustworthy
+    TypeFamilies
+    TypeOperators
+    TypeSynonymInstances
+    UndecidableInstances
+
+  if impl(ghc >= 7.11)
+    other-extensions: PatternSynonyms
+
+-- Small, fast running tests.
+test-suite unit-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests
+  other-modules:
+    Test.Laws
+    Test.QuickCheck.Utils
+    UnitTests.Distribution.Compat.CreatePipe
+    UnitTests.Distribution.Compat.Time
+    UnitTests.Distribution.Compat.Graph
+    UnitTests.Distribution.Simple.Glob
+    UnitTests.Distribution.Simple.Program.Internal
+    UnitTests.Distribution.Simple.Utils
+    UnitTests.Distribution.SPDX
+    UnitTests.Distribution.System
+    UnitTests.Distribution.Types.GenericPackageDescription
+    UnitTests.Distribution.Utils.Generic
+    UnitTests.Distribution.Utils.NubList
+    UnitTests.Distribution.Utils.ShortText
+    UnitTests.Distribution.Version
+  main-is: UnitTests.hs
+  build-depends:
+    array,
+    base,
+    bytestring,
+    containers,
+    directory,
+    filepath,
+    integer-logarithms >= 1.0.2 && <1.1,
+    tasty >= 1.1.0.3 && < 1.2,
+    tasty-hunit,
+    tasty-quickcheck,
+    tagged,
+    temporary,
+    text,
+    pretty,
+    QuickCheck >= 2.11.3 && < 2.12,
+    Cabal
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+test-suite parser-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests
+  main-is: ParserTests.hs
+  build-depends:
+    base,
+    base-compat >=0.10.4 && <0.11,
+    bytestring,
+    directory,
+    filepath,
+    tasty >= 1.1.0.3 && < 1.2,
+    tasty-hunit,
+    tasty-quickcheck,
+    tasty-golden >=2.3.1.1 && <2.4,
+    Diff >=0.3.4 && <0.4,
+    Cabal
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+  if impl(ghc >= 7.8)
+    build-depends:
+      tree-diff      >= 0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+test-suite check-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests
+  main-is: CheckTests.hs
+  build-depends:
+    base,
+    bytestring,
+    directory,
+    filepath,
+    tasty >= 1.1.0.3 && < 1.2,
+    tasty-golden >=2.3.1.1 && <2.4,
+    Diff >=0.3.4 && <0.4,
+    Cabal
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+test-suite custom-setup-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests/custom-setup
+  main-is: CustomSetupTests.hs
+  other-modules:
+    CabalDoctestSetup
+    IdrisSetup
+  build-depends:
+    Cabal,
+    base,
+    directory,
+    filepath,
+    process
+  default-language: Haskell2010
+
+test-suite hackage-tests
+  type: exitcode-stdio-1.0
+  main-is: HackageTests.hs
+
+  -- TODO: need to get 01-index.tar on appveyor
+  if os(windows)
+    buildable: False
+
+  hs-source-dirs: tests
+
+  build-depends:
+    base,
+    Cabal,
+    bytestring,
+    deepseq,
+    containers,
+    directory,
+    filepath
+
+  build-depends:
+    base-compat          >=0.10.4   && <0.11,
+    base-orphans         >=0.6      && <0.9,
+    optparse-applicative >=0.13.2.0 && <0.15,
+    stm                  >=2.4.5.0  && <2.6,
+    tar                  >=0.5.0.3  && <0.6
+
+  if impl(ghc >= 7.8)
+    build-depends:
+      tree-diff      >= 0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+  ghc-options: -Wall -rtsopts -threaded
+  default-extensions: CPP
+  default-language: Haskell2010
diff --git a/fixtures/Cabal-notab.format b/fixtures/Cabal-notab.format
new file mode 100644
--- /dev/null
+++ b/fixtures/Cabal-notab.format
@@ -0,0 +1,675 @@
+name:               Cabal
+version:            2.5.0.0
+
+-- cabal-gild: no-tabular
+copyright:          2003-2018, Cabal Development Team (see AUTHORS file)
+license:            BSD3
+license-file:       LICENSE
+author:             Cabal Development Team <cabal-devel@haskell.org>
+maintainer:         cabal-devel@haskell.org
+homepage:           http://www.haskell.org/cabal/
+bug-reports:        https://github.com/haskell/cabal/issues
+synopsis:           A framework for packaging Haskell software
+description:
+  The Haskell Common Architecture for Building Applications and
+  Libraries: a framework defining a common interface for authors to more
+  easily build their Haskell applications in a portable way.
+  .
+  The Haskell Cabal is part of a larger infrastructure for distributing,
+  organizing, and cataloging Haskell libraries and tools.
+
+category:           Distribution
+cabal-version:      >=1.10
+build-type:         Simple
+
+-- If we use a new Cabal feature, this needs to be changed to Custom so
+-- we can bootstrap.
+
+extra-source-files:
+  ChangeLog.md
+  doc/bugs-and-stability.rst
+  doc/concepts-and-development.rst
+  doc/conf.py
+  doc/config-and-install.rst
+  doc/developing-packages.rst
+  doc/file-format-changelog.rst
+  doc/images/Cabal-dark.png
+  doc/index.rst
+  doc/installing-packages.rst
+  doc/intro.rst
+  doc/misc.rst
+  doc/nix-local-build-overview.rst
+  doc/nix-local-build.rst
+  doc/README.md
+  doc/references.inc
+  README.md
+  tests/hackage/check.sh
+  tests/hackage/download.sh
+  tests/hackage/unpack.sh
+  tests/misc/ghc-supported-languages.hs
+  tests/ParserTests/errors/common1.cabal
+  tests/ParserTests/errors/common1.errors
+  tests/ParserTests/errors/common2.cabal
+  tests/ParserTests/errors/common2.errors
+  tests/ParserTests/errors/common3.cabal
+  tests/ParserTests/errors/common3.errors
+  tests/ParserTests/errors/forward-compat.cabal
+  tests/ParserTests/errors/forward-compat.errors
+  tests/ParserTests/errors/forward-compat2.cabal
+  tests/ParserTests/errors/forward-compat2.errors
+  tests/ParserTests/errors/forward-compat3.cabal
+  tests/ParserTests/errors/forward-compat3.errors
+  tests/ParserTests/errors/issue-5055-2.cabal
+  tests/ParserTests/errors/issue-5055-2.errors
+  tests/ParserTests/errors/issue-5055.cabal
+  tests/ParserTests/errors/issue-5055.errors
+  tests/ParserTests/errors/leading-comma-2.cabal
+  tests/ParserTests/errors/leading-comma-2.errors
+  tests/ParserTests/errors/leading-comma-2b.cabal
+  tests/ParserTests/errors/leading-comma-2b.errors
+  tests/ParserTests/errors/leading-comma-2c.cabal
+  tests/ParserTests/errors/leading-comma-2c.errors
+  tests/ParserTests/errors/leading-comma.cabal
+  tests/ParserTests/errors/leading-comma.errors
+  tests/ParserTests/errors/multiple-libs.cabal
+  tests/ParserTests/errors/multiple-libs.errors
+  tests/ParserTests/errors/noVersion.cabal
+  tests/ParserTests/errors/noVersion.errors
+  tests/ParserTests/errors/noVersion2.cabal
+  tests/ParserTests/errors/noVersion2.errors
+  tests/ParserTests/errors/range-ge-wild.cabal
+  tests/ParserTests/errors/range-ge-wild.errors
+  tests/ParserTests/errors/removed-fields.cabal
+  tests/ParserTests/errors/removed-fields.errors
+  tests/ParserTests/errors/spdx-1.cabal
+  tests/ParserTests/errors/spdx-1.errors
+  tests/ParserTests/errors/spdx-2.cabal
+  tests/ParserTests/errors/spdx-2.errors
+  tests/ParserTests/errors/spdx-3.cabal
+  tests/ParserTests/errors/spdx-3.errors
+  tests/ParserTests/ipi/Includes2.cabal
+  tests/ParserTests/ipi/Includes2.expr
+  tests/ParserTests/ipi/Includes2.format
+  tests/ParserTests/ipi/internal-preprocessor-test.cabal
+  tests/ParserTests/ipi/internal-preprocessor-test.expr
+  tests/ParserTests/ipi/internal-preprocessor-test.format
+  tests/ParserTests/ipi/issue-2276-ghc-9885.cabal
+  tests/ParserTests/ipi/issue-2276-ghc-9885.expr
+  tests/ParserTests/ipi/issue-2276-ghc-9885.format
+  tests/ParserTests/ipi/transformers.cabal
+  tests/ParserTests/ipi/transformers.expr
+  tests/ParserTests/ipi/transformers.format
+  tests/ParserTests/regressions/bad-glob-syntax.cabal
+  tests/ParserTests/regressions/bad-glob-syntax.check
+  tests/ParserTests/regressions/cc-options-with-optimization.cabal
+  tests/ParserTests/regressions/cc-options-with-optimization.check
+  tests/ParserTests/regressions/common-conditional.cabal
+  tests/ParserTests/regressions/common-conditional.expr
+  tests/ParserTests/regressions/common-conditional.format
+  tests/ParserTests/regressions/common.cabal
+  tests/ParserTests/regressions/common.expr
+  tests/ParserTests/regressions/common.format
+  tests/ParserTests/regressions/common2.cabal
+  tests/ParserTests/regressions/common2.expr
+  tests/ParserTests/regressions/common2.format
+  tests/ParserTests/regressions/cxx-options-with-optimization.cabal
+  tests/ParserTests/regressions/cxx-options-with-optimization.check
+  tests/ParserTests/regressions/elif.cabal
+  tests/ParserTests/regressions/elif.expr
+  tests/ParserTests/regressions/elif.format
+  tests/ParserTests/regressions/elif2.cabal
+  tests/ParserTests/regressions/elif2.expr
+  tests/ParserTests/regressions/elif2.format
+  tests/ParserTests/regressions/encoding-0.8.cabal
+  tests/ParserTests/regressions/encoding-0.8.expr
+  tests/ParserTests/regressions/encoding-0.8.format
+  tests/ParserTests/regressions/extensions-paths-5054.cabal
+  tests/ParserTests/regressions/extensions-paths-5054.check
+  tests/ParserTests/regressions/generics-sop.cabal
+  tests/ParserTests/regressions/generics-sop.expr
+  tests/ParserTests/regressions/generics-sop.format
+  tests/ParserTests/regressions/ghc-option-j.cabal
+  tests/ParserTests/regressions/ghc-option-j.check
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.cabal
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.check
+  tests/ParserTests/regressions/hidden-main-lib.cabal
+  tests/ParserTests/regressions/hidden-main-lib.expr
+  tests/ParserTests/regressions/hidden-main-lib.format
+  tests/ParserTests/regressions/issue-5055.cabal
+  tests/ParserTests/regressions/issue-5055.expr
+  tests/ParserTests/regressions/issue-5055.format
+  tests/ParserTests/regressions/issue-774.cabal
+  tests/ParserTests/regressions/issue-774.check
+  tests/ParserTests/regressions/issue-774.expr
+  tests/ParserTests/regressions/issue-774.format
+  tests/ParserTests/regressions/jaeger-flamegraph.cabal
+  tests/ParserTests/regressions/jaeger-flamegraph.expr
+  tests/ParserTests/regressions/jaeger-flamegraph.format
+  tests/ParserTests/regressions/leading-comma-2.cabal
+  tests/ParserTests/regressions/leading-comma-2.expr
+  tests/ParserTests/regressions/leading-comma-2.format
+  tests/ParserTests/regressions/leading-comma.cabal
+  tests/ParserTests/regressions/leading-comma.expr
+  tests/ParserTests/regressions/leading-comma.format
+  tests/ParserTests/regressions/MiniAgda.cabal
+  tests/ParserTests/regressions/MiniAgda.check
+  tests/ParserTests/regressions/multiple-libs-2.cabal
+  tests/ParserTests/regressions/multiple-libs-2.check
+  tests/ParserTests/regressions/multiple-libs-2.expr
+  tests/ParserTests/regressions/multiple-libs-2.format
+  tests/ParserTests/regressions/nothing-unicode.cabal
+  tests/ParserTests/regressions/nothing-unicode.check
+  tests/ParserTests/regressions/nothing-unicode.expr
+  tests/ParserTests/regressions/nothing-unicode.format
+  tests/ParserTests/regressions/noVersion.cabal
+  tests/ParserTests/regressions/noVersion.expr
+  tests/ParserTests/regressions/noVersion.format
+  tests/ParserTests/regressions/Octree-0.5.cabal
+  tests/ParserTests/regressions/Octree-0.5.expr
+  tests/ParserTests/regressions/Octree-0.5.format
+  tests/ParserTests/regressions/pre-1.6-glob.cabal
+  tests/ParserTests/regressions/pre-1.6-glob.check
+  tests/ParserTests/regressions/pre-2.4-globstar.cabal
+  tests/ParserTests/regressions/pre-2.4-globstar.check
+  tests/ParserTests/regressions/shake.cabal
+  tests/ParserTests/regressions/shake.expr
+  tests/ParserTests/regressions/shake.format
+  tests/ParserTests/regressions/spdx-1.cabal
+  tests/ParserTests/regressions/spdx-1.expr
+  tests/ParserTests/regressions/spdx-1.format
+  tests/ParserTests/regressions/spdx-2.cabal
+  tests/ParserTests/regressions/spdx-2.expr
+  tests/ParserTests/regressions/spdx-2.format
+  tests/ParserTests/regressions/spdx-3.cabal
+  tests/ParserTests/regressions/spdx-3.expr
+  tests/ParserTests/regressions/spdx-3.format
+  tests/ParserTests/regressions/th-lift-instances.cabal
+  tests/ParserTests/regressions/th-lift-instances.expr
+  tests/ParserTests/regressions/th-lift-instances.format
+  tests/ParserTests/regressions/wl-pprint-indef.cabal
+  tests/ParserTests/regressions/wl-pprint-indef.expr
+  tests/ParserTests/regressions/wl-pprint-indef.format
+  tests/ParserTests/warnings/bom.cabal
+  tests/ParserTests/warnings/bool.cabal
+  tests/ParserTests/warnings/deprecatedfield.cabal
+  tests/ParserTests/warnings/doubledash.cabal
+  tests/ParserTests/warnings/extratestmodule.cabal
+  tests/ParserTests/warnings/gluedop.cabal
+  tests/ParserTests/warnings/multiplesingular.cabal
+  tests/ParserTests/warnings/nbsp.cabal
+  tests/ParserTests/warnings/newsyntax.cabal
+  tests/ParserTests/warnings/oldsyntax.cabal
+  tests/ParserTests/warnings/subsection.cabal
+  tests/ParserTests/warnings/tab.cabal
+  tests/ParserTests/warnings/trailingfield.cabal
+  tests/ParserTests/warnings/unknownfield.cabal
+  tests/ParserTests/warnings/unknownsection.cabal
+  tests/ParserTests/warnings/utf8.cabal
+  tests/ParserTests/warnings/versiontag.cabal
+  tests/README.md
+
+-- Generated with 'make gen-extra-source-files'
+-- Do NOT edit this section manually; instead, run the script.
+-- BEGIN gen-extra-source-files
+-- END gen-extra-source-files
+
+source-repository head
+  type:     git
+  location: https://github.com/haskell/cabal/
+  subdir:   Cabal
+
+flag bundled-binary-generic
+  default: False
+
+library
+  build-depends:
+      array >=0.4.0.1 && <0.6
+    , base >=4.6 && <5
+    , bytestring >=0.10.0.0 && <0.11
+    , containers >=0.5.0.0 && <0.7
+    , deepseq >=1.3.0.1 && <1.5
+    , directory >=1.2 && <1.4
+    , filepath >=1.3.0.1 && <1.5
+    , pretty >=1.1.1 && <1.2
+    , process >=1.1.0.2 && <1.7
+    , time >=1.4.0.1 && <1.10
+
+  if flag(bundled-binary-generic)
+    build-depends: binary >=0.5.1.1 && <0.7
+
+  else
+    build-depends: binary >=0.7 && <0.9
+
+  if os(windows)
+    build-depends: Win32 >=2.3.0.0 && <2.9
+
+  else
+    build-depends: unix >=2.6.0.0 && <2.8
+
+  ghc-options:      -Wall -fno-ignore-asserts -fwarn-tabs
+
+  if impl(ghc >=8.0)
+    ghc-options:
+      -Wcompat -Wnoncanonical-monad-instances
+      -Wnoncanonical-monadfail-instances
+
+  exposed-modules:
+    Distribution.Backpack
+    Distribution.Backpack.ComponentsGraph
+    Distribution.Backpack.Configure
+    Distribution.Backpack.ConfiguredComponent
+    Distribution.Backpack.DescribeUnitId
+    Distribution.Backpack.FullUnitId
+    Distribution.Backpack.LinkedComponent
+    Distribution.Backpack.ModSubst
+    Distribution.Backpack.ModuleShape
+    Distribution.Backpack.PreModuleShape
+    Distribution.CabalSpecVersion
+    Distribution.Compat.Binary
+    Distribution.Compat.CreatePipe
+    Distribution.Compat.Directory
+    Distribution.Compat.DList
+    Distribution.Compat.Environment
+    Distribution.Compat.Exception
+    Distribution.Compat.Graph
+    Distribution.Compat.Internal.TempFile
+    Distribution.Compat.Newtype
+    Distribution.Compat.Prelude.Internal
+    Distribution.Compat.Semigroup
+    Distribution.Compat.Stack
+    Distribution.Compat.Time
+    Distribution.Compiler
+    Distribution.InstalledPackageInfo
+    Distribution.License
+    Distribution.Make
+    Distribution.ModuleName
+    Distribution.Package
+    Distribution.PackageDescription
+    Distribution.PackageDescription.Check
+    Distribution.PackageDescription.Configuration
+    Distribution.PackageDescription.PrettyPrint
+    Distribution.PackageDescription.Utils
+    Distribution.Pretty
+    Distribution.ReadE
+    Distribution.Simple
+    Distribution.Simple.Bench
+    Distribution.Simple.Build
+    Distribution.Simple.Build.Macros
+    Distribution.Simple.Build.PathsModule
+    Distribution.Simple.BuildPaths
+    Distribution.Simple.BuildTarget
+    Distribution.Simple.BuildToolDepends
+    Distribution.Simple.CCompiler
+    Distribution.Simple.Command
+    Distribution.Simple.Compiler
+    Distribution.Simple.Configure
+    Distribution.Simple.Doctest
+    Distribution.Simple.Flag
+    Distribution.Simple.GHC
+    Distribution.Simple.GHCJS
+    Distribution.Simple.Glob
+    Distribution.Simple.Haddock
+    Distribution.Simple.HaskellSuite
+    Distribution.Simple.Hpc
+    Distribution.Simple.Install
+    Distribution.Simple.InstallDirs
+    Distribution.Simple.LocalBuildInfo
+    Distribution.Simple.PackageIndex
+    Distribution.Simple.PreProcess
+    Distribution.Simple.PreProcess.Unlit
+    Distribution.Simple.Program
+    Distribution.Simple.Program.Ar
+    Distribution.Simple.Program.Builtin
+    Distribution.Simple.Program.Db
+    Distribution.Simple.Program.Find
+    Distribution.Simple.Program.GHC
+    Distribution.Simple.Program.HcPkg
+    Distribution.Simple.Program.Hpc
+    Distribution.Simple.Program.Internal
+    Distribution.Simple.Program.Ld
+    Distribution.Simple.Program.ResponseFile
+    Distribution.Simple.Program.Run
+    Distribution.Simple.Program.Script
+    Distribution.Simple.Program.Strip
+    Distribution.Simple.Program.Types
+    Distribution.Simple.Register
+    Distribution.Simple.Setup
+    Distribution.Simple.SrcDist
+    Distribution.Simple.Test
+    Distribution.Simple.Test.ExeV10
+    Distribution.Simple.Test.LibV09
+    Distribution.Simple.Test.Log
+    Distribution.Simple.UHC
+    Distribution.Simple.UserHooks
+    Distribution.Simple.Utils
+    Distribution.SPDX
+    Distribution.SPDX.License
+    Distribution.SPDX.LicenseExceptionId
+    Distribution.SPDX.LicenseExpression
+    Distribution.SPDX.LicenseId
+    Distribution.SPDX.LicenseListVersion
+    Distribution.SPDX.LicenseReference
+    Distribution.System
+    Distribution.TestSuite
+    Distribution.Text
+    Distribution.Types.AbiDependency
+    Distribution.Types.AbiHash
+    Distribution.Types.AnnotatedId
+    Distribution.Types.Benchmark
+    Distribution.Types.BenchmarkInterface
+    Distribution.Types.BenchmarkType
+    Distribution.Types.BuildInfo
+    Distribution.Types.BuildType
+    Distribution.Types.Component
+    Distribution.Types.ComponentId
+    Distribution.Types.ComponentInclude
+    Distribution.Types.ComponentLocalBuildInfo
+    Distribution.Types.ComponentName
+    Distribution.Types.ComponentRequestedSpec
+    Distribution.Types.Condition
+    Distribution.Types.CondTree
+    Distribution.Types.Dependency
+    Distribution.Types.DependencyMap
+    Distribution.Types.Executable
+    Distribution.Types.ExecutableScope
+    Distribution.Types.ExeDependency
+    Distribution.Types.ExposedModule
+    Distribution.Types.ForeignLib
+    Distribution.Types.ForeignLibOption
+    Distribution.Types.ForeignLibType
+    Distribution.Types.GenericPackageDescription
+    Distribution.Types.GivenComponent
+    Distribution.Types.HookedBuildInfo
+    Distribution.Types.IncludeRenaming
+    Distribution.Types.InstalledPackageInfo
+    Distribution.Types.InstalledPackageInfo.FieldGrammar
+    Distribution.Types.LegacyExeDependency
+    Distribution.Types.Library
+    Distribution.Types.LibraryName
+    Distribution.Types.LibraryVisibility
+    Distribution.Types.LocalBuildInfo
+    Distribution.Types.Mixin
+    Distribution.Types.Module
+    Distribution.Types.ModuleReexport
+    Distribution.Types.ModuleRenaming
+    Distribution.Types.MungedPackageId
+    Distribution.Types.MungedPackageName
+    Distribution.Types.PackageDescription
+    Distribution.Types.PackageId
+    Distribution.Types.PackageName
+    Distribution.Types.PackageVersionConstraint
+    Distribution.Types.PkgconfigDependency
+    Distribution.Types.PkgconfigName
+    Distribution.Types.SetupBuildInfo
+    Distribution.Types.SourceRepo
+    Distribution.Types.TargetInfo
+    Distribution.Types.TestSuite
+    Distribution.Types.TestSuiteInterface
+    Distribution.Types.TestType
+    Distribution.Types.UnitId
+    Distribution.Types.UnqualComponentName
+    Distribution.Types.Version
+    Distribution.Types.VersionInterval
+    Distribution.Types.VersionRange
+    Distribution.Utils.Generic
+    Distribution.Utils.IOData
+    Distribution.Utils.LogProgress
+    Distribution.Utils.MapAccum
+    Distribution.Utils.NubList
+    Distribution.Utils.Progress
+    Distribution.Utils.ShortText
+    Distribution.Verbosity
+    Distribution.Version
+    Language.Haskell.Extension
+
+  -- Parsec parser-related modules
+  build-depends:
+      mtl >=2.1 && <2.3
+    , parsec >=3.1.13.0 && <3.2
+    , text >=1.2.3.0 && <1.3
+    , transformers >=0.3 && <0.4 || >=0.4.1.0 && <0.6
+
+  -- transformers-0.4.0.0 doesn't have record syntax e.g. for Identity
+  -- See also https://github.com/ekmett/transformers-compat/issues/35
+  exposed-modules:
+    Distribution.Compat.CharParsing
+    Distribution.Compat.Parsing
+    Distribution.FieldGrammar
+    Distribution.FieldGrammar.Class
+    Distribution.FieldGrammar.FieldDescrs
+    Distribution.FieldGrammar.Parsec
+    Distribution.FieldGrammar.Pretty
+    Distribution.Fields
+    Distribution.Fields.ConfVar
+    Distribution.Fields.Field
+    Distribution.Fields.Lexer
+    Distribution.Fields.LexerMonad
+    Distribution.Fields.Parser
+    Distribution.Fields.ParseResult
+    Distribution.Fields.Pretty
+    Distribution.PackageDescription.FieldGrammar
+    Distribution.PackageDescription.Parsec
+    Distribution.PackageDescription.Quirks
+    Distribution.Parsec
+    Distribution.Parsec.Error
+    Distribution.Parsec.FieldLineStream
+    Distribution.Parsec.Newtypes
+    Distribution.Parsec.Position
+    Distribution.Parsec.Warning
+
+  -- Lens functionality
+  exposed-modules:
+    Distribution.Compat.Lens
+    Distribution.Types.Benchmark.Lens
+    Distribution.Types.BuildInfo.Lens
+    Distribution.Types.Executable.Lens
+    Distribution.Types.ForeignLib.Lens
+    Distribution.Types.GenericPackageDescription.Lens
+    Distribution.Types.InstalledPackageInfo.Lens
+    Distribution.Types.Lens
+    Distribution.Types.Library.Lens
+    Distribution.Types.PackageDescription.Lens
+    Distribution.Types.PackageId.Lens
+    Distribution.Types.SetupBuildInfo.Lens
+    Distribution.Types.SourceRepo.Lens
+    Distribution.Types.TestSuite.Lens
+
+  other-modules:
+    Distribution.Backpack.Id
+    Distribution.Backpack.MixLink
+    Distribution.Backpack.ModuleScope
+    Distribution.Backpack.PreExistingComponent
+    Distribution.Backpack.ReadyComponent
+    Distribution.Backpack.UnifyM
+    Distribution.Compat.CopyFile
+    Distribution.Compat.GetShortPathName
+    Distribution.Compat.MonadFail
+    Distribution.Compat.Prelude
+    Distribution.Compat.SnocList
+    Distribution.GetOpt
+    Distribution.Lex
+    Distribution.Simple.GHC.EnvironmentParser
+    Distribution.Simple.GHC.ImplInfo
+    Distribution.Simple.GHC.Internal
+    Distribution.Utils.Base62
+    Distribution.Utils.String
+    Distribution.Utils.UnionFind
+    Paths_Cabal
+
+  if flag(bundled-binary-generic)
+    other-modules:
+      Distribution.Compat.Binary.Class
+      Distribution.Compat.Binary.Generic
+
+  default-language: Haskell2010
+  other-extensions:
+    BangPatterns
+    CPP
+    DefaultSignatures
+    DeriveDataTypeable
+    DeriveFoldable
+    DeriveFunctor
+    DeriveGeneric
+    DeriveTraversable
+    ExistentialQuantification
+    FlexibleContexts
+    FlexibleInstances
+    GeneralizedNewtypeDeriving
+    ImplicitParams
+    KindSignatures
+    NondecreasingIndentation
+    OverloadedStrings
+    RankNTypes
+    RecordWildCards
+    ScopedTypeVariables
+    StandaloneDeriving
+    Trustworthy
+    TypeFamilies
+    TypeOperators
+    TypeSynonymInstances
+    UndecidableInstances
+
+  if impl(ghc >=7.11)
+    other-extensions: PatternSynonyms
+
+-- Small, fast running tests.
+test-suite unit-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests
+  other-modules:
+    Test.Laws
+    Test.QuickCheck.Utils
+    UnitTests.Distribution.Compat.CreatePipe
+    UnitTests.Distribution.Compat.Graph
+    UnitTests.Distribution.Compat.Time
+    UnitTests.Distribution.Simple.Glob
+    UnitTests.Distribution.Simple.Program.Internal
+    UnitTests.Distribution.Simple.Utils
+    UnitTests.Distribution.SPDX
+    UnitTests.Distribution.System
+    UnitTests.Distribution.Types.GenericPackageDescription
+    UnitTests.Distribution.Utils.Generic
+    UnitTests.Distribution.Utils.NubList
+    UnitTests.Distribution.Utils.ShortText
+    UnitTests.Distribution.Version
+
+  main-is:          UnitTests.hs
+  build-depends:
+      array
+    , base
+    , bytestring
+    , Cabal
+    , containers
+    , directory
+    , filepath
+    , integer-logarithms >=1.0.2 && <1.1
+    , pretty
+    , QuickCheck >=2.11.3 && <2.12
+    , tagged
+    , tasty >=1.1.0.3 && <1.2
+    , tasty-hunit
+    , tasty-quickcheck
+    , temporary
+    , text
+
+  ghc-options:      -Wall
+  default-language: Haskell2010
+
+test-suite parser-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests
+  main-is:          ParserTests.hs
+  build-depends:
+      base
+    , base-compat >=0.10.4 && <0.11
+    , bytestring
+    , Cabal
+    , Diff >=0.3.4 && <0.4
+    , directory
+    , filepath
+    , tasty >=1.1.0.3 && <1.2
+    , tasty-golden >=2.3.1.1 && <2.4
+    , tasty-hunit
+    , tasty-quickcheck
+
+  ghc-options:      -Wall
+  default-language: Haskell2010
+
+  if impl(ghc >=7.8)
+    build-depends: tree-diff >=0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+test-suite check-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests
+  main-is:          CheckTests.hs
+  build-depends:
+      base
+    , bytestring
+    , Cabal
+    , Diff >=0.3.4 && <0.4
+    , directory
+    , filepath
+    , tasty >=1.1.0.3 && <1.2
+    , tasty-golden >=2.3.1.1 && <2.4
+
+  ghc-options:      -Wall
+  default-language: Haskell2010
+
+test-suite custom-setup-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests/custom-setup
+  main-is:          CustomSetupTests.hs
+  other-modules:
+    CabalDoctestSetup
+    IdrisSetup
+
+  build-depends:
+      base
+    , Cabal
+    , directory
+    , filepath
+    , process
+
+  default-language: Haskell2010
+
+test-suite hackage-tests
+  type:               exitcode-stdio-1.0
+  main-is:            HackageTests.hs
+
+  -- TODO: need to get 01-index.tar on appveyor
+  if os(windows)
+    buildable: False
+
+  hs-source-dirs:     tests
+  build-depends:
+      base
+    , bytestring
+    , Cabal
+    , containers
+    , deepseq
+    , directory
+    , filepath
+
+  build-depends:
+      base-compat >=0.10.4 && <0.11
+    , base-orphans >=0.6 && <0.9
+    , optparse-applicative >=0.13.2.0 && <0.15
+    , stm >=2.4.5.0 && <2.6
+    , tar >=0.5.0.3 && <0.6
+
+  if impl(ghc >=7.8)
+    build-depends: tree-diff >=0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+  ghc-options:        -Wall -rtsopts -threaded
+  default-extensions: CPP
+  default-language:   Haskell2010
diff --git a/fixtures/Cabal.cabal b/fixtures/Cabal.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/Cabal.cabal
@@ -0,0 +1,652 @@
+name:          Cabal
+version:       2.5.0.0
+copyright:     2003-2018, Cabal Development Team (see AUTHORS file)
+license:       BSD3
+license-file:  LICENSE
+author:        Cabal Development Team <cabal-devel@haskell.org>
+maintainer:    cabal-devel@haskell.org
+homepage:      http://www.haskell.org/cabal/
+bug-reports:   https://github.com/haskell/cabal/issues
+synopsis:      A framework for packaging Haskell software
+description:
+  The Haskell Common Architecture for Building Applications and
+  Libraries: a framework defining a common interface for authors to more
+  easily build their Haskell applications in a portable way.
+  .
+  The Haskell Cabal is part of a larger infrastructure for distributing,
+  organizing, and cataloging Haskell libraries and tools.
+category:       Distribution
+cabal-version:  >=1.10
+build-type:     Simple
+-- If we use a new Cabal feature, this needs to be changed to Custom so
+-- we can bootstrap.
+
+extra-source-files:
+  README.md tests/README.md ChangeLog.md
+  doc/bugs-and-stability.rst doc/concepts-and-development.rst
+  doc/conf.py doc/config-and-install.rst doc/developing-packages.rst
+  doc/images/Cabal-dark.png doc/index.rst doc/installing-packages.rst
+  doc/intro.rst doc/misc.rst doc/nix-local-build-overview.rst
+  doc/nix-local-build.rst doc/file-format-changelog.rst doc/README.md
+  doc/references.inc
+
+  -- Generated with 'make gen-extra-source-files'
+  -- Do NOT edit this section manually; instead, run the script.
+  -- BEGIN gen-extra-source-files
+  tests/ParserTests/errors/common1.cabal
+  tests/ParserTests/errors/common1.errors
+  tests/ParserTests/errors/common2.cabal
+  tests/ParserTests/errors/common2.errors
+  tests/ParserTests/errors/common3.cabal
+  tests/ParserTests/errors/common3.errors
+  tests/ParserTests/errors/forward-compat.cabal
+  tests/ParserTests/errors/forward-compat.errors
+  tests/ParserTests/errors/forward-compat2.cabal
+  tests/ParserTests/errors/forward-compat2.errors
+  tests/ParserTests/errors/forward-compat3.cabal
+  tests/ParserTests/errors/forward-compat3.errors
+  tests/ParserTests/errors/issue-5055-2.cabal
+  tests/ParserTests/errors/issue-5055-2.errors
+  tests/ParserTests/errors/issue-5055.cabal
+  tests/ParserTests/errors/issue-5055.errors
+  tests/ParserTests/errors/leading-comma-2.cabal
+  tests/ParserTests/errors/leading-comma-2.errors
+  tests/ParserTests/errors/leading-comma-2b.cabal
+  tests/ParserTests/errors/leading-comma-2b.errors
+  tests/ParserTests/errors/leading-comma-2c.cabal
+  tests/ParserTests/errors/leading-comma-2c.errors
+  tests/ParserTests/errors/leading-comma.cabal
+  tests/ParserTests/errors/leading-comma.errors
+  tests/ParserTests/errors/multiple-libs.cabal
+  tests/ParserTests/errors/multiple-libs.errors
+  tests/ParserTests/errors/noVersion.cabal
+  tests/ParserTests/errors/noVersion.errors
+  tests/ParserTests/errors/noVersion2.cabal
+  tests/ParserTests/errors/noVersion2.errors
+  tests/ParserTests/errors/range-ge-wild.cabal
+  tests/ParserTests/errors/range-ge-wild.errors
+  tests/ParserTests/errors/removed-fields.cabal
+  tests/ParserTests/errors/removed-fields.errors
+  tests/ParserTests/errors/spdx-1.cabal
+  tests/ParserTests/errors/spdx-1.errors
+  tests/ParserTests/errors/spdx-2.cabal
+  tests/ParserTests/errors/spdx-2.errors
+  tests/ParserTests/errors/spdx-3.cabal
+  tests/ParserTests/errors/spdx-3.errors
+  tests/ParserTests/ipi/Includes2.cabal
+  tests/ParserTests/ipi/Includes2.expr
+  tests/ParserTests/ipi/Includes2.format
+  tests/ParserTests/ipi/internal-preprocessor-test.cabal
+  tests/ParserTests/ipi/internal-preprocessor-test.expr
+  tests/ParserTests/ipi/internal-preprocessor-test.format
+  tests/ParserTests/ipi/issue-2276-ghc-9885.cabal
+  tests/ParserTests/ipi/issue-2276-ghc-9885.expr
+  tests/ParserTests/ipi/issue-2276-ghc-9885.format
+  tests/ParserTests/ipi/transformers.cabal
+  tests/ParserTests/ipi/transformers.expr
+  tests/ParserTests/ipi/transformers.format
+  tests/ParserTests/regressions/MiniAgda.cabal
+  tests/ParserTests/regressions/MiniAgda.check
+  tests/ParserTests/regressions/Octree-0.5.cabal
+  tests/ParserTests/regressions/Octree-0.5.expr
+  tests/ParserTests/regressions/Octree-0.5.format
+  tests/ParserTests/regressions/bad-glob-syntax.cabal
+  tests/ParserTests/regressions/bad-glob-syntax.check
+  tests/ParserTests/regressions/cc-options-with-optimization.cabal
+  tests/ParserTests/regressions/cc-options-with-optimization.check
+  tests/ParserTests/regressions/common-conditional.cabal
+  tests/ParserTests/regressions/common-conditional.expr
+  tests/ParserTests/regressions/common-conditional.format
+  tests/ParserTests/regressions/common.cabal
+  tests/ParserTests/regressions/common.expr
+  tests/ParserTests/regressions/common.format
+  tests/ParserTests/regressions/common2.cabal
+  tests/ParserTests/regressions/common2.expr
+  tests/ParserTests/regressions/common2.format
+  tests/ParserTests/regressions/cxx-options-with-optimization.cabal
+  tests/ParserTests/regressions/cxx-options-with-optimization.check
+  tests/ParserTests/regressions/elif.cabal
+  tests/ParserTests/regressions/elif.expr
+  tests/ParserTests/regressions/elif.format
+  tests/ParserTests/regressions/elif2.cabal
+  tests/ParserTests/regressions/elif2.expr
+  tests/ParserTests/regressions/elif2.format
+  tests/ParserTests/regressions/encoding-0.8.cabal
+  tests/ParserTests/regressions/encoding-0.8.expr
+  tests/ParserTests/regressions/encoding-0.8.format
+  tests/ParserTests/regressions/extensions-paths-5054.cabal
+  tests/ParserTests/regressions/extensions-paths-5054.check
+  tests/ParserTests/regressions/generics-sop.cabal
+  tests/ParserTests/regressions/generics-sop.expr
+  tests/ParserTests/regressions/generics-sop.format
+  tests/ParserTests/regressions/ghc-option-j.cabal
+  tests/ParserTests/regressions/ghc-option-j.check
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.cabal
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.check
+  tests/ParserTests/regressions/hidden-main-lib.cabal
+  tests/ParserTests/regressions/hidden-main-lib.expr
+  tests/ParserTests/regressions/hidden-main-lib.format
+  tests/ParserTests/regressions/issue-5055.cabal
+  tests/ParserTests/regressions/issue-5055.expr
+  tests/ParserTests/regressions/issue-5055.format
+  tests/ParserTests/regressions/issue-774.cabal
+  tests/ParserTests/regressions/issue-774.check
+  tests/ParserTests/regressions/issue-774.expr
+  tests/ParserTests/regressions/issue-774.format
+  tests/ParserTests/regressions/jaeger-flamegraph.cabal
+  tests/ParserTests/regressions/jaeger-flamegraph.expr
+  tests/ParserTests/regressions/jaeger-flamegraph.format
+  tests/ParserTests/regressions/leading-comma-2.cabal
+  tests/ParserTests/regressions/leading-comma-2.expr
+  tests/ParserTests/regressions/leading-comma-2.format
+  tests/ParserTests/regressions/leading-comma.cabal
+  tests/ParserTests/regressions/leading-comma.expr
+  tests/ParserTests/regressions/leading-comma.format
+  tests/ParserTests/regressions/multiple-libs-2.cabal
+  tests/ParserTests/regressions/multiple-libs-2.check
+  tests/ParserTests/regressions/multiple-libs-2.expr
+  tests/ParserTests/regressions/multiple-libs-2.format
+  tests/ParserTests/regressions/noVersion.cabal
+  tests/ParserTests/regressions/noVersion.expr
+  tests/ParserTests/regressions/noVersion.format
+  tests/ParserTests/regressions/nothing-unicode.cabal
+  tests/ParserTests/regressions/nothing-unicode.check
+  tests/ParserTests/regressions/nothing-unicode.expr
+  tests/ParserTests/regressions/nothing-unicode.format
+  tests/ParserTests/regressions/pre-1.6-glob.cabal
+  tests/ParserTests/regressions/pre-1.6-glob.check
+  tests/ParserTests/regressions/pre-2.4-globstar.cabal
+  tests/ParserTests/regressions/pre-2.4-globstar.check
+  tests/ParserTests/regressions/shake.cabal
+  tests/ParserTests/regressions/shake.expr
+  tests/ParserTests/regressions/shake.format
+  tests/ParserTests/regressions/spdx-1.cabal
+  tests/ParserTests/regressions/spdx-1.expr
+  tests/ParserTests/regressions/spdx-1.format
+  tests/ParserTests/regressions/spdx-2.cabal
+  tests/ParserTests/regressions/spdx-2.expr
+  tests/ParserTests/regressions/spdx-2.format
+  tests/ParserTests/regressions/spdx-3.cabal
+  tests/ParserTests/regressions/spdx-3.expr
+  tests/ParserTests/regressions/spdx-3.format
+  tests/ParserTests/regressions/th-lift-instances.cabal
+  tests/ParserTests/regressions/th-lift-instances.expr
+  tests/ParserTests/regressions/th-lift-instances.format
+  tests/ParserTests/regressions/wl-pprint-indef.cabal
+  tests/ParserTests/regressions/wl-pprint-indef.expr
+  tests/ParserTests/regressions/wl-pprint-indef.format
+  tests/ParserTests/warnings/bom.cabal
+  tests/ParserTests/warnings/bool.cabal
+  tests/ParserTests/warnings/deprecatedfield.cabal
+  tests/ParserTests/warnings/doubledash.cabal
+  tests/ParserTests/warnings/extratestmodule.cabal
+  tests/ParserTests/warnings/gluedop.cabal
+  tests/ParserTests/warnings/multiplesingular.cabal
+  tests/ParserTests/warnings/nbsp.cabal
+  tests/ParserTests/warnings/newsyntax.cabal
+  tests/ParserTests/warnings/oldsyntax.cabal
+  tests/ParserTests/warnings/subsection.cabal
+  tests/ParserTests/warnings/tab.cabal
+  tests/ParserTests/warnings/trailingfield.cabal
+  tests/ParserTests/warnings/unknownfield.cabal
+  tests/ParserTests/warnings/unknownsection.cabal
+  tests/ParserTests/warnings/utf8.cabal
+  tests/ParserTests/warnings/versiontag.cabal
+  tests/hackage/check.sh
+  tests/hackage/download.sh
+  tests/hackage/unpack.sh
+  tests/misc/ghc-supported-languages.hs
+  -- END gen-extra-source-files
+
+source-repository head
+  type:     git
+  location: https://github.com/haskell/cabal/
+  subdir:   Cabal
+
+flag bundled-binary-generic
+  default: False
+
+library
+  build-depends:
+    array      >= 0.4.0.1  && < 0.6,
+    base       >= 4.6      && < 5,
+    bytestring >= 0.10.0.0 && < 0.11,
+    containers >= 0.5.0.0  && < 0.7,
+    deepseq    >= 1.3.0.1  && < 1.5,
+    directory  >= 1.2      && < 1.4,
+    filepath   >= 1.3.0.1  && < 1.5,
+    pretty     >= 1.1.1    && < 1.2,
+    process    >= 1.1.0.2  && < 1.7,
+    time       >= 1.4.0.1  && < 1.10
+
+  if flag(bundled-binary-generic)
+    build-depends: binary >= 0.5.1.1 && < 0.7
+  else
+    build-depends: binary >= 0.7 && < 0.9
+
+  if os(windows)
+    build-depends: Win32 >= 2.3.0.0 && < 2.9
+  else
+    build-depends: unix  >= 2.6.0.0 && < 2.8
+
+  ghc-options: -Wall -fno-ignore-asserts -fwarn-tabs
+  if impl(ghc >= 8.0)
+    ghc-options: -Wcompat -Wnoncanonical-monad-instances
+                 -Wnoncanonical-monadfail-instances
+
+  exposed-modules:
+    Distribution.Backpack
+    Distribution.Backpack.Configure
+    Distribution.Backpack.ComponentsGraph
+    Distribution.Backpack.ConfiguredComponent
+    Distribution.Backpack.DescribeUnitId
+    Distribution.Backpack.FullUnitId
+    Distribution.Backpack.LinkedComponent
+    Distribution.Backpack.ModSubst
+    Distribution.Backpack.ModuleShape
+    Distribution.Backpack.PreModuleShape
+    Distribution.CabalSpecVersion
+    Distribution.Utils.IOData
+    Distribution.Utils.LogProgress
+    Distribution.Utils.MapAccum
+    Distribution.Compat.CreatePipe
+    Distribution.Compat.Directory
+    Distribution.Compat.Environment
+    Distribution.Compat.Exception
+    Distribution.Compat.Graph
+    Distribution.Compat.Internal.TempFile
+    Distribution.Compat.Newtype
+    Distribution.Compat.Prelude.Internal
+    Distribution.Compat.Semigroup
+    Distribution.Compat.Stack
+    Distribution.Compat.Time
+    Distribution.Compat.DList
+    Distribution.Compiler
+    Distribution.InstalledPackageInfo
+    Distribution.Types.AbiDependency
+    Distribution.Types.ExposedModule
+    Distribution.Types.InstalledPackageInfo
+    Distribution.Types.InstalledPackageInfo.FieldGrammar
+    Distribution.License
+    Distribution.Make
+    Distribution.ModuleName
+    Distribution.Package
+    Distribution.PackageDescription
+    Distribution.PackageDescription.Check
+    Distribution.PackageDescription.Configuration
+    Distribution.PackageDescription.PrettyPrint
+    Distribution.PackageDescription.Utils
+    Distribution.ReadE
+    Distribution.Simple
+    Distribution.Simple.Bench
+    Distribution.Simple.Build
+    Distribution.Simple.Build.Macros
+    Distribution.Simple.Build.PathsModule
+    Distribution.Simple.BuildPaths
+    Distribution.Simple.BuildTarget
+    Distribution.Simple.BuildToolDepends
+    Distribution.Simple.CCompiler
+    Distribution.Simple.Command
+    Distribution.Simple.Compiler
+    Distribution.Simple.Configure
+    Distribution.Simple.Flag
+    Distribution.Simple.GHC
+    Distribution.Simple.GHCJS
+    Distribution.Simple.Haddock
+    Distribution.Simple.Doctest
+    Distribution.Simple.Glob
+    Distribution.Simple.HaskellSuite
+    Distribution.Simple.Hpc
+    Distribution.Simple.Install
+    Distribution.Simple.InstallDirs
+    Distribution.Simple.LocalBuildInfo
+    Distribution.Simple.PackageIndex
+    Distribution.Simple.PreProcess
+    Distribution.Simple.PreProcess.Unlit
+    Distribution.Simple.Program
+    Distribution.Simple.Program.Ar
+    Distribution.Simple.Program.Builtin
+    Distribution.Simple.Program.Db
+    Distribution.Simple.Program.Find
+    Distribution.Simple.Program.GHC
+    Distribution.Simple.Program.HcPkg
+    Distribution.Simple.Program.Hpc
+    Distribution.Simple.Program.Internal
+    Distribution.Simple.Program.Ld
+    Distribution.Simple.Program.ResponseFile
+    Distribution.Simple.Program.Run
+    Distribution.Simple.Program.Script
+    Distribution.Simple.Program.Strip
+    Distribution.Simple.Program.Types
+    Distribution.Simple.Register
+    Distribution.Simple.Setup
+    Distribution.Simple.SrcDist
+    Distribution.Simple.Test
+    Distribution.Simple.Test.ExeV10
+    Distribution.Simple.Test.LibV09
+    Distribution.Simple.Test.Log
+    Distribution.Simple.UHC
+    Distribution.Simple.UserHooks
+    Distribution.Simple.Utils
+    Distribution.SPDX
+    Distribution.SPDX.License
+    Distribution.SPDX.LicenseId
+    Distribution.SPDX.LicenseExceptionId
+    Distribution.SPDX.LicenseExpression
+    Distribution.SPDX.LicenseListVersion
+    Distribution.SPDX.LicenseReference
+    Distribution.System
+    Distribution.TestSuite
+    Distribution.Text
+    Distribution.Pretty
+    Distribution.Types.AbiHash
+    Distribution.Types.AnnotatedId
+    Distribution.Types.Benchmark
+    Distribution.Types.BenchmarkInterface
+    Distribution.Types.BenchmarkType
+    Distribution.Types.BuildInfo
+    Distribution.Types.BuildType
+    Distribution.Types.ComponentInclude
+    Distribution.Types.Dependency
+    Distribution.Types.ExeDependency
+    Distribution.Types.LegacyExeDependency
+    Distribution.Types.PkgconfigDependency
+    Distribution.Types.DependencyMap
+    Distribution.Types.ComponentId
+    Distribution.Types.MungedPackageId
+    Distribution.Types.PackageId
+    Distribution.Types.UnitId
+    Distribution.Types.Executable
+    Distribution.Types.ExecutableScope
+    Distribution.Types.Library
+    Distribution.Types.LibraryVisibility
+    Distribution.Types.ForeignLib
+    Distribution.Types.ForeignLibType
+    Distribution.Types.ForeignLibOption
+    Distribution.Types.Module
+    Distribution.Types.ModuleReexport
+    Distribution.Types.ModuleRenaming
+    Distribution.Types.ComponentName
+    Distribution.Types.LibraryName
+    Distribution.Types.MungedPackageName
+    Distribution.Types.PackageName
+    Distribution.Types.PkgconfigName
+    Distribution.Types.UnqualComponentName
+    Distribution.Types.IncludeRenaming
+    Distribution.Types.Mixin
+    Distribution.Types.SetupBuildInfo
+    Distribution.Types.TestSuite
+    Distribution.Types.TestSuiteInterface
+    Distribution.Types.TestType
+    Distribution.Types.GenericPackageDescription
+    Distribution.Types.Condition
+    Distribution.Types.CondTree
+    Distribution.Types.HookedBuildInfo
+    Distribution.Types.PackageDescription
+    Distribution.Types.SourceRepo
+    Distribution.Types.Component
+    Distribution.Types.ComponentLocalBuildInfo
+    Distribution.Types.LocalBuildInfo
+    Distribution.Types.ComponentRequestedSpec
+    Distribution.Types.TargetInfo
+    Distribution.Types.Version
+    Distribution.Types.VersionRange
+    Distribution.Types.VersionInterval
+    Distribution.Types.GivenComponent
+    Distribution.Types.PackageVersionConstraint
+    Distribution.Utils.Generic
+    Distribution.Utils.NubList
+    Distribution.Utils.ShortText
+    Distribution.Utils.Progress
+    Distribution.Verbosity
+    Distribution.Version
+    Language.Haskell.Extension
+    Distribution.Compat.Binary
+
+  -- Parsec parser-related modules
+  build-depends:
+    -- transformers-0.4.0.0 doesn't have record syntax e.g. for Identity
+    -- See also https://github.com/ekmett/transformers-compat/issues/35
+    transformers (>= 0.3      && < 0.4) || (>=0.4.1.0 && <0.6),
+    mtl           >= 2.1      && < 2.3,
+    text          >= 1.2.3.0  && < 1.3,
+    parsec        >= 3.1.13.0 && < 3.2
+  exposed-modules:
+    Distribution.Compat.Parsing
+    Distribution.Compat.CharParsing
+    Distribution.FieldGrammar
+    Distribution.FieldGrammar.Class
+    Distribution.FieldGrammar.FieldDescrs
+    Distribution.FieldGrammar.Parsec
+    Distribution.FieldGrammar.Pretty
+    Distribution.PackageDescription.FieldGrammar
+    Distribution.PackageDescription.Parsec
+    Distribution.PackageDescription.Quirks
+    Distribution.Parsec
+    Distribution.Parsec.Error
+    Distribution.Parsec.Newtypes
+    Distribution.Parsec.Position
+    Distribution.Parsec.Warning
+    Distribution.Parsec.FieldLineStream
+    Distribution.Fields
+    Distribution.Fields.ConfVar
+    Distribution.Fields.Field
+    Distribution.Fields.Lexer
+    Distribution.Fields.LexerMonad
+    Distribution.Fields.ParseResult
+    Distribution.Fields.Parser
+    Distribution.Fields.Pretty
+
+  -- Lens functionality
+  exposed-modules:
+    Distribution.Compat.Lens
+    Distribution.Types.Lens
+    Distribution.Types.Benchmark.Lens
+    Distribution.Types.BuildInfo.Lens
+    Distribution.Types.Executable.Lens
+    Distribution.Types.ForeignLib.Lens
+    Distribution.Types.GenericPackageDescription.Lens
+    Distribution.Types.InstalledPackageInfo.Lens
+    Distribution.Types.Library.Lens
+    Distribution.Types.PackageDescription.Lens
+    Distribution.Types.PackageId.Lens
+    Distribution.Types.SetupBuildInfo.Lens
+    Distribution.Types.SourceRepo.Lens
+    Distribution.Types.TestSuite.Lens
+
+  other-modules:
+    Distribution.Backpack.PreExistingComponent
+    Distribution.Backpack.ReadyComponent
+    Distribution.Backpack.MixLink
+    Distribution.Backpack.ModuleScope
+    Distribution.Backpack.UnifyM
+    Distribution.Backpack.Id
+    Distribution.Utils.UnionFind
+    Distribution.Utils.Base62
+    Distribution.Compat.CopyFile
+    Distribution.Compat.GetShortPathName
+    Distribution.Compat.MonadFail
+    Distribution.Compat.Prelude
+    Distribution.Compat.SnocList
+    Distribution.GetOpt
+    Distribution.Lex
+    Distribution.Utils.String
+    Distribution.Simple.GHC.EnvironmentParser
+    Distribution.Simple.GHC.Internal
+    Distribution.Simple.GHC.ImplInfo
+    Paths_Cabal
+
+  if flag(bundled-binary-generic)
+    other-modules:
+      Distribution.Compat.Binary.Class
+      Distribution.Compat.Binary.Generic
+
+  default-language: Haskell2010
+  other-extensions:
+    BangPatterns
+    CPP
+    DefaultSignatures
+    DeriveDataTypeable
+    DeriveFoldable
+    DeriveFunctor
+    DeriveGeneric
+    DeriveTraversable
+    ExistentialQuantification
+    FlexibleContexts
+    FlexibleInstances
+    GeneralizedNewtypeDeriving
+    ImplicitParams
+    KindSignatures
+    NondecreasingIndentation
+    OverloadedStrings
+    RankNTypes
+    RecordWildCards
+    ScopedTypeVariables
+    StandaloneDeriving
+    Trustworthy
+    TypeFamilies
+    TypeOperators
+    TypeSynonymInstances
+    UndecidableInstances
+
+  if impl(ghc >= 7.11)
+    other-extensions: PatternSynonyms
+
+-- Small, fast running tests.
+test-suite unit-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests
+  other-modules:
+    Test.Laws
+    Test.QuickCheck.Utils
+    UnitTests.Distribution.Compat.CreatePipe
+    UnitTests.Distribution.Compat.Time
+    UnitTests.Distribution.Compat.Graph
+    UnitTests.Distribution.Simple.Glob
+    UnitTests.Distribution.Simple.Program.Internal
+    UnitTests.Distribution.Simple.Utils
+    UnitTests.Distribution.SPDX
+    UnitTests.Distribution.System
+    UnitTests.Distribution.Types.GenericPackageDescription
+    UnitTests.Distribution.Utils.Generic
+    UnitTests.Distribution.Utils.NubList
+    UnitTests.Distribution.Utils.ShortText
+    UnitTests.Distribution.Version
+  main-is: UnitTests.hs
+  build-depends:
+    array,
+    base,
+    bytestring,
+    containers,
+    directory,
+    filepath,
+    integer-logarithms >= 1.0.2 && <1.1,
+    tasty >= 1.1.0.3 && < 1.2,
+    tasty-hunit,
+    tasty-quickcheck,
+    tagged,
+    temporary,
+    text,
+    pretty,
+    QuickCheck >= 2.11.3 && < 2.12,
+    Cabal
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+test-suite parser-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests
+  main-is: ParserTests.hs
+  build-depends:
+    base,
+    base-compat >=0.10.4 && <0.11,
+    bytestring,
+    directory,
+    filepath,
+    tasty >= 1.1.0.3 && < 1.2,
+    tasty-hunit,
+    tasty-quickcheck,
+    tasty-golden >=2.3.1.1 && <2.4,
+    Diff >=0.3.4 && <0.4,
+    Cabal
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+  if impl(ghc >= 7.8)
+    build-depends:
+      tree-diff      >= 0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+test-suite check-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests
+  main-is: CheckTests.hs
+  build-depends:
+    base,
+    bytestring,
+    directory,
+    filepath,
+    tasty >= 1.1.0.3 && < 1.2,
+    tasty-golden >=2.3.1.1 && <2.4,
+    Diff >=0.3.4 && <0.4,
+    Cabal
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+test-suite custom-setup-tests
+  type: exitcode-stdio-1.0
+  hs-source-dirs: tests/custom-setup
+  main-is: CustomSetupTests.hs
+  other-modules:
+    CabalDoctestSetup
+    IdrisSetup
+  build-depends:
+    Cabal,
+    base,
+    directory,
+    filepath,
+    process
+  default-language: Haskell2010
+
+test-suite hackage-tests
+  type: exitcode-stdio-1.0
+  main-is: HackageTests.hs
+
+  -- TODO: need to get 01-index.tar on appveyor
+  if os(windows)
+    buildable: False
+
+  hs-source-dirs: tests
+
+  build-depends:
+    base,
+    Cabal,
+    bytestring,
+    deepseq,
+    containers,
+    directory,
+    filepath
+
+  build-depends:
+    base-compat          >=0.10.4   && <0.11,
+    base-orphans         >=0.6      && <0.9,
+    optparse-applicative >=0.13.2.0 && <0.15,
+    stm                  >=2.4.5.0  && <2.6,
+    tar                  >=0.5.0.3  && <0.6
+
+  if impl(ghc >= 7.8)
+    build-depends:
+      tree-diff      >= 0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+  ghc-options: -Wall -rtsopts -threaded
+  default-extensions: CPP
+  default-language: Haskell2010
diff --git a/fixtures/Cabal.format b/fixtures/Cabal.format
new file mode 100644
--- /dev/null
+++ b/fixtures/Cabal.format
@@ -0,0 +1,673 @@
+name:               Cabal
+version:            2.5.0.0
+copyright:          2003-2018, Cabal Development Team (see AUTHORS file)
+license:            BSD3
+license-file:       LICENSE
+author:             Cabal Development Team <cabal-devel@haskell.org>
+maintainer:         cabal-devel@haskell.org
+homepage:           http://www.haskell.org/cabal/
+bug-reports:        https://github.com/haskell/cabal/issues
+synopsis:           A framework for packaging Haskell software
+description:
+  The Haskell Common Architecture for Building Applications and
+  Libraries: a framework defining a common interface for authors to more
+  easily build their Haskell applications in a portable way.
+  .
+  The Haskell Cabal is part of a larger infrastructure for distributing,
+  organizing, and cataloging Haskell libraries and tools.
+
+category:           Distribution
+cabal-version:      >=1.10
+build-type:         Simple
+
+-- If we use a new Cabal feature, this needs to be changed to Custom so
+-- we can bootstrap.
+
+extra-source-files:
+  ChangeLog.md
+  doc/bugs-and-stability.rst
+  doc/concepts-and-development.rst
+  doc/conf.py
+  doc/config-and-install.rst
+  doc/developing-packages.rst
+  doc/file-format-changelog.rst
+  doc/images/Cabal-dark.png
+  doc/index.rst
+  doc/installing-packages.rst
+  doc/intro.rst
+  doc/misc.rst
+  doc/nix-local-build-overview.rst
+  doc/nix-local-build.rst
+  doc/README.md
+  doc/references.inc
+  README.md
+  tests/hackage/check.sh
+  tests/hackage/download.sh
+  tests/hackage/unpack.sh
+  tests/misc/ghc-supported-languages.hs
+  tests/ParserTests/errors/common1.cabal
+  tests/ParserTests/errors/common1.errors
+  tests/ParserTests/errors/common2.cabal
+  tests/ParserTests/errors/common2.errors
+  tests/ParserTests/errors/common3.cabal
+  tests/ParserTests/errors/common3.errors
+  tests/ParserTests/errors/forward-compat.cabal
+  tests/ParserTests/errors/forward-compat.errors
+  tests/ParserTests/errors/forward-compat2.cabal
+  tests/ParserTests/errors/forward-compat2.errors
+  tests/ParserTests/errors/forward-compat3.cabal
+  tests/ParserTests/errors/forward-compat3.errors
+  tests/ParserTests/errors/issue-5055-2.cabal
+  tests/ParserTests/errors/issue-5055-2.errors
+  tests/ParserTests/errors/issue-5055.cabal
+  tests/ParserTests/errors/issue-5055.errors
+  tests/ParserTests/errors/leading-comma-2.cabal
+  tests/ParserTests/errors/leading-comma-2.errors
+  tests/ParserTests/errors/leading-comma-2b.cabal
+  tests/ParserTests/errors/leading-comma-2b.errors
+  tests/ParserTests/errors/leading-comma-2c.cabal
+  tests/ParserTests/errors/leading-comma-2c.errors
+  tests/ParserTests/errors/leading-comma.cabal
+  tests/ParserTests/errors/leading-comma.errors
+  tests/ParserTests/errors/multiple-libs.cabal
+  tests/ParserTests/errors/multiple-libs.errors
+  tests/ParserTests/errors/noVersion.cabal
+  tests/ParserTests/errors/noVersion.errors
+  tests/ParserTests/errors/noVersion2.cabal
+  tests/ParserTests/errors/noVersion2.errors
+  tests/ParserTests/errors/range-ge-wild.cabal
+  tests/ParserTests/errors/range-ge-wild.errors
+  tests/ParserTests/errors/removed-fields.cabal
+  tests/ParserTests/errors/removed-fields.errors
+  tests/ParserTests/errors/spdx-1.cabal
+  tests/ParserTests/errors/spdx-1.errors
+  tests/ParserTests/errors/spdx-2.cabal
+  tests/ParserTests/errors/spdx-2.errors
+  tests/ParserTests/errors/spdx-3.cabal
+  tests/ParserTests/errors/spdx-3.errors
+  tests/ParserTests/ipi/Includes2.cabal
+  tests/ParserTests/ipi/Includes2.expr
+  tests/ParserTests/ipi/Includes2.format
+  tests/ParserTests/ipi/internal-preprocessor-test.cabal
+  tests/ParserTests/ipi/internal-preprocessor-test.expr
+  tests/ParserTests/ipi/internal-preprocessor-test.format
+  tests/ParserTests/ipi/issue-2276-ghc-9885.cabal
+  tests/ParserTests/ipi/issue-2276-ghc-9885.expr
+  tests/ParserTests/ipi/issue-2276-ghc-9885.format
+  tests/ParserTests/ipi/transformers.cabal
+  tests/ParserTests/ipi/transformers.expr
+  tests/ParserTests/ipi/transformers.format
+  tests/ParserTests/regressions/bad-glob-syntax.cabal
+  tests/ParserTests/regressions/bad-glob-syntax.check
+  tests/ParserTests/regressions/cc-options-with-optimization.cabal
+  tests/ParserTests/regressions/cc-options-with-optimization.check
+  tests/ParserTests/regressions/common-conditional.cabal
+  tests/ParserTests/regressions/common-conditional.expr
+  tests/ParserTests/regressions/common-conditional.format
+  tests/ParserTests/regressions/common.cabal
+  tests/ParserTests/regressions/common.expr
+  tests/ParserTests/regressions/common.format
+  tests/ParserTests/regressions/common2.cabal
+  tests/ParserTests/regressions/common2.expr
+  tests/ParserTests/regressions/common2.format
+  tests/ParserTests/regressions/cxx-options-with-optimization.cabal
+  tests/ParserTests/regressions/cxx-options-with-optimization.check
+  tests/ParserTests/regressions/elif.cabal
+  tests/ParserTests/regressions/elif.expr
+  tests/ParserTests/regressions/elif.format
+  tests/ParserTests/regressions/elif2.cabal
+  tests/ParserTests/regressions/elif2.expr
+  tests/ParserTests/regressions/elif2.format
+  tests/ParserTests/regressions/encoding-0.8.cabal
+  tests/ParserTests/regressions/encoding-0.8.expr
+  tests/ParserTests/regressions/encoding-0.8.format
+  tests/ParserTests/regressions/extensions-paths-5054.cabal
+  tests/ParserTests/regressions/extensions-paths-5054.check
+  tests/ParserTests/regressions/generics-sop.cabal
+  tests/ParserTests/regressions/generics-sop.expr
+  tests/ParserTests/regressions/generics-sop.format
+  tests/ParserTests/regressions/ghc-option-j.cabal
+  tests/ParserTests/regressions/ghc-option-j.check
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.cabal
+  tests/ParserTests/regressions/haddock-api-2.18.1-check.check
+  tests/ParserTests/regressions/hidden-main-lib.cabal
+  tests/ParserTests/regressions/hidden-main-lib.expr
+  tests/ParserTests/regressions/hidden-main-lib.format
+  tests/ParserTests/regressions/issue-5055.cabal
+  tests/ParserTests/regressions/issue-5055.expr
+  tests/ParserTests/regressions/issue-5055.format
+  tests/ParserTests/regressions/issue-774.cabal
+  tests/ParserTests/regressions/issue-774.check
+  tests/ParserTests/regressions/issue-774.expr
+  tests/ParserTests/regressions/issue-774.format
+  tests/ParserTests/regressions/jaeger-flamegraph.cabal
+  tests/ParserTests/regressions/jaeger-flamegraph.expr
+  tests/ParserTests/regressions/jaeger-flamegraph.format
+  tests/ParserTests/regressions/leading-comma-2.cabal
+  tests/ParserTests/regressions/leading-comma-2.expr
+  tests/ParserTests/regressions/leading-comma-2.format
+  tests/ParserTests/regressions/leading-comma.cabal
+  tests/ParserTests/regressions/leading-comma.expr
+  tests/ParserTests/regressions/leading-comma.format
+  tests/ParserTests/regressions/MiniAgda.cabal
+  tests/ParserTests/regressions/MiniAgda.check
+  tests/ParserTests/regressions/multiple-libs-2.cabal
+  tests/ParserTests/regressions/multiple-libs-2.check
+  tests/ParserTests/regressions/multiple-libs-2.expr
+  tests/ParserTests/regressions/multiple-libs-2.format
+  tests/ParserTests/regressions/nothing-unicode.cabal
+  tests/ParserTests/regressions/nothing-unicode.check
+  tests/ParserTests/regressions/nothing-unicode.expr
+  tests/ParserTests/regressions/nothing-unicode.format
+  tests/ParserTests/regressions/noVersion.cabal
+  tests/ParserTests/regressions/noVersion.expr
+  tests/ParserTests/regressions/noVersion.format
+  tests/ParserTests/regressions/Octree-0.5.cabal
+  tests/ParserTests/regressions/Octree-0.5.expr
+  tests/ParserTests/regressions/Octree-0.5.format
+  tests/ParserTests/regressions/pre-1.6-glob.cabal
+  tests/ParserTests/regressions/pre-1.6-glob.check
+  tests/ParserTests/regressions/pre-2.4-globstar.cabal
+  tests/ParserTests/regressions/pre-2.4-globstar.check
+  tests/ParserTests/regressions/shake.cabal
+  tests/ParserTests/regressions/shake.expr
+  tests/ParserTests/regressions/shake.format
+  tests/ParserTests/regressions/spdx-1.cabal
+  tests/ParserTests/regressions/spdx-1.expr
+  tests/ParserTests/regressions/spdx-1.format
+  tests/ParserTests/regressions/spdx-2.cabal
+  tests/ParserTests/regressions/spdx-2.expr
+  tests/ParserTests/regressions/spdx-2.format
+  tests/ParserTests/regressions/spdx-3.cabal
+  tests/ParserTests/regressions/spdx-3.expr
+  tests/ParserTests/regressions/spdx-3.format
+  tests/ParserTests/regressions/th-lift-instances.cabal
+  tests/ParserTests/regressions/th-lift-instances.expr
+  tests/ParserTests/regressions/th-lift-instances.format
+  tests/ParserTests/regressions/wl-pprint-indef.cabal
+  tests/ParserTests/regressions/wl-pprint-indef.expr
+  tests/ParserTests/regressions/wl-pprint-indef.format
+  tests/ParserTests/warnings/bom.cabal
+  tests/ParserTests/warnings/bool.cabal
+  tests/ParserTests/warnings/deprecatedfield.cabal
+  tests/ParserTests/warnings/doubledash.cabal
+  tests/ParserTests/warnings/extratestmodule.cabal
+  tests/ParserTests/warnings/gluedop.cabal
+  tests/ParserTests/warnings/multiplesingular.cabal
+  tests/ParserTests/warnings/nbsp.cabal
+  tests/ParserTests/warnings/newsyntax.cabal
+  tests/ParserTests/warnings/oldsyntax.cabal
+  tests/ParserTests/warnings/subsection.cabal
+  tests/ParserTests/warnings/tab.cabal
+  tests/ParserTests/warnings/trailingfield.cabal
+  tests/ParserTests/warnings/unknownfield.cabal
+  tests/ParserTests/warnings/unknownsection.cabal
+  tests/ParserTests/warnings/utf8.cabal
+  tests/ParserTests/warnings/versiontag.cabal
+  tests/README.md
+
+-- Generated with 'make gen-extra-source-files'
+-- Do NOT edit this section manually; instead, run the script.
+-- BEGIN gen-extra-source-files
+-- END gen-extra-source-files
+
+source-repository head
+  type:     git
+  location: https://github.com/haskell/cabal/
+  subdir:   Cabal
+
+flag bundled-binary-generic
+  default: False
+
+library
+  build-depends:
+      array       >=0.4.0.1  && <0.6
+    , base        >=4.6      && <5
+    , bytestring  >=0.10.0.0 && <0.11
+    , containers  >=0.5.0.0  && <0.7
+    , deepseq     >=1.3.0.1  && <1.5
+    , directory   >=1.2      && <1.4
+    , filepath    >=1.3.0.1  && <1.5
+    , pretty      >=1.1.1    && <1.2
+    , process     >=1.1.0.2  && <1.7
+    , time        >=1.4.0.1  && <1.10
+
+  if flag(bundled-binary-generic)
+    build-depends: binary >=0.5.1.1 && <0.7
+
+  else
+    build-depends: binary >=0.7 && <0.9
+
+  if os(windows)
+    build-depends: Win32 >=2.3.0.0 && <2.9
+
+  else
+    build-depends: unix >=2.6.0.0 && <2.8
+
+  ghc-options:      -Wall -fno-ignore-asserts -fwarn-tabs
+
+  if impl(ghc >=8.0)
+    ghc-options:
+      -Wcompat -Wnoncanonical-monad-instances
+      -Wnoncanonical-monadfail-instances
+
+  exposed-modules:
+    Distribution.Backpack
+    Distribution.Backpack.ComponentsGraph
+    Distribution.Backpack.Configure
+    Distribution.Backpack.ConfiguredComponent
+    Distribution.Backpack.DescribeUnitId
+    Distribution.Backpack.FullUnitId
+    Distribution.Backpack.LinkedComponent
+    Distribution.Backpack.ModSubst
+    Distribution.Backpack.ModuleShape
+    Distribution.Backpack.PreModuleShape
+    Distribution.CabalSpecVersion
+    Distribution.Compat.Binary
+    Distribution.Compat.CreatePipe
+    Distribution.Compat.Directory
+    Distribution.Compat.DList
+    Distribution.Compat.Environment
+    Distribution.Compat.Exception
+    Distribution.Compat.Graph
+    Distribution.Compat.Internal.TempFile
+    Distribution.Compat.Newtype
+    Distribution.Compat.Prelude.Internal
+    Distribution.Compat.Semigroup
+    Distribution.Compat.Stack
+    Distribution.Compat.Time
+    Distribution.Compiler
+    Distribution.InstalledPackageInfo
+    Distribution.License
+    Distribution.Make
+    Distribution.ModuleName
+    Distribution.Package
+    Distribution.PackageDescription
+    Distribution.PackageDescription.Check
+    Distribution.PackageDescription.Configuration
+    Distribution.PackageDescription.PrettyPrint
+    Distribution.PackageDescription.Utils
+    Distribution.Pretty
+    Distribution.ReadE
+    Distribution.Simple
+    Distribution.Simple.Bench
+    Distribution.Simple.Build
+    Distribution.Simple.Build.Macros
+    Distribution.Simple.Build.PathsModule
+    Distribution.Simple.BuildPaths
+    Distribution.Simple.BuildTarget
+    Distribution.Simple.BuildToolDepends
+    Distribution.Simple.CCompiler
+    Distribution.Simple.Command
+    Distribution.Simple.Compiler
+    Distribution.Simple.Configure
+    Distribution.Simple.Doctest
+    Distribution.Simple.Flag
+    Distribution.Simple.GHC
+    Distribution.Simple.GHCJS
+    Distribution.Simple.Glob
+    Distribution.Simple.Haddock
+    Distribution.Simple.HaskellSuite
+    Distribution.Simple.Hpc
+    Distribution.Simple.Install
+    Distribution.Simple.InstallDirs
+    Distribution.Simple.LocalBuildInfo
+    Distribution.Simple.PackageIndex
+    Distribution.Simple.PreProcess
+    Distribution.Simple.PreProcess.Unlit
+    Distribution.Simple.Program
+    Distribution.Simple.Program.Ar
+    Distribution.Simple.Program.Builtin
+    Distribution.Simple.Program.Db
+    Distribution.Simple.Program.Find
+    Distribution.Simple.Program.GHC
+    Distribution.Simple.Program.HcPkg
+    Distribution.Simple.Program.Hpc
+    Distribution.Simple.Program.Internal
+    Distribution.Simple.Program.Ld
+    Distribution.Simple.Program.ResponseFile
+    Distribution.Simple.Program.Run
+    Distribution.Simple.Program.Script
+    Distribution.Simple.Program.Strip
+    Distribution.Simple.Program.Types
+    Distribution.Simple.Register
+    Distribution.Simple.Setup
+    Distribution.Simple.SrcDist
+    Distribution.Simple.Test
+    Distribution.Simple.Test.ExeV10
+    Distribution.Simple.Test.LibV09
+    Distribution.Simple.Test.Log
+    Distribution.Simple.UHC
+    Distribution.Simple.UserHooks
+    Distribution.Simple.Utils
+    Distribution.SPDX
+    Distribution.SPDX.License
+    Distribution.SPDX.LicenseExceptionId
+    Distribution.SPDX.LicenseExpression
+    Distribution.SPDX.LicenseId
+    Distribution.SPDX.LicenseListVersion
+    Distribution.SPDX.LicenseReference
+    Distribution.System
+    Distribution.TestSuite
+    Distribution.Text
+    Distribution.Types.AbiDependency
+    Distribution.Types.AbiHash
+    Distribution.Types.AnnotatedId
+    Distribution.Types.Benchmark
+    Distribution.Types.BenchmarkInterface
+    Distribution.Types.BenchmarkType
+    Distribution.Types.BuildInfo
+    Distribution.Types.BuildType
+    Distribution.Types.Component
+    Distribution.Types.ComponentId
+    Distribution.Types.ComponentInclude
+    Distribution.Types.ComponentLocalBuildInfo
+    Distribution.Types.ComponentName
+    Distribution.Types.ComponentRequestedSpec
+    Distribution.Types.Condition
+    Distribution.Types.CondTree
+    Distribution.Types.Dependency
+    Distribution.Types.DependencyMap
+    Distribution.Types.Executable
+    Distribution.Types.ExecutableScope
+    Distribution.Types.ExeDependency
+    Distribution.Types.ExposedModule
+    Distribution.Types.ForeignLib
+    Distribution.Types.ForeignLibOption
+    Distribution.Types.ForeignLibType
+    Distribution.Types.GenericPackageDescription
+    Distribution.Types.GivenComponent
+    Distribution.Types.HookedBuildInfo
+    Distribution.Types.IncludeRenaming
+    Distribution.Types.InstalledPackageInfo
+    Distribution.Types.InstalledPackageInfo.FieldGrammar
+    Distribution.Types.LegacyExeDependency
+    Distribution.Types.Library
+    Distribution.Types.LibraryName
+    Distribution.Types.LibraryVisibility
+    Distribution.Types.LocalBuildInfo
+    Distribution.Types.Mixin
+    Distribution.Types.Module
+    Distribution.Types.ModuleReexport
+    Distribution.Types.ModuleRenaming
+    Distribution.Types.MungedPackageId
+    Distribution.Types.MungedPackageName
+    Distribution.Types.PackageDescription
+    Distribution.Types.PackageId
+    Distribution.Types.PackageName
+    Distribution.Types.PackageVersionConstraint
+    Distribution.Types.PkgconfigDependency
+    Distribution.Types.PkgconfigName
+    Distribution.Types.SetupBuildInfo
+    Distribution.Types.SourceRepo
+    Distribution.Types.TargetInfo
+    Distribution.Types.TestSuite
+    Distribution.Types.TestSuiteInterface
+    Distribution.Types.TestType
+    Distribution.Types.UnitId
+    Distribution.Types.UnqualComponentName
+    Distribution.Types.Version
+    Distribution.Types.VersionInterval
+    Distribution.Types.VersionRange
+    Distribution.Utils.Generic
+    Distribution.Utils.IOData
+    Distribution.Utils.LogProgress
+    Distribution.Utils.MapAccum
+    Distribution.Utils.NubList
+    Distribution.Utils.Progress
+    Distribution.Utils.ShortText
+    Distribution.Verbosity
+    Distribution.Version
+    Language.Haskell.Extension
+
+  -- Parsec parser-related modules
+  build-depends:
+      mtl           >=2.1      && <2.3
+    , parsec        >=3.1.13.0 && <3.2
+    , text          >=1.2.3.0  && <1.3
+    , transformers  >=0.3      && <0.4 || >=0.4.1.0 && <0.6
+
+  -- transformers-0.4.0.0 doesn't have record syntax e.g. for Identity
+  -- See also https://github.com/ekmett/transformers-compat/issues/35
+  exposed-modules:
+    Distribution.Compat.CharParsing
+    Distribution.Compat.Parsing
+    Distribution.FieldGrammar
+    Distribution.FieldGrammar.Class
+    Distribution.FieldGrammar.FieldDescrs
+    Distribution.FieldGrammar.Parsec
+    Distribution.FieldGrammar.Pretty
+    Distribution.Fields
+    Distribution.Fields.ConfVar
+    Distribution.Fields.Field
+    Distribution.Fields.Lexer
+    Distribution.Fields.LexerMonad
+    Distribution.Fields.Parser
+    Distribution.Fields.ParseResult
+    Distribution.Fields.Pretty
+    Distribution.PackageDescription.FieldGrammar
+    Distribution.PackageDescription.Parsec
+    Distribution.PackageDescription.Quirks
+    Distribution.Parsec
+    Distribution.Parsec.Error
+    Distribution.Parsec.FieldLineStream
+    Distribution.Parsec.Newtypes
+    Distribution.Parsec.Position
+    Distribution.Parsec.Warning
+
+  -- Lens functionality
+  exposed-modules:
+    Distribution.Compat.Lens
+    Distribution.Types.Benchmark.Lens
+    Distribution.Types.BuildInfo.Lens
+    Distribution.Types.Executable.Lens
+    Distribution.Types.ForeignLib.Lens
+    Distribution.Types.GenericPackageDescription.Lens
+    Distribution.Types.InstalledPackageInfo.Lens
+    Distribution.Types.Lens
+    Distribution.Types.Library.Lens
+    Distribution.Types.PackageDescription.Lens
+    Distribution.Types.PackageId.Lens
+    Distribution.Types.SetupBuildInfo.Lens
+    Distribution.Types.SourceRepo.Lens
+    Distribution.Types.TestSuite.Lens
+
+  other-modules:
+    Distribution.Backpack.Id
+    Distribution.Backpack.MixLink
+    Distribution.Backpack.ModuleScope
+    Distribution.Backpack.PreExistingComponent
+    Distribution.Backpack.ReadyComponent
+    Distribution.Backpack.UnifyM
+    Distribution.Compat.CopyFile
+    Distribution.Compat.GetShortPathName
+    Distribution.Compat.MonadFail
+    Distribution.Compat.Prelude
+    Distribution.Compat.SnocList
+    Distribution.GetOpt
+    Distribution.Lex
+    Distribution.Simple.GHC.EnvironmentParser
+    Distribution.Simple.GHC.ImplInfo
+    Distribution.Simple.GHC.Internal
+    Distribution.Utils.Base62
+    Distribution.Utils.String
+    Distribution.Utils.UnionFind
+    Paths_Cabal
+
+  if flag(bundled-binary-generic)
+    other-modules:
+      Distribution.Compat.Binary.Class
+      Distribution.Compat.Binary.Generic
+
+  default-language: Haskell2010
+  other-extensions:
+    BangPatterns
+    CPP
+    DefaultSignatures
+    DeriveDataTypeable
+    DeriveFoldable
+    DeriveFunctor
+    DeriveGeneric
+    DeriveTraversable
+    ExistentialQuantification
+    FlexibleContexts
+    FlexibleInstances
+    GeneralizedNewtypeDeriving
+    ImplicitParams
+    KindSignatures
+    NondecreasingIndentation
+    OverloadedStrings
+    RankNTypes
+    RecordWildCards
+    ScopedTypeVariables
+    StandaloneDeriving
+    Trustworthy
+    TypeFamilies
+    TypeOperators
+    TypeSynonymInstances
+    UndecidableInstances
+
+  if impl(ghc >=7.11)
+    other-extensions: PatternSynonyms
+
+-- Small, fast running tests.
+test-suite unit-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests
+  other-modules:
+    Test.Laws
+    Test.QuickCheck.Utils
+    UnitTests.Distribution.Compat.CreatePipe
+    UnitTests.Distribution.Compat.Graph
+    UnitTests.Distribution.Compat.Time
+    UnitTests.Distribution.Simple.Glob
+    UnitTests.Distribution.Simple.Program.Internal
+    UnitTests.Distribution.Simple.Utils
+    UnitTests.Distribution.SPDX
+    UnitTests.Distribution.System
+    UnitTests.Distribution.Types.GenericPackageDescription
+    UnitTests.Distribution.Utils.Generic
+    UnitTests.Distribution.Utils.NubList
+    UnitTests.Distribution.Utils.ShortText
+    UnitTests.Distribution.Version
+
+  main-is:          UnitTests.hs
+  build-depends:
+      array
+    , base
+    , bytestring
+    , Cabal
+    , containers
+    , directory
+    , filepath
+    , integer-logarithms  >=1.0.2   && <1.1
+    , pretty
+    , QuickCheck          >=2.11.3  && <2.12
+    , tagged
+    , tasty               >=1.1.0.3 && <1.2
+    , tasty-hunit
+    , tasty-quickcheck
+    , temporary
+    , text
+
+  ghc-options:      -Wall
+  default-language: Haskell2010
+
+test-suite parser-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests
+  main-is:          ParserTests.hs
+  build-depends:
+      base
+    , base-compat       >=0.10.4  && <0.11
+    , bytestring
+    , Cabal
+    , Diff              >=0.3.4   && <0.4
+    , directory
+    , filepath
+    , tasty             >=1.1.0.3 && <1.2
+    , tasty-golden      >=2.3.1.1 && <2.4
+    , tasty-hunit
+    , tasty-quickcheck
+
+  ghc-options:      -Wall
+  default-language: Haskell2010
+
+  if impl(ghc >=7.8)
+    build-depends: tree-diff >=0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+test-suite check-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests
+  main-is:          CheckTests.hs
+  build-depends:
+      base
+    , bytestring
+    , Cabal
+    , Diff          >=0.3.4   && <0.4
+    , directory
+    , filepath
+    , tasty         >=1.1.0.3 && <1.2
+    , tasty-golden  >=2.3.1.1 && <2.4
+
+  ghc-options:      -Wall
+  default-language: Haskell2010
+
+test-suite custom-setup-tests
+  type:             exitcode-stdio-1.0
+  hs-source-dirs:   tests/custom-setup
+  main-is:          CustomSetupTests.hs
+  other-modules:
+    CabalDoctestSetup
+    IdrisSetup
+
+  build-depends:
+      base
+    , Cabal
+    , directory
+    , filepath
+    , process
+
+  default-language: Haskell2010
+
+test-suite hackage-tests
+  type:               exitcode-stdio-1.0
+  main-is:            HackageTests.hs
+
+  -- TODO: need to get 01-index.tar on appveyor
+  if os(windows)
+    buildable: False
+
+  hs-source-dirs:     tests
+  build-depends:
+      base
+    , bytestring
+    , Cabal
+    , containers
+    , deepseq
+    , directory
+    , filepath
+
+  build-depends:
+      base-compat           >=0.10.4   && <0.11
+    , base-orphans          >=0.6      && <0.9
+    , optparse-applicative  >=0.13.2.0 && <0.15
+    , stm                   >=2.4.5.0  && <2.6
+    , tar                   >=0.5.0.3  && <0.6
+
+  if impl(ghc >=7.8)
+    build-depends: tree-diff >=0.0.1 && <0.1
+    other-modules:
+      Instances.TreeDiff
+      Instances.TreeDiff.Language
+      Instances.TreeDiff.SPDX
+      Instances.TreeDiff.Version
+
+  ghc-options:        -Wall -rtsopts -threaded
+  default-extensions: CPP
+  default-language:   Haskell2010
diff --git a/fixtures/cabal-fmt.cabal b/fixtures/cabal-fmt.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/cabal-fmt.cabal
@@ -0,0 +1,16 @@
+cabal-version: 2.4
+name: cabal-fmt
+version: 0
+
+-- An example formatter
+executable cabal-fmt
+    default-language: Haskell2010
+    hs-source-dirs: src 
+    main-is: CabalFmt.hs
+    -- build depends will be in
+    -- a nice tabular format
+    build-depends: base >=4.11 && <4.13, pretty >=1.1.3.6 && <1.2, bytestring, Cabal ^>=2.5, containers ^>=0.5.11.0 || ^>=0.6.0.1
+    -- extensions will be sorted
+    other-extensions:
+      DeriveFunctor FlexibleContexts ExistentialQuantification OverloadedStrings
+      RankNTypes
diff --git a/fixtures/cabal-fmt.format b/fixtures/cabal-fmt.format
new file mode 100644
--- /dev/null
+++ b/fixtures/cabal-fmt.format
@@ -0,0 +1,26 @@
+cabal-version: 2.4
+name:          cabal-fmt
+version:       0
+
+-- An example formatter
+executable cabal-fmt
+  default-language: Haskell2010
+  hs-source-dirs:   src
+  main-is:          CabalFmt.hs
+
+  -- build depends will be in
+  -- a nice tabular format
+  build-depends:
+    , base        >=4.11      && <4.13
+    , bytestring
+    , Cabal       ^>=2.5
+    , containers  ^>=0.5.11.0 || ^>=0.6.0.1
+    , pretty      >=1.1.3.6   && <1.2
+
+  -- extensions will be sorted
+  other-extensions:
+    DeriveFunctor
+    ExistentialQuantification
+    FlexibleContexts
+    OverloadedStrings
+    RankNTypes
diff --git a/fixtures/fragment-empty.cabal b/fixtures/fragment-empty.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-empty.cabal
@@ -0,0 +1,10 @@
+cabal-version:       2.4
+name:                fragment
+version:             1
+
+library
+  exposed-modules:     Example
+  -- cabal-gild: fragment empty.fragment
+  build-depends:       base >=4.3 && <4.13
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/fixtures/fragment-empty.format b/fixtures/fragment-empty.format
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-empty.format
@@ -0,0 +1,12 @@
+-- Fragment empty.fragment is empty.
+cabal-version: 2.4
+name:          fragment
+version:       1
+
+library
+  exposed-modules:  Example
+
+  -- cabal-gild: fragment empty.fragment
+  build-depends:    base >=4.3 && <4.13
+  hs-source-dirs:   src
+  default-language: Haskell2010
diff --git a/fixtures/fragment-missing.cabal b/fixtures/fragment-missing.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-missing.cabal
@@ -0,0 +1,10 @@
+cabal-version:       2.4
+name:                fragment
+version:             1
+
+library
+  exposed-modules:     Example
+  -- cabal-gild: fragment missing.fragment
+  build-depends:       base >=4.3 && <4.13
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/fixtures/fragment-missing.format b/fixtures/fragment-missing.format
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-missing.format
@@ -0,0 +1,12 @@
+-- Fragment missing.fragment failed to read: "doesn't exist"
+cabal-version: 2.4
+name:          fragment
+version:       1
+
+library
+  exposed-modules:  Example
+
+  -- cabal-gild: fragment missing.fragment
+  build-depends:    base >=4.3 && <4.13
+  hs-source-dirs:   src
+  default-language: Haskell2010
diff --git a/fixtures/fragment-multiple.cabal b/fixtures/fragment-multiple.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-multiple.cabal
@@ -0,0 +1,10 @@
+cabal-version:       2.4
+name:                fragment
+version:             1
+
+library
+  exposed-modules:     Example
+  -- cabal-gild: fragment multiple.fragment
+  build-depends:       base >=4.3 && <4.13
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/fixtures/fragment-multiple.format b/fixtures/fragment-multiple.format
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-multiple.format
@@ -0,0 +1,12 @@
+-- Fragment multiple.fragment contains multiple fields or sections, using only the first.
+cabal-version: 2.4
+name:          fragment
+version:       1
+
+library
+  exposed-modules:  Example
+
+  -- cabal-gild: fragment multiple.fragment
+  build-depends:    base
+  hs-source-dirs:   src
+  default-language: Haskell2010
diff --git a/fixtures/fragment-section.cabal b/fixtures/fragment-section.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-section.cabal
@@ -0,0 +1,12 @@
+cabal-version:       2.4
+name:                fragment
+version:             1
+
+-- cabal-gild: fragment common.fragment
+common deps
+
+library
+  import: deps
+  exposed-modules:     Example
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/fixtures/fragment-section.format b/fixtures/fragment-section.format
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-section.format
@@ -0,0 +1,18 @@
+cabal-version: 2.4
+name:          fragment
+version:       1
+
+-- cabal-gild: fragment common.fragment
+common deps
+  build-depends:
+    , base
+    , bytestring
+    , containers
+
+  ghc-options:   -Wall
+
+library
+  import:           deps
+  exposed-modules:  Example
+  hs-source-dirs:   src
+  default-language: Haskell2010
diff --git a/fixtures/fragment-wrong-field.cabal b/fixtures/fragment-wrong-field.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-wrong-field.cabal
@@ -0,0 +1,10 @@
+cabal-version:       2.4
+name:                fragment
+version:             1
+
+library
+  exposed-modules:     Example
+  -- cabal-gild: fragment tested-with.fragment
+  build-depends:       base >=4.3 && <4.13
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/fixtures/fragment-wrong-field.format b/fixtures/fragment-wrong-field.format
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-wrong-field.format
@@ -0,0 +1,12 @@
+-- Fragment tested-with.fragment contains field "tested-with", expecting field "build-depends".
+cabal-version: 2.4
+name:          fragment
+version:       1
+
+library
+  exposed-modules:  Example
+
+  -- cabal-gild: fragment tested-with.fragment
+  build-depends:    base >=4.3 && <4.13
+  hs-source-dirs:   src
+  default-language: Haskell2010
diff --git a/fixtures/fragment-wrong-type.cabal b/fixtures/fragment-wrong-type.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-wrong-type.cabal
@@ -0,0 +1,10 @@
+cabal-version:       2.4
+name:                fragment
+version:             1
+
+library
+  exposed-modules:     Example
+  -- cabal-gild: fragment common.fragment
+  build-depends:       base >=4.3 && <4.13
+  hs-source-dirs:      src
+  default-language:    Haskell2010
diff --git a/fixtures/fragment-wrong-type.format b/fixtures/fragment-wrong-type.format
new file mode 100644
--- /dev/null
+++ b/fixtures/fragment-wrong-type.format
@@ -0,0 +1,12 @@
+-- Fragment common.fragment contains a section "common deps", expecting field "build-depends".
+cabal-version: 2.4
+name:          fragment
+version:       1
+
+library
+  exposed-modules:  Example
+
+  -- cabal-gild: fragment common.fragment
+  build-depends:    base >=4.3 && <4.13
+  hs-source-dirs:   src
+  default-language: Haskell2010
diff --git a/fixtures/issue29.cabal b/fixtures/issue29.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/issue29.cabal
@@ -0,0 +1,22 @@
+cabal-version:      3.0
+name:               issue29
+version:            0
+description:
+  First Paragraph
+  
+
+
+
+
+  Second Paragraph
+
+library
+  default-language: Haskell2010
+  hs-source-dirs:   src
+  build-depends:
+      base        >=4.3   && <4.18
+
+  exposed-modules:
+    Data.Bifunctor.Assoc
+    Data.Bifunctor.Swap
+
diff --git a/fixtures/issue29.format b/fixtures/issue29.format
new file mode 100644
--- /dev/null
+++ b/fixtures/issue29.format
@@ -0,0 +1,15 @@
+cabal-version: 3.0
+name:          issue29
+version:       0
+description:
+  First Paragraph
+
+  Second Paragraph
+
+library
+  default-language: Haskell2010
+  hs-source-dirs:   src
+  build-depends:    base >=4.3 && <4.18
+  exposed-modules:
+    Data.Bifunctor.Assoc
+    Data.Bifunctor.Swap
diff --git a/fixtures/issue69.cabal b/fixtures/issue69.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/issue69.cabal
@@ -0,0 +1,18 @@
+cabal-version:      1.12
+name:               issue69
+version:            0
+
+library
+  default-language: Haskell2010
+  hs-source-dirs:   src
+  build-depends:
+      base        >=4.3   && <4.18
+    , bifunctors  >=5.5.5 && <5.6
+    , tagged      >=0.8.6 && <0.9
+    , inline-r    >1.0.0.0
+
+  exposed-modules:
+    Data.Bifunctor.Assoc
+    Data.Bifunctor.Swap
+
+  other-extensions: TypeFamilies
diff --git a/fixtures/issue69.format b/fixtures/issue69.format
new file mode 100644
--- /dev/null
+++ b/fixtures/issue69.format
@@ -0,0 +1,18 @@
+cabal-version: 1.12
+name:          issue69
+version:       0
+
+library
+  default-language: Haskell2010
+  hs-source-dirs:   src
+  build-depends:
+      base        >=4.3       && <4.18
+    , bifunctors  >=5.5.5     && <5.6
+    , inline-r    >=1.0.0.0.0
+    , tagged      >=0.8.6     && <0.9
+
+  exposed-modules:
+    Data.Bifunctor.Assoc
+    Data.Bifunctor.Swap
+
+  other-extensions: TypeFamilies
diff --git a/fixtures/simple-example.cabal b/fixtures/simple-example.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/simple-example.cabal
@@ -0,0 +1,74 @@
+name:                simple-example
+version:             1
+synopsis:            Simple example of cabal-doctest demonstrating a library
+                     with doctests
+description:         A package skeleton, to demostrate the use of cabal-doctest
+homepage:            https://github.com/phadej/cabal-doctest
+license:             BSD3
+license-file:        LICENSE
+author:              Oleg Grenrus <oleg.grenrus@iki.fi>
+maintainer:          Oleg Grenrus <oleg.grenrus@iki.fi>
+copyright:           (c) 2017 Oleg Grenrus
+category:            Example
+build-type:          Custom
+cabal-version:       1.12
+
+tested-with:
+  GHC==7.0.4,
+  GHC==7.2.2,
+  GHC==7.4.2,
+  GHC==7.6.3,
+  GHC==7.8.4,
+  GHC==7.10.3,
+  GHC==8.0.2,
+  GHC==8.2.2,
+  GHC==8.4.4,
+  GHC==8.6.3
+
+custom-setup
+  setup-depends:
+    base, Cabal, cabal-doctest >=1.0.6 && <1.1
+
+library
+  exposed-modules:     Example
+  default-extensions:  ScopedTypeVariables RankNTypes
+  build-depends:       base >=4.3 && <4.13
+  hs-source-dirs:      src
+  default-language:    Haskell2010
+
+  if impl(ghcjs)
+    cpp-options: -DFOOBAR
+
+  if impl(ghc)
+    -- cabal-gild: glob-files cbits/**/*.c
+    c-sources:
+
+  -- empty interval
+  if impl(hugs)
+    build-depends: unbuildable <0
+    build-depends: unbuildable <0, unbuildable2 <0
+
+  -- full interval
+  build-depends: text <1 || >=1
+  build-depends: containers <1 || >=1, pretty <1 || >=1
+
+  -- only upper bound
+  build-depends: foo <1
+  build-depends: foo <2
+  build-depends: abc <1, def <1, ghj <2
+
+  -- build-tool-depends are formatted like build-depends
+  build-tool-depends: happy:happy
+
+  build-tool-depends: happy:happy >=1, alex:alex >=1
+
+test-suite doctests
+  type:                exitcode-stdio-1.0
+  main-is:             doctests.hs
+
+  -- cabal-gild: fragment build-depends.fragment
+  build-depends:
+
+  ghc-options:         -Wall -threaded
+  hs-source-dirs:      tests
+  default-language:    Haskell2010
diff --git a/fixtures/simple-example.format b/fixtures/simple-example.format
new file mode 100644
--- /dev/null
+++ b/fixtures/simple-example.format
@@ -0,0 +1,96 @@
+name:          simple-example
+version:       1
+synopsis:
+  Simple example of cabal-doctest demonstrating a library
+  with doctests
+
+description:   A package skeleton, to demostrate the use of cabal-doctest
+homepage:      https://github.com/phadej/cabal-doctest
+license:       BSD3
+license-file:  LICENSE
+author:        Oleg Grenrus <oleg.grenrus@iki.fi>
+maintainer:    Oleg Grenrus <oleg.grenrus@iki.fi>
+copyright:     (c) 2017 Oleg Grenrus
+category:      Example
+build-type:    Custom
+cabal-version: 1.12
+tested-with:
+  GHC ==7.0.4
+   || ==7.2.2
+   || ==7.4.2
+   || ==7.6.3
+   || ==7.8.4
+   || ==7.10.3
+   || ==8.0.2
+   || ==8.2.2
+   || ==8.4.4
+   || ==8.6.3
+
+custom-setup
+  setup-depends:
+      base
+    , Cabal
+    , cabal-doctest  >=1.0.6 && <1.1
+
+library
+  exposed-modules:    Example
+  default-extensions:
+    RankNTypes
+    ScopedTypeVariables
+
+  build-depends:      base >=4.3 && <4.13
+  hs-source-dirs:     src
+  default-language:   Haskell2010
+
+  if impl(ghcjs)
+    cpp-options: -DFOOBAR
+
+  if impl(ghc)
+    -- cabal-gild: glob-files cbits/**/*.c
+    c-sources:
+      cbits/source1.c
+      cbits/source2.c
+      cbits/sub/source3.c
+
+  -- empty interval
+  if impl(hugs)
+    build-depends: unbuildable <0
+    build-depends:
+        unbuildable   <0
+      , unbuildable2  <0
+
+  -- full interval
+  build-depends:      text
+  build-depends:
+      containers
+    , pretty
+
+  -- only upper bound
+  build-depends:      foo <1
+  build-depends:      foo <2
+  build-depends:
+      abc  <1
+    , def  <1
+    , ghj  <2
+
+  -- build-tool-depends are formatted like build-depends
+  build-tool-depends: happy:happy
+  build-tool-depends:
+      alex:alex    >=1
+    , happy:happy  >=1
+
+test-suite doctests
+  type:             exitcode-stdio-1.0
+  main-is:          doctests.hs
+
+  -- cabal-gild: fragment build-depends.fragment
+  build-depends:
+      base
+    , doctest           >=0.15 && <0.17
+    , QuickCheck        >=2.12 && <2.13
+    , simple-example
+    , template-haskell
+
+  ghc-options:      -Wall -threaded
+  hs-source-dirs:   tests
+  default-language: Haskell2010
diff --git a/fixtures/tree-diff.cabal b/fixtures/tree-diff.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/tree-diff.cabal
@@ -0,0 +1,190 @@
+cabal-version:      2.2
+name:               tree-diff
+version:            0.2.2
+synopsis:           Diffing of (expression) trees.
+category:           Data, Testing
+description:
+  Common diff algorithm works on list structures:
+  .
+  @
+  diff :: Eq a => [a] -> [a] -> [Edit a]
+  @
+  .
+  This package works on trees.
+  .
+  @
+  treeDiff :: Eq a => Tree a -> Tree a -> Edit (EditTree a)
+  @
+  .
+  This package also provides a way to diff arbitrary ADTs,
+  using @Generics@-derivable helpers.
+  .
+  This package differs from <http://hackage.haskell.org/package/gdiff gdiff>,
+  in a two ways: @tree-diff@ doesn't have patch function,
+  and the "edit-script" is a tree itself, which is useful for pretty-printing.
+  .
+  @
+  >>> prettyEditExpr $ ediff (Foo 42 [True, False] "old") (Foo 42 [False, False, True] "new")
+  Foo
+  \  {fooBool = [-True, +False, False, +True],
+  \   fooInt = 42,
+  \   fooString = -"old" +"new"}
+  @
+
+homepage:           https://github.com/phadej/tree-diff
+bug-reports:        https://github.com/phadej/tree-diff/issues
+license:            GPL-2.0-or-later
+license-file:       LICENSE
+author:             Oleg Grenrus <oleg.grenrus@iki.fi>
+maintainer:         Oleg.Grenrus <oleg.grenrus@iki.fi>
+copyright:          (c) 2017-2021 Oleg Grenrus
+build-type:         Simple
+extra-source-files:
+  ChangeLog.md
+  README.md
+
+tested-with:
+    GHC ==7.4.2
+     || ==7.6.3
+     || ==7.8.4
+     || ==7.10.3
+     || ==8.0.2
+     || ==8.2.2
+     || ==8.4.4
+     || ==8.6.5
+     || ==8.8.4
+     || ==8.10.4
+     || ==9.0.2
+     || ==9.2.4
+     || ==9.4.1
+  , GHCJS ==8.4
+
+extra-source-files:
+  fixtures/exfoo.expr
+  fixtures/MyInt1.expr
+  fixtures/MyInt2.expr
+  fixtures/MyInt3.expr
+  fixtures/Positional.expr
+
+source-repository head
+  type:     git
+  location: https://github.com/phadej/tree-diff.git
+
+library
+  exposed-modules:
+    Data.TreeDiff
+    Data.TreeDiff.Class
+    Data.TreeDiff.Expr
+    Data.TreeDiff.Golden
+    Data.TreeDiff.List
+    Data.TreeDiff.OMap
+    Data.TreeDiff.Parser
+    Data.TreeDiff.Pretty
+    Data.TreeDiff.QuickCheck
+    Data.TreeDiff.Tree
+
+  -- GHC boot libraries
+  build-depends:
+    , base        >=4.5      && <4.18
+    , bytestring  ^>=0.9.2.1 || ^>=0.10.0.2 || ^>=0.11.0.0
+    , containers  ^>=0.4.2.1 || ^>=0.5.0.0 || ^>=0.6.0.1
+    , deepseq     ^>=1.3.0.0 || ^>=1.4.0.0
+    , parsec      ^>=3.1.13.0
+    , pretty      ^>=1.1.1.0
+    , text        ^>=1.2.3.0 || ^>=2.0
+    , time        ^>=1.4      || ^>=1.5.0.1  || ^>=1.6.0.1  || ^>=1.8.0.2 || >=1.9.3 && <1.13
+
+  build-depends:
+    , aeson                 ^>=1.4.6.0 || ^>=1.5.6.0 || ^>=2.0.0.0 || ^>=2.1.0.0
+    , ansi-terminal         >=0.10       && <0.12
+    , ansi-wl-pprint        ^>=0.6.8.2
+    , base-compat           ^>=0.10.5 || ^>=0.11.0 || ^>=0.12.0
+    , bytestring-builder    ^>=0.10.8.2.0
+    , hashable              ^>=1.2.7.0 || ^>=1.3.0.0 || ^>=1.4.0.1
+    , parsers               ^>=0.12.10
+    , primitive             ^>=0.7.1.0
+    , QuickCheck            ^>=2.14.2
+    , scientific            ^>=0.3.6.2
+    , semialign             ^>=1.2.0.1
+    , strict                ^>=0.4.0.1
+    , tagged                ^>=0.8.6
+    , these                 ^>=1.1.1.1
+    , unordered-containers  ^>=0.2.8.0
+    , uuid-types            ^>=1.0.3
+    , vector                ^>=0.12.0.0 || ^>=0.13.0.0
+
+  if impl(ghc <7.5)
+    build-depends: ghc-prim
+
+  if !impl(ghc >=8.0)
+    build-depends: semigroups >=0.19.1 && <0.21
+
+  if !impl(ghc >=7.8)
+    build-depends: generic-deriving >=1.13.1 && <1.15
+
+  if !impl(ghc >=7.10)
+    build-depends:
+      , nats          ^>=1.1.2
+      , transformers  ^>=0.3.0.0 || ^>=0.4.2.0 || ^>=0.5.2.0
+      , void          ^>=0.7.3
+
+  other-extensions:
+    CPP
+    ConstraintKinds
+    DefaultSignatures
+    FlexibleContexts
+    GADTs
+    RankNTypes
+    ScopedTypeVariables
+    TypeOperators
+
+  hs-source-dirs:   src
+  default-language: Haskell2010
+
+test-suite tree-diff-test
+  default-language: Haskell2010
+  type:             exitcode-stdio-1.0
+  main-is:          Tests.hs
+  hs-source-dirs:   tests src-diff
+  ghc-options:      -Wall -threaded
+  other-modules:    RefDiffBy
+
+  -- dependencies from library
+  build-depends:
+    , ansi-terminal
+    , ansi-wl-pprint
+    , base
+    , base-compat
+    , parsec
+    , primitive
+    , QuickCheck
+    , tagged
+    , tree-diff
+
+  if impl(ghc <7.5)
+    build-depends: ghc-prim
+
+  -- extra dependencies
+  build-depends:
+    , tasty             ^>=1.2 || ^>=1.3.1 || ^>=1.4.2
+    , tasty-golden      ^>=2.3.1.1
+    , tasty-quickcheck  ^>=0.10.1
+    , trifecta          >=2       && <2.2
+
+benchmark tree-diff-bench
+  default-language: Haskell2010
+  type:             exitcode-stdio-1.0
+  main-is:          tree-diff-bench.hs
+  hs-source-dirs:   bench
+  ghc-options:      -Wall -threaded
+
+  -- dependencies from library
+  build-depends:
+    , base
+    , deepseq
+    , tree-diff
+
+  -- extra dependencies
+  build-depends:
+    , criterion  ^>=1.6.0.0
+    , Diff       ^>=0.4.0
diff --git a/fixtures/tree-diff.format b/fixtures/tree-diff.format
new file mode 100644
--- /dev/null
+++ b/fixtures/tree-diff.format
@@ -0,0 +1,190 @@
+cabal-version:      2.2
+name:               tree-diff
+version:            0.2.2
+synopsis:           Diffing of (expression) trees.
+category:           Data, Testing
+description:
+  Common diff algorithm works on list structures:
+  .
+  @
+  diff :: Eq a => [a] -> [a] -> [Edit a]
+  @
+  .
+  This package works on trees.
+  .
+  @
+  treeDiff :: Eq a => Tree a -> Tree a -> Edit (EditTree a)
+  @
+  .
+  This package also provides a way to diff arbitrary ADTs,
+  using @Generics@-derivable helpers.
+  .
+  This package differs from <http://hackage.haskell.org/package/gdiff gdiff>,
+  in a two ways: @tree-diff@ doesn't have patch function,
+  and the "edit-script" is a tree itself, which is useful for pretty-printing.
+  .
+  @
+  >>> prettyEditExpr $ ediff (Foo 42 [True, False] "old") (Foo 42 [False, False, True] "new")
+  Foo
+  \  {fooBool = [-True, +False, False, +True],
+  \   fooInt = 42,
+  \   fooString = -"old" +"new"}
+  @
+
+homepage:           https://github.com/phadej/tree-diff
+bug-reports:        https://github.com/phadej/tree-diff/issues
+license:            GPL-2.0-or-later
+license-file:       LICENSE
+author:             Oleg Grenrus <oleg.grenrus@iki.fi>
+maintainer:         Oleg.Grenrus <oleg.grenrus@iki.fi>
+copyright:          (c) 2017-2021 Oleg Grenrus
+build-type:         Simple
+extra-source-files:
+  ChangeLog.md
+  README.md
+
+tested-with:
+    GHC ==7.4.2
+     || ==7.6.3
+     || ==7.8.4
+     || ==7.10.3
+     || ==8.0.2
+     || ==8.2.2
+     || ==8.4.4
+     || ==8.6.5
+     || ==8.8.4
+     || ==8.10.4
+     || ==9.0.2
+     || ==9.2.4
+     || ==9.4.1
+  , GHCJS ==8.4
+
+extra-source-files:
+  fixtures/exfoo.expr
+  fixtures/MyInt1.expr
+  fixtures/MyInt2.expr
+  fixtures/MyInt3.expr
+  fixtures/Positional.expr
+
+source-repository head
+  type:     git
+  location: https://github.com/phadej/tree-diff.git
+
+library
+  exposed-modules:
+    Data.TreeDiff
+    Data.TreeDiff.Class
+    Data.TreeDiff.Expr
+    Data.TreeDiff.Golden
+    Data.TreeDiff.List
+    Data.TreeDiff.OMap
+    Data.TreeDiff.Parser
+    Data.TreeDiff.Pretty
+    Data.TreeDiff.QuickCheck
+    Data.TreeDiff.Tree
+
+  -- GHC boot libraries
+  build-depends:
+    , base        >=4.5       && <4.18
+    , bytestring  ^>=0.9.2.1  || ^>=0.10.0.2 || ^>=0.11.0.0
+    , containers  ^>=0.4.2.1  || ^>=0.5.0.0  || ^>=0.6.0.1
+    , deepseq     ^>=1.3.0.0  || ^>=1.4.0.0
+    , parsec      ^>=3.1.13.0
+    , pretty      ^>=1.1.1.0
+    , text        ^>=1.2.3.0  || ^>=2.0
+    , time        ^>=1.4      || ^>=1.5.0.1  || ^>=1.6.0.1  || ^>=1.8.0.2 || ^>=1.9.3 || ^>=1.10 || ^>=1.11 || ^>=1.12
+
+  build-depends:
+    , aeson                 ^>=1.4.6.0    || ^>=1.5.6.0  || ^>=2.0.0.0 || ^>=2.1.0.0
+    , ansi-terminal         >=0.10        && <0.12
+    , ansi-wl-pprint        ^>=0.6.8.2
+    , base-compat           ^>=0.10.5     || ^>=0.11.0   || ^>=0.12.0
+    , bytestring-builder    ^>=0.10.8.2.0
+    , hashable              ^>=1.2.7.0    || ^>=1.3.0.0  || ^>=1.4.0.1
+    , parsers               ^>=0.12.10
+    , primitive             ^>=0.7.1.0
+    , QuickCheck            ^>=2.14.2
+    , scientific            ^>=0.3.6.2
+    , semialign             ^>=1.2.0.1
+    , strict                ^>=0.4.0.1
+    , tagged                ^>=0.8.6
+    , these                 ^>=1.1.1.1
+    , unordered-containers  ^>=0.2.8.0
+    , uuid-types            ^>=1.0.3
+    , vector                ^>=0.12.0.0   || ^>=0.13.0.0
+
+  if impl(ghc <7.5)
+    build-depends: ghc-prim
+
+  if !impl(ghc >=8.0)
+    build-depends: semigroups >=0.19.1 && <0.21
+
+  if !impl(ghc >=7.8)
+    build-depends: generic-deriving >=1.13.1 && <1.15
+
+  if !impl(ghc >=7.10)
+    build-depends:
+      , nats          ^>=1.1.2
+      , transformers  ^>=0.3.0.0 || ^>=0.4.2.0 || ^>=0.5.2.0
+      , void          ^>=0.7.3
+
+  other-extensions:
+    CPP
+    ConstraintKinds
+    DefaultSignatures
+    FlexibleContexts
+    GADTs
+    RankNTypes
+    ScopedTypeVariables
+    TypeOperators
+
+  hs-source-dirs:   src
+  default-language: Haskell2010
+
+test-suite tree-diff-test
+  default-language: Haskell2010
+  type:             exitcode-stdio-1.0
+  main-is:          Tests.hs
+  hs-source-dirs:   tests src-diff
+  ghc-options:      -Wall -threaded
+  other-modules:    RefDiffBy
+
+  -- dependencies from library
+  build-depends:
+    , ansi-terminal
+    , ansi-wl-pprint
+    , base
+    , base-compat
+    , parsec
+    , primitive
+    , QuickCheck
+    , tagged
+    , tree-diff
+
+  if impl(ghc <7.5)
+    build-depends: ghc-prim
+
+  -- extra dependencies
+  build-depends:
+    , tasty             ^>=1.2     || ^>=1.3.1 || ^>=1.4.2
+    , tasty-golden      ^>=2.3.1.1
+    , tasty-quickcheck  ^>=0.10.1
+    , trifecta          >=2        && <2.2
+
+benchmark tree-diff-bench
+  default-language: Haskell2010
+  type:             exitcode-stdio-1.0
+  main-is:          tree-diff-bench.hs
+  hs-source-dirs:   bench
+  ghc-options:      -Wall -threaded
+
+  -- dependencies from library
+  build-depends:
+    , base
+    , deepseq
+    , tree-diff
+
+  -- extra dependencies
+  build-depends:
+    , criterion  ^>=1.6.0.0
+    , Diff       ^>=0.4.0
diff --git a/fixtures/with-sublibs.cabal b/fixtures/with-sublibs.cabal
new file mode 100644
--- /dev/null
+++ b/fixtures/with-sublibs.cabal
@@ -0,0 +1,36 @@
+cabal-version: 3.0
+name:          with-sublibs
+version:       1
+
+library
+  hs-source-dirs:     src
+  default-language:   Haskell2010
+  build-depends:
+    test1,
+    test1:sub,
+    test2    >=1   &&  <3,
+    test2:sub    >=2 &&   <3
+
+  build-depends:
+    test1
+
+  build-depends:
+    test2 >=1
+
+  build-depends:
+    test2:sub
+
+  build-depends:
+    test2:{sub}
+
+  build-depends:
+    test2:{sub1, sub2}
+
+  build-depends:
+    test2:sub   >=1      && <3
+
+  build-depends:
+    test2:{sub}   >=2   && <3
+
+  build-depends:
+    test2:{sub1, sub2}   >=3 &&   <4
diff --git a/fixtures/with-sublibs.format b/fixtures/with-sublibs.format
new file mode 100644
--- /dev/null
+++ b/fixtures/with-sublibs.format
@@ -0,0 +1,20 @@
+Up to date
+cabal-version: 3.0
+name:          with-sublibs
+version:       1
+
+library
+  hs-source-dirs:   src
+  default-language: Haskell2010
+  build-depends:
+    , test1:{test1, sub}
+    , test2:{test2, sub}  >=2 && <3
+
+  build-depends:    test1
+  build-depends:    test2 >=1
+  build-depends:    test2:sub
+  build-depends:    test2:sub
+  build-depends:    test2:{sub1, sub2}
+  build-depends:    test2:sub >=1 && <3
+  build-depends:    test2:sub >=2 && <3
+  build-depends:    test2:{sub1, sub2} >=3 && <4
diff --git a/source/executable/Main.hs b/source/executable/Main.hs
new file mode 100644
--- /dev/null
+++ b/source/executable/Main.hs
@@ -0,0 +1,6 @@
+-- |
+-- License: BSD-3-Clause
+-- Copyright: Oleg Grenrus
+module Main (CabalGild.Main.main) where
+
+import qualified CabalGild.Main
diff --git a/source/library/CabalGild.hs b/source/library/CabalGild.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild.hs
@@ -0,0 +1,205 @@
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+--
+-- This is a demo application of how you can make Cabal-like
+-- file formatter.
+module CabalGild (cabalGild) where
+
+import CabalGild.Comments
+import CabalGild.Fields
+import CabalGild.Fields.BuildDepends
+import CabalGild.Fields.Extensions
+import CabalGild.Fields.Modules
+import CabalGild.Fields.SourceFiles
+import CabalGild.Fields.TestedWith
+import CabalGild.FreeText
+import CabalGild.Monad
+import CabalGild.Options
+import CabalGild.Parser
+import CabalGild.Pragma
+import CabalGild.Prelude
+import CabalGild.Refactoring
+import Control.Monad (join)
+import Control.Monad.Reader (asks, local)
+import qualified Data.ByteString as BS
+import Data.Functor (($>))
+import qualified Distribution.CabalSpecVersion as C
+import qualified Distribution.FieldGrammar.Parsec as C
+import qualified Distribution.Fields as C
+import qualified Distribution.Fields.ConfVar as C
+import qualified Distribution.Fields.Pretty as C
+import qualified Distribution.PackageDescription.FieldGrammar as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified Distribution.Types.Condition as C
+import qualified Distribution.Types.ConfVar as C
+import qualified Distribution.Types.GenericPackageDescription as C
+import qualified Distribution.Types.PackageDescription as C
+import qualified Distribution.Types.VersionRange as C
+import qualified Distribution.Utils.Generic as C
+import qualified Text.PrettyPrint as PP
+
+-------------------------------------------------------------------------------
+-- Main
+-------------------------------------------------------------------------------
+
+cabalGild :: (MonadCabalGild r m) => FilePath -> BS.ByteString -> m String
+cabalGild filepath contents = do
+  -- determine cabal-version
+  cabalFile <- asks (optCabalFile . view options)
+  csv <-
+    if cabalFile
+      then do
+        gpd <- parseGpd filepath contents
+        return $
+          C.specVersion $
+            C.packageDescription gpd
+      else return C.cabalSpecLatest
+
+  inputFields' <- parseFields contents
+  let (inputFieldsC, endComments) = attachComments contents inputFields'
+
+  -- parse pragmas
+  let parse :: (MonadCabalGild r f) => (a, Comments) -> f (a, Comments, [Pragma])
+      parse (pos, c) = case parsePragmas c of (ws, ps) -> traverse_ displayWarning ws $> (pos, c, ps)
+  inputFieldsP' <- traverse (traverse parse) inputFieldsC
+  endCommentsPragmas <- case parsePragmas endComments of
+    (ws, ps) -> traverse_ displayWarning ws $> ps
+
+  -- apply refactorings
+  let inputFieldsP :: [C.Field CommentsPragmas]
+      inputFieldsP = map (fmap (fmap (snd . partitionPragmas))) inputFieldsP'
+
+  inputFieldsR <- refactor inputFieldsP
+
+  -- options morphisms
+  let pragmas :: [GlobalPragma]
+      pragmas =
+        fst $
+          partitionPragmas $
+            foldMap (foldMap trdOf3) inputFieldsP' <> endCommentsPragmas
+
+      optsEndo :: OptionsMorphism
+      optsEndo = foldMap pragmaToOM pragmas
+
+  local (over options $ \o -> runOptionsMorphism optsEndo $ o {optSpecVersion = csv}) $ do
+    indentWith <- asks (optIndent . view options)
+    let inputFields = inputFieldsR
+
+    outputPrettyFields <-
+      genericFromParsecFields
+        (\n ann -> prettyFieldLines n (fstOf3 ann))
+        prettySectionArgs
+        inputFields
+
+    return $
+      C.showFields' (fromComments . sndOf3) (const id) indentWith outputPrettyFields
+        & if nullComments endComments
+          then id
+          else (++ unlines ("" : [C.fromUTF8BS c | c <- unComments endComments]))
+
+fromComments :: Comments -> C.CommentPosition
+fromComments (Comments []) = C.NoComment
+fromComments (Comments bss) = C.CommentBefore (map C.fromUTF8BS bss)
+
+genericFromParsecFields ::
+  (Applicative f) =>
+  -- | transform field contents
+  (C.FieldName -> ann -> [C.FieldLine ann] -> f PP.Doc) ->
+  -- | transform section arguments
+  (C.FieldName -> [C.SectionArg ann] -> f [PP.Doc]) ->
+  [C.Field ann] ->
+  f [C.PrettyField ann]
+genericFromParsecFields f g = goMany
+  where
+    goMany = traverse go
+
+    go (C.Field (C.Name ann name) fls) = C.PrettyField ann name <$> f name ann fls
+    go (C.Section (C.Name ann name) secargs fs) = C.PrettySection ann name <$> g name secargs <*> goMany fs
+
+-------------------------------------------------------------------------------
+-- Field prettyfying
+-------------------------------------------------------------------------------
+
+prettyFieldLines :: (MonadCabalGild r m) => C.FieldName -> C.Position -> [C.FieldLine CommentsPragmas] -> m PP.Doc
+prettyFieldLines fn pos fls =
+  fromMaybe (C.prettyFieldLines fn fls) <$> knownField fn pos fls
+
+knownField :: (MonadCabalGild r m) => C.FieldName -> C.Position -> [C.FieldLine CommentsPragmas] -> m (Maybe PP.Doc)
+knownField fn pos fls = do
+  opts <- asks (view options)
+  let v = optSpecVersion opts
+  let ft = fieldlinesToFreeText v pos (fmap (fmap fstOf3) fls)
+  let ft' = showFreeText v ft
+
+  return $ join $ fieldDescrLookup (fieldDescrs opts) fn (Just ft') $ \p pp ->
+    case C.runParsecParser' v p "<input>" (C.fieldLinesToStream fls) of
+      Right x -> Just (pp x)
+      Left _ -> Nothing
+
+fieldDescrs :: Options -> FieldDescrs () ()
+fieldDescrs opts =
+  buildDependsF opts
+    <> buildToolDependsF opts
+    <> setupDependsF opts
+    <> defaultExtensionsF
+    <> otherExtensionsF
+    <> exposedModulesF
+    <> otherModulesF
+    <> testedWithF opts
+    <> mconcat sourceFilesF
+    <> coerceFieldDescrs C.packageDescriptionFieldGrammar
+    <> coerceFieldDescrs C.buildInfoFieldGrammar
+
+-------------------------------------------------------------------------------
+-- Sections
+-------------------------------------------------------------------------------
+
+prettySectionArgs :: (MonadCabalGild r m) => C.FieldName -> [C.SectionArg ann] -> m [PP.Doc]
+prettySectionArgs x args =
+  prettySectionArgs' x args `catchError` \_ ->
+    return (C.prettySectionArgs x args)
+
+prettySectionArgs' :: (MonadCabalGild r m) => a -> [C.SectionArg ann] -> m [PP.Doc]
+prettySectionArgs' _ args = do
+  c <- runParseResult "<args>" "" $ C.parseConditionConfVar (map (C.zeroPos <$) args)
+  return [ppCondition c]
+
+-------------------------------------------------------------------------------
+-- PrettyPrint condition
+-------------------------------------------------------------------------------
+
+-- This is originally from Cabal
+
+ppCondition :: C.Condition C.ConfVar -> PP.Doc
+ppCondition (C.Var x) = ppConfVar x
+ppCondition (C.Lit b) = PP.text (show b)
+ppCondition (C.CNot c) = PP.char '!' PP.<> ppCondition c
+ppCondition (C.COr c1 c2) = PP.parens (PP.hsep [ppCondition c1, PP.text "||", ppCondition c2])
+ppCondition (C.CAnd c1 c2) = PP.parens (PP.hsep [ppCondition c1, PP.text "&&", ppCondition c2])
+
+ppConfVar :: C.ConfVar -> PP.Doc
+ppConfVar (C.OS os) = PP.text "os" PP.<> PP.parens (C.pretty os)
+ppConfVar (C.Arch arch) = PP.text "arch" PP.<> PP.parens (C.pretty arch)
+ppConfVar (C.PackageFlag name) = PP.text "flag" PP.<> PP.parens (C.pretty name)
+ppConfVar (C.Impl c v)
+  | v == C.anyVersion = PP.text "impl" PP.<> PP.parens (C.pretty c)
+  | otherwise = PP.text "impl" PP.<> PP.parens (C.pretty c PP.<+> C.pretty v)
+
+-------------------------------------------------------------------------------
+-- Pragma to OM
+-------------------------------------------------------------------------------
+
+partitionPragmas :: [Pragma] -> ([GlobalPragma], [FieldPragma])
+partitionPragmas = partitionEithers . map p
+  where
+    p (GlobalPragma x) = Left x
+    p (FieldPragma x) = Right x
+
+pragmaToOM :: GlobalPragma -> OptionsMorphism
+pragmaToOM (PragmaOptIndent n) = mkOptionsMorphism $ \opts -> opts {optIndent = n}
+pragmaToOM (PragmaOptTabular b) = mkOptionsMorphism $ \opts -> opts {optTabular = b}
diff --git a/source/library/CabalGild/Comments.hs b/source/library/CabalGild/Comments.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Comments.hs
@@ -0,0 +1,160 @@
+{-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Comments where
+
+import CabalGild.Prelude
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Char8 as BS8
+import qualified Data.Map.Strict as Map
+import qualified Distribution.Fields as C
+import qualified Distribution.Fields.Field as C
+import qualified Distribution.Parsec as C
+
+-------------------------------------------------------------------------------
+-- Comments wrapper
+-------------------------------------------------------------------------------
+
+newtype Comments = Comments [BS.ByteString]
+  deriving stock (Show)
+  deriving newtype (Semigroup, Monoid)
+
+unComments :: Comments -> [BS.ByteString]
+unComments (Comments cs) = cs
+
+nullComments :: Comments -> Bool
+nullComments (Comments cs) = null cs
+
+-------------------------------------------------------------------------------
+-- Attach comments
+-------------------------------------------------------------------------------
+
+-- | Returns a 'C.Field' forest with comments attached.
+--
+-- * Comments are attached to the field after it.
+-- * A glitch: comments "inside" the field are attached to the field after it.
+-- * End-of-file comments are returned separately.
+attachComments ::
+  -- | source with comments
+  BS.ByteString ->
+  -- | parsed source fields
+  [C.Field C.Position] ->
+  ([C.Field (C.Position, Comments)], Comments)
+attachComments input inputFields =
+  (overAnn attach attach' inputFields, endComments)
+  where
+    inputFieldsU :: [(FieldPath, C.Field C.Position)]
+    inputFieldsU = fieldUniverseN inputFields
+
+    comments :: [(Int, Comments)]
+    comments = extractComments input
+
+    comments' :: Map.Map FieldPath Comments
+    comments' =
+      Map.fromListWith
+        (flip (<>))
+        [ (path, cs)
+          | (l, cs) <- comments,
+            path <- toList (findPath C.fieldAnn l inputFieldsU)
+        ]
+
+    endComments :: Comments
+    endComments =
+      mconcat
+        [ cs
+          | (l, cs) <- comments,
+            isNothing (findPath C.fieldAnn l inputFieldsU)
+        ]
+
+    attach :: FieldPath -> C.Position -> (C.Position, Comments)
+    attach fp pos = (pos, fromMaybe mempty (Map.lookup fp comments'))
+
+    attach' :: C.Position -> (C.Position, Comments)
+    attach' pos = (pos, mempty)
+
+overAnn :: forall a b. (FieldPath -> a -> b) -> (a -> b) -> [C.Field a] -> [C.Field b]
+overAnn f h = go' id
+  where
+    go :: (FieldPath -> FieldPath) -> Int -> C.Field a -> C.Field b
+    go g i (C.Field (C.Name a name) fls) =
+      C.Field (C.Name b name) (h <$$> fls)
+      where
+        b = f (g (Nth i End)) a
+    go g i (C.Section (C.Name a name) args fls) =
+      C.Section (C.Name b name) (h <$$> args) (go' (g . Nth i) fls)
+      where
+        b = f (g (Nth i End)) a
+
+    go' :: (FieldPath -> FieldPath) -> [C.Field a] -> [C.Field b]
+    go' g = zipWith (go g) [0 ..]
+
+    (<$$>) :: (Functor f1, Functor f2) => (x -> y) -> f1 (f2 x) -> f1 (f2 y)
+    x <$$> y = (x <$>) <$> y
+
+-------------------------------------------------------------------------------
+-- Find comments in the input
+-------------------------------------------------------------------------------
+
+extractComments :: BS.ByteString -> [(Int, Comments)]
+extractComments = go . zip [1 ..] . map (BS.dropWhileEnd isCR . BS.dropWhile isSpace8) . BS8.lines
+  where
+    go :: [(Int, BS.ByteString)] -> [(Int, Comments)]
+    go [] = []
+    go ((n, bs) : rest)
+      | isComment bs = case span ((isComment .|| BS.null) . snd) rest of
+          (h, t) -> (n, Comments $ bs : map snd h) : go t
+      | otherwise = go rest
+
+    (.||) :: (t -> Bool) -> (t -> Bool) -> t -> Bool
+    (f .|| g) x = f x || g x
+
+    isSpace8 :: (Eq a, Num a) => a -> Bool
+    isSpace8 w = w == 9 || w == 32
+
+    isCR :: (Eq a, Num a) => a -> Bool
+    isCR = (==) 13
+
+    isComment :: BS.ByteString -> Bool
+    isComment = BS.isPrefixOf "--"
+
+-------------------------------------------------------------------------------
+-- FieldPath
+-------------------------------------------------------------------------------
+
+-- | Paths input paths. Essentially a list of offsets. Own type ofr safety.
+data FieldPath
+  = End
+  | Nth Int FieldPath -- nth field
+  deriving (Eq, Ord, Show)
+
+fieldUniverseN :: [C.Field ann] -> [(FieldPath, C.Field ann)]
+fieldUniverseN = concat . zipWith g [0 ..]
+  where
+    g :: Int -> C.Field ann -> [(FieldPath, C.Field ann)]
+    g n f' = [(Nth n p, f'') | (p, f'') <- fieldUniverse f']
+
+fieldUniverse :: C.Field ann -> [(FieldPath, C.Field ann)]
+fieldUniverse f@(C.Section _ _ fs) = (End, f) : concat (zipWith g [0 ..] fs)
+  where
+    g :: Int -> C.Field ann -> [(FieldPath, C.Field ann)]
+    g n f' = [(Nth n p, f'') | (p, f'') <- fieldUniverse f']
+fieldUniverse f@(C.Field _ _) = [(End, f)]
+
+-- note: fieldUniverse* should produce 'FieldPath's in increasing order
+-- that helps
+findPath :: (a -> C.Position) -> Int -> [(FieldPath, a)] -> Maybe FieldPath
+findPath _ _ [] = Nothing
+findPath f l [(p, x)]
+  | C.Position k _ <- f x =
+      if l < k then Just p else Nothing
+findPath f l ((_, x) : rest@((p, x') : _))
+  | C.Position k _ <- f x,
+    C.Position k' _ <- f x' =
+      if k < l && l < k'
+        then Just p
+        else findPath f l rest
diff --git a/source/library/CabalGild/Error.hs b/source/library/CabalGild/Error.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Error.hs
@@ -0,0 +1,128 @@
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Error (Error (..), renderError) where
+
+import Control.Exception (Exception)
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Char8 as BS8
+import Data.List.NonEmpty (NonEmpty)
+import qualified Distribution.Parsec as C
+import qualified Distribution.Types.Version as C
+import qualified Distribution.Utils.Generic as C (fromUTF8BS)
+import System.FilePath (normalise)
+import System.IO (hPutStr, hPutStrLn, stderr)
+import Text.Parsec.Error (ParseError)
+
+data Error
+  = SomeError String
+  | CabalParseError FilePath BS.ByteString (NonEmpty C.PError) (Maybe C.Version) [C.PWarning]
+  | PanicCannotParseInput ParseError
+  | WarningError String
+  deriving (Show)
+
+instance Exception Error
+
+renderError :: Error -> IO ()
+renderError (SomeError err) = hPutStrLn stderr $ "error: " ++ err
+renderError (PanicCannotParseInput err) = hPutStrLn stderr $ "panic! " ++ show err
+renderError (CabalParseError filepath contents errors _ warnings) =
+  hPutStr stderr $ renderParseError filepath contents errors warnings
+renderError (WarningError w) = hPutStrLn stderr $ "error (-Werror): " ++ w
+
+-------------------------------------------------------------------------------
+-- Rendering of Cabal parser error
+-------------------------------------------------------------------------------
+
+-- | Render parse error highlighting the part of the input file.
+renderParseError ::
+  FilePath ->
+  BS.ByteString ->
+  NonEmpty C.PError ->
+  [C.PWarning] ->
+  String
+renderParseError filepath contents errors warnings =
+  unlines $
+    [ "Errors encountered when parsing cabal file " <> filepath <> ":"
+    ]
+      ++ renderedErrors
+      ++ renderedWarnings
+  where
+    filepath' = normalise filepath
+
+    -- lines of the input file. 'lines' is taken, so they are called rows
+    -- contents, line number, whether it's empty line
+    rows :: [(String, Int, Bool)]
+    rows = zipWith f (BS8.lines contents) [1 ..]
+      where
+        f :: BS8.ByteString -> b -> (String, b, Bool)
+        f bs i = let s = C.fromUTF8BS bs in (s, i, isEmptyOrComment s)
+
+    rowsZipper = listToZipper rows
+
+    isEmptyOrComment :: String -> Bool
+    isEmptyOrComment s = case dropWhile (== ' ') s of
+      "" -> True -- empty
+      ('-' : '-' : _) -> True -- comment
+      _ -> False
+
+    renderedErrors = concatMap renderError' errors
+    renderedWarnings = concatMap renderWarning warnings
+
+    renderError' :: C.PError -> [String]
+    renderError' (C.PError pos@(C.Position row col) msg)
+      -- if position is 0:0, then it doesn't make sense to show input
+      -- looks like, Parsec errors have line-feed in them
+      | pos == C.zeroPos = msgs
+      | otherwise = msgs ++ formatInput row col
+      where
+        msgs = ["", filepath' ++ ":" ++ C.showPos pos ++ ": error:", trimLF msg, ""]
+
+    renderWarning :: C.PWarning -> [String]
+    renderWarning (C.PWarning _ pos@(C.Position row col) msg)
+      | pos == C.zeroPos = msgs
+      | otherwise = msgs ++ formatInput row col
+      where
+        msgs = ["", filepath' ++ ":" ++ C.showPos pos ++ ": warning:", trimLF msg, ""]
+
+    -- sometimes there are (especially trailing) newlines.
+    trimLF :: String -> String
+    trimLF = dropWhile (== '\n') . reverse . dropWhile (== '\n') . reverse
+
+    -- format line: prepend the given line number
+    formatInput :: Int -> Int -> [String]
+    formatInput row col = case advance (row - 1) rowsZipper of
+      Zipper xs ys -> before ++ after
+        where
+          before = case span (\(_, _, b) -> b) xs of
+            (_, []) -> []
+            (zs, z : _) -> map formatInputLine $ z : reverse zs
+
+          after = case ys of
+            [] -> []
+            (z : _zs) ->
+              [ formatInputLine z, -- error line
+                "      | " ++ replicate (col - 1) ' ' ++ "^" -- pointer: ^
+              ]
+    -- do we need rows after?
+    -- ++ map formatInputLine (take 1 zs)           -- one row after
+
+    formatInputLine :: (String, Int, Bool) -> String
+    formatInputLine (str, row, _) = leftPadShow row ++ " | " ++ str
+
+    -- hopefully we don't need to work with over 99999 lines .cabal files
+    -- at that point small glitches in error messages are hopefully fine.
+    leftPadShow :: Int -> String
+    leftPadShow n = let s = show n in replicate (5 - length s) ' ' ++ s
+
+data Zipper a = Zipper [a] [a]
+
+listToZipper :: [a] -> Zipper a
+listToZipper = Zipper []
+
+advance :: Int -> Zipper a -> Zipper a
+advance n z@(Zipper xs ys)
+  | n <= 0 = z
+  | otherwise = case ys of
+      [] -> z
+      (y : ys') -> advance (n - 1) $ Zipper (y : xs) ys'
diff --git a/source/library/CabalGild/Fields.hs b/source/library/CabalGild/Fields.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Fields.hs
@@ -0,0 +1,117 @@
+{-# LANGUAGE DeriveFunctor #-}
+{-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE UndecidableInstances #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Fields
+  ( FieldDescrs,
+    fieldDescrLookup,
+    coerceFieldDescrs,
+    singletonF,
+  )
+where
+
+import CabalGild.Prelude
+import qualified Data.Map.Strict as Map
+import qualified Distribution.FieldGrammar as C
+import qualified Distribution.Fields.Field as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified Text.PrettyPrint as PP
+
+-------------------------------------------------------------------------------
+-- FieldDescr variant
+-------------------------------------------------------------------------------
+
+-- strict pair
+data SP where
+  FreeText :: SP
+  SP ::
+    !(f -> PP.Doc) ->
+    !(forall m. (C.CabalParsing m) => m f) ->
+    SP
+
+-- | Lookup both pretty-printer and value parser.
+--
+-- As the value of the field is unknown, we have to work with it universally.
+fieldDescrLookup ::
+  (C.CabalParsing m) =>
+  FieldDescrs s a ->
+  C.FieldName ->
+  r -> -- field is freetext
+  (forall f. m f -> (f -> PP.Doc) -> r) ->
+  Maybe r
+fieldDescrLookup (F m) fn ft kont = kont' <$> Map.lookup fn m
+  where
+    kont' (SP a b) = kont b a
+    kont' FreeText = ft
+
+-- | A collection field parsers and pretty-printers.
+newtype FieldDescrs s a = F {runF :: Map.Map C.FieldName SP}
+  deriving (Functor)
+
+coerceFieldDescrs :: FieldDescrs s a -> FieldDescrs () ()
+coerceFieldDescrs (F a) = F a
+
+instance Semigroup (FieldDescrs s a) where
+  F a <> F b = F (a <> b)
+
+instance Monoid (FieldDescrs s a) where
+  mempty = F Map.empty
+  mappend = (<>)
+
+instance Applicative (FieldDescrs s) where
+  pure _ = F mempty
+  f <*> x = F (mappend (runF f) (runF x))
+
+singletonF ::
+  C.FieldName ->
+  (f -> PP.Doc) ->
+  (forall m. (C.CabalParsing m) => m f) ->
+  FieldDescrs s a
+singletonF fn f g = F $ Map.singleton fn (SP f g)
+
+instance C.FieldGrammar PrettyParsec FieldDescrs where
+  blurFieldGrammar _ (F m) = F m
+
+  booleanFieldDef fn _ _def = singletonF fn f C.parsec
+    where
+      f :: Bool -> PP.Doc
+      f s = PP.text (show s)
+
+  uniqueFieldAla fn _pack _ =
+    singletonF fn (C.pretty . pack' _pack) (unpack' _pack <$> C.parsec)
+
+  optionalFieldAla fn _pack _ =
+    singletonF fn (C.pretty . pack' _pack) (unpack' _pack <$> C.parsec)
+
+  optionalFieldDefAla fn _pack _ def =
+    singletonF fn f (unpack' _pack <$> C.parsec)
+    where
+      f s
+        | s == def = PP.empty
+        | otherwise = C.pretty (pack' _pack s)
+
+  monoidalFieldAla fn _pack _ =
+    singletonF fn (C.pretty . pack' _pack) (unpack' _pack <$> C.parsec)
+
+  freeTextField fn _ = F $ Map.singleton fn FreeText
+  freeTextFieldDef fn _ = F $ Map.singleton fn FreeText
+  freeTextFieldDefST fn _ = F $ Map.singleton fn FreeText
+
+  prefixedFields _fnPfx _l = F mempty
+  knownField _ = pure ()
+  deprecatedSince _ _ x = x
+  removedIn _ _ x = x
+  availableSince _ _ = id
+  hiddenField _ = F mempty
+
+class (C.Pretty a, C.Parsec a) => PrettyParsec a
+
+instance (C.Pretty a, C.Parsec a) => PrettyParsec a
diff --git a/source/library/CabalGild/Fields/BuildDepends.hs b/source/library/CabalGild/Fields/BuildDepends.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Fields/BuildDepends.hs
@@ -0,0 +1,159 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -Wno-deprecations #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Fields.BuildDepends
+  ( buildDependsF,
+    setupDependsF,
+    buildToolDependsF,
+  )
+where
+
+import CabalGild.Fields
+import CabalGild.Options
+import CabalGild.Prelude
+import Data.List (dropWhileEnd)
+import qualified Distribution.CabalSpecVersion as C
+import qualified Distribution.FieldGrammar as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified Distribution.Types.Dependency as C
+import qualified Distribution.Types.DependencyMap as C
+import qualified Distribution.Types.ExeDependency as C
+import qualified Distribution.Types.VersionRange as C
+import qualified Text.PrettyPrint as PP
+import VersionInterval (ConversionProblem (..), normaliseVersionRange)
+
+setupDependsF :: Options -> FieldDescrs () ()
+setupDependsF opts = singletonF "setup-depends" (pretty opts) parse
+
+buildDependsF :: Options -> FieldDescrs () ()
+buildDependsF opts = singletonF "build-depends" (pretty opts) parse
+
+buildToolDependsF :: Options -> FieldDescrs () ()
+buildToolDependsF opts = singletonF "build-tool-depends" (prettyExe opts) parseExe
+
+parse :: (C.CabalParsing m) => m [C.Dependency]
+parse = unpack' (C.alaList C.CommaVCat) <$> C.parsec
+
+parseExe :: (C.CabalParsing m) => m [C.ExeDependency]
+parseExe = unpack' (C.alaList C.CommaVCat) <$> C.parsec
+
+normaliseVersionRange' :: C.VersionRange -> C.VersionRange
+normaliseVersionRange' vr = either fromConversionProblem id (normaliseVersionRange vr)
+  where
+    fromConversionProblem :: ConversionProblem -> C.VersionRange
+    fromConversionProblem IntervalsEmpty = C.noVersion
+    fromConversionProblem OtherConversionProblem = vr
+
+pretty :: Options -> [C.Dependency] -> PP.Doc
+pretty opts deps = case deps of
+  [] -> PP.empty
+  [dep] -> PP.text (prettyDepNoVersion dep) PP.<+> prettyVR vr'
+    where
+      vr' = normaliseVersionRange' (C.depVerRange dep)
+
+      prettyVR vr
+        | vr == C.anyVersion = PP.empty
+        | vr == C.noVersion = PP.text "<0"
+        | otherwise = C.pretty vr
+  _ -> prettyMany opts deps'
+    where
+      deps' :: [(String, C.VersionRange)]
+      deps' =
+        sortOn (map toLower . fst) $
+          map (prettyDepNoVersion &&& C.depVerRange) $
+            C.fromDepMap . C.toDepMap $ -- this combines duplicate packages
+              deps
+  where
+    prettyDepNoVersion :: C.Dependency -> String
+    prettyDepNoVersion (C.Dependency pkg _ libs) =
+      C.prettyShow (C.Dependency pkg C.anyVersion libs)
+
+prettyExe :: Options -> [C.ExeDependency] -> PP.Doc
+prettyExe opts deps = case deps of
+  [] -> PP.empty
+  [dep] -> PP.text (exeDepExeName dep) PP.<+> prettyVR vr'
+    where
+      vr' = normaliseVersionRange' (exeDepVerRange dep)
+
+      prettyVR vr
+        | vr == C.anyVersion = PP.empty
+        | vr == C.noVersion = PP.text "<0"
+        | otherwise = C.pretty vr
+  _ -> prettyMany opts deps'
+    where
+      deps' :: [(String, C.VersionRange)]
+      deps' =
+        sortOn (map toLower . fst) $
+          map
+            (exeDepExeName &&& exeDepVerRange)
+            -- C.fromDepMap . C.toDepMap -- this combines duplicate packages
+            deps
+
+exeDepExeName :: C.ExeDependency -> String
+exeDepExeName (C.ExeDependency name exe _) =
+  C.prettyShow name ++ ":" ++ C.prettyShow exe
+
+exeDepVerRange :: C.ExeDependency -> C.VersionRange
+exeDepVerRange (C.ExeDependency _ _ vr) = vr
+
+prettyMany :: Options -> [(String, C.VersionRange)] -> PP.Doc
+prettyMany Options {optSpecVersion = v, optTabular = tab} deps' =
+  PP.vcat $
+    map PP.text $
+      tbl $
+        zipWith cols (True : repeat False) deps'
+  where
+    cols :: Bool -> (String, C.VersionRange) -> [String]
+    cols isFirst (name, vr)
+      | full vr' = [comma, name]
+      | otherwise = comma : name : "" : words (C.prettyShow vr')
+      where
+        vr' = normaliseVersionRange' vr
+
+        comma :: String
+        comma
+          | isFirst, v < C.CabalSpecV2_2 = " "
+          | otherwise = ","
+
+    full :: C.VersionRange -> Bool
+    full vr = vr == C.anyVersion
+
+    tbl :: [[String]] -> [String]
+    tbl = if tab then table else map (concatSpaces . unwords)
+
+-- returns rows.
+table :: [[String]] -> [String]
+table cells = map strip rows
+  where
+    cols :: Int
+    rowWidths :: [Int]
+    rows :: [String]
+
+    (cols, rowWidths, rows) = foldr go (0, repeat 0, []) cells
+
+    go :: [String] -> (Int, [Int], [String]) -> (Int, [Int], [String])
+    go xs (c, w, yss) =
+      ( max c (length xs),
+        zipWith max w (map length xs ++ repeat 0),
+        unwords (take cols (zipWith fill xs rowWidths))
+          : yss
+      )
+
+    fill :: String -> Int -> String
+    fill s n = s ++ replicate (n - length s) ' '
+
+strip :: String -> String
+strip = dropWhileEnd (' ' ==)
+
+concatSpaces :: String -> String
+concatSpaces [] = []
+concatSpaces (' ' : s) = ' ' : concatSpaces s
+concatSpaces (c0 : s0) = c0 : go s0
+  where
+    go (' ' : ' ' : s) = go (' ' : s)
+    go (c : s) = c : go s
+    go [] = []
diff --git a/source/library/CabalGild/Fields/Extensions.hs b/source/library/CabalGild/Fields/Extensions.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Fields/Extensions.hs
@@ -0,0 +1,30 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Fields.Extensions
+  ( otherExtensionsF,
+    defaultExtensionsF,
+  )
+where
+
+import CabalGild.Fields
+import CabalGild.Prelude
+import qualified Distribution.FieldGrammar as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified Language.Haskell.Extension as C
+import qualified Text.PrettyPrint as PP
+
+otherExtensionsF :: FieldDescrs () ()
+otherExtensionsF = singletonF "other-extensions" pretty parse
+
+defaultExtensionsF :: FieldDescrs () ()
+defaultExtensionsF = singletonF "default-extensions" pretty parse
+
+parse :: (C.CabalParsing m) => m [C.Extension]
+parse = unpack' (C.alaList' C.FSep C.MQuoted) <$> C.parsec
+
+pretty :: [C.Extension] -> PP.Doc
+pretty = PP.vcat . map C.pretty . sortOn C.prettyShow
diff --git a/source/library/CabalGild/Fields/Modules.hs b/source/library/CabalGild/Fields/Modules.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Fields/Modules.hs
@@ -0,0 +1,52 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Fields.Modules
+  ( otherModulesF,
+    exposedModulesF,
+  )
+where
+
+import CabalGild.Fields
+import CabalGild.Prelude
+import qualified Distribution.FieldGrammar as C
+import qualified Distribution.ModuleName as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified Text.PrettyPrint as PP
+
+exposedModulesF :: FieldDescrs () ()
+exposedModulesF = singletonF "exposed-modules" pretty parse
+
+otherModulesF :: FieldDescrs () ()
+otherModulesF = singletonF "other-modules" pretty parse
+
+parse :: (C.CabalParsing m) => m [C.ModuleName]
+parse = unpack' (C.alaList' C.VCat C.MQuoted) <$> C.parsec
+
+pretty :: [C.ModuleName] -> PP.Doc
+pretty =
+  PP.vcat
+    . map C.pretty
+    . nub
+    . sortBy (cmp `on` map strToLower . C.components)
+  where
+    cmp :: (Ord a) => [a] -> [a] -> Ordering
+    cmp a b = case dropCommonPrefix a b of
+      ([], []) -> EQ
+      ([], _ : _) -> LT
+      (_ : _, []) -> GT
+      (a', b') -> compare a' b'
+
+strToLower :: String -> String
+strToLower = map toLower
+
+dropCommonPrefix :: (Eq a) => [a] -> [a] -> ([a], [a])
+dropCommonPrefix [] [] = ([], [])
+dropCommonPrefix [] ys = ([], ys)
+dropCommonPrefix xs [] = (xs, [])
+dropCommonPrefix xs@(x : xs') ys@(y : ys')
+  | x == y = dropCommonPrefix xs' ys'
+  | otherwise = (xs, ys)
diff --git a/source/library/CabalGild/Fields/SourceFiles.hs b/source/library/CabalGild/Fields/SourceFiles.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Fields/SourceFiles.hs
@@ -0,0 +1,71 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Fields.SourceFiles
+  ( sourceFilesF,
+    fileFields,
+  )
+where
+
+-- Make sure we explicitly use Posix's splitDirectories
+-- when parsing glob syntax since only `/` is valid, and not '\\'
+
+import CabalGild.Fields
+import CabalGild.Prelude
+import qualified Distribution.FieldGrammar as C
+import qualified Distribution.Fields as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified System.FilePath.Posix as Posix (splitDirectories)
+import qualified Text.PrettyPrint as PP
+
+sourceFilesF :: [FieldDescrs () ()]
+sourceFilesF =
+  [ singletonF f pretty parse
+    | f <- fileFields
+  ]
+
+fileFields :: [C.FieldName]
+fileFields =
+  [ "extra-source-files",
+    "extra-doc-files",
+    "data-files",
+    "license-files",
+    "asm-sources",
+    "cmm-sources",
+    "c-sources",
+    "cxx-sources",
+    "js-sources",
+    "includes",
+    "install-includes"
+  ]
+
+parse :: (C.CabalParsing m) => m [FilePath]
+parse = unpack' (C.alaList' C.VCat C.FilePathNT) <$> C.parsec
+
+pretty :: [FilePath] -> PP.Doc
+pretty =
+  PP.vcat
+    . map C.showFilePath
+    . nub
+    . sortBy (cmp `on` map strToLower . Posix.splitDirectories)
+  where
+    cmp :: (Ord a) => [a] -> [a] -> Ordering
+    cmp a b = case dropCommonPrefix a b of
+      ([], []) -> EQ
+      ([], _ : _) -> LT
+      (_ : _, []) -> GT
+      (a', b') -> compare a' b'
+
+strToLower :: String -> String
+strToLower = map toLower
+
+dropCommonPrefix :: (Eq a) => [a] -> [a] -> ([a], [a])
+dropCommonPrefix [] [] = ([], [])
+dropCommonPrefix [] ys = ([], ys)
+dropCommonPrefix xs [] = (xs, [])
+dropCommonPrefix xs@(x : xs') ys@(y : ys')
+  | x == y = dropCommonPrefix xs' ys'
+  | otherwise = (xs, ys)
diff --git a/source/library/CabalGild/Fields/TestedWith.hs b/source/library/CabalGild/Fields/TestedWith.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Fields/TestedWith.hs
@@ -0,0 +1,71 @@
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Fields.TestedWith
+  ( testedWithF,
+  )
+where
+
+import CabalGild.Fields
+import CabalGild.Options
+import CabalGild.Prelude
+import qualified Data.Map.Strict as Map
+import qualified Data.Set as Set
+import qualified Distribution.CabalSpecVersion as C
+import qualified Distribution.Compiler as C
+import qualified Distribution.FieldGrammar as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Pretty as C
+import qualified Distribution.Version as C
+import qualified Text.PrettyPrint as PP
+
+testedWithF :: Options -> FieldDescrs () ()
+testedWithF Options {optSpecVersion = ver} = singletonF "tested-with" pretty parse
+  where
+    parse :: (C.CabalParsing m) => m [(C.CompilerFlavor, C.VersionRange)]
+    parse = unpack' (C.alaList' C.FSep C.TestedWith) <$> C.parsec
+
+    pretty :: [(C.CompilerFlavor, C.VersionRange)] -> PP.Doc
+    pretty tw0 =
+      leadingComma
+        ver
+        [ prettyC c PP.<+> prettyVr vr
+          | (c, vr) <- Map.toList tw1
+        ]
+      where
+        tw1 :: Map.Map C.CompilerFlavor C.VersionRange
+        tw1 = Map.fromListWith C.unionVersionRanges tw0
+
+        -- TODO: Cabal 3.0 formatting!
+        prettyVr vr = case isVersionSet vr of
+          Just vs -> PP.sep $ mapTail (\doc -> PP.nest (-3) $ PP.text "||" PP.<+> doc) [C.pretty (C.thisVersion v) | v <- Set.toList vs]
+          Nothing -> C.pretty vr
+
+        prettyC C.GHC = PP.text "GHC"
+        prettyC C.GHCJS = PP.text "GHCJS"
+        prettyC c = C.pretty c
+
+leadingComma :: C.CabalSpecVersion -> [PP.Doc] -> PP.Doc
+leadingComma _ [] = PP.empty
+leadingComma _ [x] = x
+leadingComma v xs = PP.vcat $ zipWith comma (True : repeat False) xs
+  where
+    comma :: Bool -> PP.Doc -> PP.Doc
+    comma isFirst doc
+      | isFirst, v < C.CabalSpecV3_0 = PP.char ' ' PP.<+> doc
+      | otherwise = PP.char ',' PP.<+> doc
+
+isVersionSet :: C.VersionRange -> Maybe (Set C.Version)
+isVersionSet vr = go Set.empty (C.asVersionIntervals vr)
+  where
+    go !acc [] = Just acc
+    go acc (C.VersionInterval (C.LowerBound v C.InclusiveBound) (C.UpperBound u C.InclusiveBound) : vis)
+      | v == u = go (Set.insert v acc) vis
+    go _ _ = Nothing
+
+mapTail :: (a -> a) -> [a] -> [a]
+mapTail _ [] = []
+mapTail f (x : xs) = x : map f xs
diff --git a/source/library/CabalGild/FreeText.hs b/source/library/CabalGild/FreeText.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/FreeText.hs
@@ -0,0 +1,85 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module CabalGild.FreeText
+  ( fieldlinesToFreeText,
+    showFreeText,
+  )
+where
+
+import CabalGild.Prelude
+import Data.List (foldl')
+import qualified Distribution.CabalSpecVersion as C
+import qualified Distribution.Fields.Field as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Parsec.Position as C
+import qualified Distribution.Pretty as C
+import qualified Distribution.Utils.String as C (trim)
+import qualified Text.PrettyPrint as PP
+
+showFreeText :: C.CabalSpecVersion -> String -> PP.Doc
+showFreeText v
+  | v >= C.CabalSpecV3_0 =
+      C.showFreeTextV3
+  | otherwise =
+      C.showFreeText
+
+-- This should perfectly be exported from Cabal-syntax
+fieldlinesToFreeText :: C.CabalSpecVersion -> C.Position -> [C.FieldLine C.Position] -> String
+fieldlinesToFreeText v
+  | v >= C.CabalSpecV3_0 =
+      fieldlinesToFreeText3
+  | otherwise =
+      const fieldlinesToFreeText2
+
+fieldlinesToFreeText2 :: [C.FieldLine C.Position] -> String
+fieldlinesToFreeText2 [C.FieldLine _ "."] = "."
+fieldlinesToFreeText2 fls = intercalate "\n" (map go fls)
+  where
+    go :: C.FieldLine ann -> String
+    go (C.FieldLine _ bs)
+      | s == "." = ""
+      | otherwise = s
+      where
+        s = C.trim (fromUTF8BS bs)
+
+fieldlinesToFreeText3 :: C.Position -> [C.FieldLine C.Position] -> String
+fieldlinesToFreeText3 _ [] = ""
+fieldlinesToFreeText3 _ [C.FieldLine _ bs] = fromUTF8BS bs
+fieldlinesToFreeText3 pos (C.FieldLine pos1 bs1 : fls2@(C.FieldLine pos2 _ : _))
+  -- if first line is on the same line with field name:
+  -- the indentation level is either
+  -- 1. the indentation of left most line in rest fields
+  -- 2. the indentation of the first line
+  -- whichever is leftmost
+  | C.positionRow pos == C.positionRow pos1 =
+      concat $
+        fromUTF8BS bs1
+          : mealy (mk mcol1) pos1 fls2
+  -- otherwise, also indent the first line
+  | otherwise =
+      concat $
+        replicate (C.positionCol pos1 - mcol2) ' '
+          : fromUTF8BS bs1
+          : mealy (mk mcol2) pos1 fls2
+  where
+    mcol1 = foldl' (\a b -> min a $ C.positionCol $ C.fieldLineAnn b) (min (C.positionCol pos1) (C.positionCol pos2)) fls2
+    mcol2 = foldl' (\a b -> min a $ C.positionCol $ C.fieldLineAnn b) (C.positionCol pos1) fls2
+
+    mk :: Int -> C.Position -> C.FieldLine C.Position -> (C.Position, String)
+    mk col p (C.FieldLine q bs) =
+      ( q,
+        -- in Cabal-syntax there is no upper limit, i.e. no min
+        -- we squash multiple empty lines to one
+        replicate (min 2 newlines) '\n'
+          ++ replicate indent ' '
+          ++ fromUTF8BS bs
+      )
+      where
+        newlines = C.positionRow q - C.positionRow p
+        indent = C.positionCol q - col
+
+mealy :: (s -> a -> (s, b)) -> s -> [a] -> [b]
+mealy f = go
+  where
+    go _ [] = []
+    go s (x : xs) = let ~(s', y) = f s x in y : go s' xs
diff --git a/source/library/CabalGild/Glob.hs b/source/library/CabalGild/Glob.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Glob.hs
@@ -0,0 +1,69 @@
+module CabalGild.Glob where
+
+import CabalGild.Prelude
+import Data.List (isInfixOf)
+import Data.List.NonEmpty (NonEmpty (..))
+import qualified System.FilePath as Native (splitDirectories)
+import qualified System.FilePath.Posix as Posix (splitDirectories)
+
+data Glob = Glob FilePath [GlobPiece]
+  deriving (Show)
+
+data GlobPiece
+  = GlobStarStar
+  | GlobPiece (NonEmpty GlobChar)
+  deriving (Show)
+
+data GlobChar
+  = GlobStar
+  | GlobChar Char
+  deriving (Show)
+
+-- | Match glob
+--
+-- >>> let Right g = parseGlob "cbits/**/*.c"
+--
+-- >>> map (match g) ["foo", "cbits/header.h", "cbits/source.c", "cbits/dir/source.c"]
+-- [False,False,True,True]
+match :: Glob -> FilePath -> Bool
+match (Glob g1 gs0) fp = go0 (Native.splitDirectories fp)
+  where
+    go0 [] = False
+    go0 (p : ps) = p == g1 && go ps gs0
+
+    go :: [FilePath] -> [GlobPiece] -> Bool
+    go [] [] = True
+    go [] (_ : _) = False
+    go (_ : _) [] = False
+    go (s : ss) (GlobStarStar : gs) = go (s : ss) gs || go ss (GlobStarStar : gs)
+    go (s : ss) (GlobPiece cs : gs) = matches s (toList cs) && go ss gs
+
+    matches :: FilePath -> [GlobChar] -> Bool
+    matches [] [] = True
+    matches (_ : _) [] = False
+    matches [] (_ : _) = False
+    matches (x : xs) (GlobStar : cs) = matches (x : xs) cs || matches xs (GlobStar : cs)
+    matches (x : xs) (GlobChar c : cs) = x == c && matches xs cs
+
+parseGlob :: String -> Either String Glob
+parseGlob input = case Posix.splitDirectories input of
+  [] -> Left "empty path"
+  (x : xs) -> do
+    p <- parseFirstPiece x
+    ps <- traverse parsePiece xs
+    return (Glob p ps)
+  where
+    parseFirstPiece :: String -> Either String FilePath
+    parseFirstPiece "" = Left "empty path segment"
+    parseFirstPiece s | "*" `isInfixOf` s = Left "wild card in first path segment"
+    parseFirstPiece s = Right s
+
+    parsePiece :: String -> Either String GlobPiece
+    parsePiece "" = Left "empty path segment"
+    parsePiece "**" = Right GlobStarStar
+    parsePiece s | "**" `isInfixOf` s = Left $ "** inside path segment: " ++ s
+    parsePiece (c : cs) = Right (GlobPiece (parseChar c :| map parseChar cs))
+
+    parseChar :: Char -> GlobChar
+    parseChar '*' = GlobStar
+    parseChar c = GlobChar c
diff --git a/source/library/CabalGild/Main.hs b/source/library/CabalGild/Main.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Main.hs
@@ -0,0 +1,140 @@
+-- |
+-- License: BSD-3-Clause
+-- Copyright: Oleg Grenrus
+module CabalGild.Main (main) where
+
+import CabalGild (cabalGild)
+import CabalGild.Error (renderError)
+import CabalGild.Monad (runCabalGildIO)
+import CabalGild.Options
+import CabalGild.Prelude
+import Control.Applicative (many, (<**>))
+import qualified Data.ByteString as BS
+import Data.Traversable (for)
+import Data.Version (showVersion)
+import qualified Options.Applicative as O
+import Paths_cabal_gild (version)
+import System.Exit (exitFailure)
+import System.FilePath (takeDirectory)
+import System.IO (hPutStrLn, stderr)
+
+main :: IO ()
+main = do
+  (opts', filepaths) <- O.execParser optsP'
+  let opts = runOptionsMorphism opts' defaultOptions
+
+  notFormatted <-
+    catMaybes <$> case filepaths of
+      [] -> fmap pure $ BS.getContents >>= main' opts Nothing
+      (_ : _) -> for filepaths $ \filepath -> do
+        contents <- BS.readFile filepath
+        main' opts (Just filepath) contents
+
+  when ((optMode opts == ModeCheck) && not (null notFormatted)) $ do
+    for_ notFormatted $ \filepath ->
+      hPutStrLn stderr $ "error: Input " <> filepath <> " is not formatted."
+    exitFailure
+  where
+    optsP' =
+      O.info (optsP <**> O.helper <**> versionP) $
+        mconcat
+          [ O.fullDesc,
+            O.progDesc "Reformat .cabal files",
+            O.header "cabal-gild - .cabal file reformatter"
+          ]
+
+    versionP :: O.Parser (a -> a)
+    versionP =
+      O.infoOption (showVersion version) $
+        O.long "version" <> O.help "Show version"
+
+main' :: Options -> Maybe FilePath -> BS.ByteString -> IO (Maybe FilePath)
+main' opts mfilepath input = do
+  -- name of the input
+  let filepath = fromMaybe "<stdin>" mfilepath
+
+  -- process
+  res <- runCabalGildIO (takeDirectory <$> mfilepath) opts (cabalGild filepath input)
+
+  case res of
+    Right output -> do
+      let outputBS = toUTF8BS output
+          formatted = outputBS == input
+
+      case optMode opts of
+        ModeStdout -> BS.putStr outputBS
+        ModeInplace -> case mfilepath of
+          Nothing -> BS.putStr outputBS
+          Just _ -> unless formatted $ BS.writeFile filepath outputBS
+        _ -> return ()
+
+      return $ if formatted then Nothing else Just filepath
+    Left err -> do
+      renderError err
+      exitFailure
+
+-------------------------------------------------------------------------------
+-- Options parser
+-------------------------------------------------------------------------------
+
+optsP :: O.Parser (OptionsMorphism, [FilePath])
+optsP =
+  (,)
+    <$> optsP'
+    <*> many (O.strArgument (O.metavar "FILE..." <> O.help "input files"))
+  where
+    optsP' =
+      fmap mconcat $
+        many $
+          asum
+            [ werrorP,
+              noWerrorP,
+              indentP,
+              tabularP,
+              noTabularP,
+              cabalFileP,
+              noCabalFileP,
+              stdoutP,
+              inplaceP,
+              checkP
+            ]
+
+    werrorP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optError = True}) $
+        O.long "Werror" <> O.help "Treat warnings as errors"
+
+    noWerrorP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optError = False}) $
+        O.long "Wno-error"
+
+    indentP =
+      O.option (fmap (\n -> mkOptionsMorphism $ \opts -> opts {optIndent = n}) O.auto) $
+        O.long "indent" <> O.help "Indentation" <> O.metavar "N"
+
+    tabularP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optTabular = True}) $
+        O.long "tabular" <> O.help "Tabular formatting"
+
+    noTabularP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optTabular = False}) $
+        O.long "no-tabular"
+
+    cabalFileP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optCabalFile = True}) $
+        O.long "cabal-file"
+
+    noCabalFileP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optCabalFile = False}) $
+        O.short 'n' <> O.long "no-cabal-file" <> O.help "Don't parse as .cabal file"
+
+    stdoutP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optMode = ModeStdout}) $
+        O.long "stdout" <> O.help "Write output to stdout (default)"
+
+    inplaceP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optMode = ModeInplace}) $
+        O.short 'i' <> O.long "inplace" <> O.help "Process files in-place"
+
+    checkP =
+      O.flag' (mkOptionsMorphism $ \opts -> opts {optMode = ModeCheck}) $
+        O.short 'c' <> O.long "check" <> O.help "Fail with non-zero exit code if input is not formatted"
diff --git a/source/library/CabalGild/Monad.hs b/source/library/CabalGild/Monad.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Monad.hs
@@ -0,0 +1,226 @@
+{-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Monad
+  ( -- * Monad class
+    MonadCabalGild (..),
+    getFiles,
+    Contents (..),
+
+    -- * Pure implementation
+    CabalGild,
+    runCabalGild,
+
+    -- * IO implementation
+    CabalGildIO,
+    runCabalGildIO,
+  )
+where
+
+import CabalGild.Error
+import CabalGild.Options
+import Control.Exception
+  ( IOException,
+    catch,
+    displayException,
+    throwIO,
+    try,
+  )
+import Control.Monad (when)
+import Control.Monad.Except (MonadError (..))
+import Control.Monad.IO.Class (MonadIO (..))
+import Control.Monad.Reader (MonadReader (..), ReaderT (..), asks, runReaderT)
+import Control.Monad.Writer (WriterT, runWriterT, tell)
+import Data.Bifunctor (first)
+import qualified Data.ByteString as BS
+import Data.List (isPrefixOf, stripPrefix)
+import qualified Data.Map as Map
+import Data.Maybe (mapMaybe)
+import qualified System.Directory as D
+import System.Exit (exitFailure)
+import System.FilePath (pathSeparator, (</>))
+import System.IO (hPutStrLn, stderr)
+
+-------------------------------------------------------------------------------
+-- Class
+-------------------------------------------------------------------------------
+
+-- | @cabal-gild@ interface.
+--
+-- * reader of 'Options'
+-- * errors of 'Error'
+-- * can list directories
+class (HasOptions r, MonadReader r m, MonadError Error m) => MonadCabalGild r m | m -> r where
+  listDirectory :: FilePath -> m [FilePath]
+  doesDirectoryExist :: FilePath -> m Bool
+
+  readFileBS :: FilePath -> m Contents
+
+  displayWarning :: String -> m ()
+
+data Contents
+  = Contents BS.ByteString
+  | NoIO
+  | IOError String
+
+-------------------------------------------------------------------------------
+-- Pure
+-------------------------------------------------------------------------------
+
+-- | Pure 'MonadCabalGild'.
+--
+-- 'listDirectory' always return empty list.
+newtype CabalGild a = CabalGild {unCabalGild :: ReaderT (Options, Map.Map FilePath BS.ByteString) (WriterT [String] (Either Error)) a}
+  deriving newtype (Functor, Applicative, Monad, MonadError Error)
+
+instance MonadReader Options CabalGild where
+  ask = CabalGild $ asks fst
+
+  local f (CabalGild m) = CabalGild $ local (first f) m
+
+instance MonadCabalGild Options CabalGild where
+  listDirectory dir = CabalGild $ do
+    files <- asks snd
+    return $ mapMaybe f (Map.keys files)
+    where
+      f :: FilePath -> Maybe FilePath
+      f fp = do
+        rest <- stripPrefix (dir ++ [pathSeparator]) fp
+        return $ takeWhile (/= pathSeparator) rest
+
+  doesDirectoryExist dir = CabalGild $ do
+    files <- asks snd
+    return (any (isPrefixOf (dir ++ [pathSeparator])) (Map.keys files))
+
+  readFileBS p = CabalGild $ do
+    files <- asks snd
+    return (maybe (IOError "doesn't exist") Contents $ Map.lookup p files)
+
+  displayWarning w = do
+    werror <- asks optError
+    if werror
+      then throwError $ WarningError w
+      else CabalGild $ tell [w]
+
+runCabalGild ::
+  Map.Map FilePath BS.ByteString ->
+  Options ->
+  CabalGild a ->
+  Either Error (a, [String])
+runCabalGild files opts m = runWriterT (runReaderT (unCabalGild m) (opts, files))
+
+-------------------------------------------------------------------------------
+-- IO
+-------------------------------------------------------------------------------
+
+-- | Options with root for directory traversals
+data Options' = Options'
+  { optRootDir :: Maybe FilePath,
+    optOpt :: Options
+  }
+
+instance HasOptions Options' where
+  options f (Options' mfp o) = Options' mfp <$> f o
+
+newtype CabalGildIO a = CabalGildIO {unCabalGildIO :: ReaderT Options' IO a}
+  deriving newtype (Functor, Applicative, Monad, MonadIO, MonadReader Options')
+
+instance MonadError Error CabalGildIO where
+  throwError = liftIO . throwIO
+  catchError m h = CabalGildIO $ ReaderT $ \r ->
+    catch (unCabalGildIO' r m) (unCabalGildIO' r . h)
+    where
+      unCabalGildIO' :: Options' -> CabalGildIO a -> IO a
+      unCabalGildIO' r m' = runReaderT (unCabalGildIO m') r
+
+instance MonadCabalGild Options' CabalGildIO where
+  listDirectory p = do
+    rd <- asks optRootDir
+    case rd of
+      Nothing -> return []
+      Just d -> liftIO (D.listDirectory (d </> p))
+  doesDirectoryExist p = do
+    rd <- asks optRootDir
+    case rd of
+      Nothing -> return False
+      Just d -> liftIO (D.doesDirectoryExist (d </> p))
+  readFileBS p = do
+    rd <- asks optRootDir
+    case rd of
+      Nothing -> return NoIO
+      Just d -> liftIO $ catchIOError $ BS.readFile (d </> p)
+  displayWarning w = do
+    werror <- asks (optError . optOpt)
+    liftIO $ do
+      hPutStrLn stderr $ (if werror then "ERROR: " else "WARNING: ") ++ w
+      when werror exitFailure
+
+catchIOError :: IO BS.ByteString -> IO Contents
+catchIOError m = catch (fmap Contents m) handler
+  where
+    handler :: IOException -> IO Contents
+    handler exc = return (IOError (displayException exc))
+
+runCabalGildIO :: Maybe FilePath -> Options -> CabalGildIO a -> IO (Either Error a)
+runCabalGildIO mfp opts m = try $ runReaderT (unCabalGildIO m) (Options' mfp opts)
+
+-------------------------------------------------------------------------------
+-- Files
+-------------------------------------------------------------------------------
+
+getFiles :: (MonadCabalGild r m) => FilePath -> m [FilePath]
+getFiles = getDirectoryContentsRecursive' check
+  where
+    check "dist-newstyle" = False
+    check ('.' : _) = False
+    check _ = True
+
+-- | List all the files in a directory and all subdirectories.
+--
+-- The order places files in sub-directories after all the files in their
+-- parent directories. The list is generated lazily so is not well defined if
+-- the source directory structure changes before the list is used.
+--
+-- /Note:/ From @Cabal@'s "Distribution.Simple.Utils"
+getDirectoryContentsRecursive' ::
+  forall m r.
+  (MonadCabalGild r m) =>
+  -- | Check, whether to recurse
+  (FilePath -> Bool) ->
+  -- | top dir
+  FilePath ->
+  m [FilePath]
+getDirectoryContentsRecursive' ignore' topdir = recurseDirectories [""]
+  where
+    recurseDirectories :: [FilePath] -> m [FilePath]
+    recurseDirectories [] = return []
+    recurseDirectories (dir : dirs) = do
+      (files, dirs') <- collect [] [] =<< listDirectory (topdir </> dir)
+      files' <- recurseDirectories (dirs' ++ dirs)
+      return (files ++ files')
+      where
+        collect :: [FilePath] -> [FilePath] -> [[Char]] -> m ([FilePath], [FilePath])
+        collect files dirs' [] =
+          return
+            ( reverse files,
+              reverse dirs'
+            )
+        collect files dirs' (entry : entries)
+          | ignore entry =
+              collect files dirs' entries
+        collect files dirs' (entry : entries) = do
+          let dirEntry = dir </> entry
+          isDirectory <- doesDirectoryExist (topdir </> dirEntry)
+          if isDirectory
+            then collect files (dirEntry : dirs') entries
+            else collect (dirEntry : files) dirs' entries
+
+        ignore ['.'] = True
+        ignore ['.', '.'] = True
+        ignore x = not (ignore' x)
diff --git a/source/library/CabalGild/Options.hs b/source/library/CabalGild/Options.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Options.hs
@@ -0,0 +1,64 @@
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Options
+  ( Mode (..),
+    Options (..),
+    defaultOptions,
+    OptionsMorphism,
+    mkOptionsMorphism,
+    runOptionsMorphism,
+    HasOptions (..),
+  )
+where
+
+import qualified Distribution.CabalSpecVersion as C
+import Distribution.Compat.Lens (LensLike')
+
+data Mode
+  = ModeStdout
+  | ModeInplace
+  | ModeCheck
+  deriving (Eq, Show)
+
+data Options = Options
+  { optError :: !Bool,
+    optIndent :: !Int,
+    optTabular :: !Bool,
+    optCabalFile :: !Bool,
+    optSpecVersion :: !C.CabalSpecVersion,
+    optMode :: !Mode
+  }
+  deriving (Show)
+
+defaultOptions :: Options
+defaultOptions =
+  Options
+    { optError = False,
+      optIndent = 2,
+      optTabular = True,
+      optCabalFile = True,
+      optSpecVersion = C.cabalSpecLatest,
+      optMode = ModeStdout
+    }
+
+newtype OptionsMorphism = OM (Options -> Options)
+
+runOptionsMorphism :: OptionsMorphism -> Options -> Options
+runOptionsMorphism (OM f) = f
+
+mkOptionsMorphism :: (Options -> Options) -> OptionsMorphism
+mkOptionsMorphism = OM
+
+instance Semigroup OptionsMorphism where
+  OM f <> OM g = OM (g . f)
+
+instance Monoid OptionsMorphism where
+  mempty = OM id
+  mappend = (<>)
+
+class HasOptions e where
+  options :: (Functor f) => LensLike' f e Options
+
+instance HasOptions Options where
+  options = id
diff --git a/source/library/CabalGild/Parser.hs b/source/library/CabalGild/Parser.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Parser.hs
@@ -0,0 +1,28 @@
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Parser where
+
+import CabalGild.Error
+import CabalGild.Monad
+import CabalGild.Prelude
+import qualified Data.ByteString as BS
+import qualified Distribution.Fields as C
+import qualified Distribution.PackageDescription.Parsec as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Types.GenericPackageDescription as C
+
+runParseResult :: (MonadCabalGild r m) => FilePath -> BS.ByteString -> C.ParseResult a -> m a
+runParseResult filepath contents pr = case result of
+  Right gpd -> return gpd
+  Left (mspecVersion, errors) -> throwError $ CabalParseError filepath contents errors mspecVersion warnings
+  where
+    (warnings, result) = C.runParseResult pr
+
+parseGpd :: (MonadCabalGild r m) => FilePath -> BS.ByteString -> m C.GenericPackageDescription
+parseGpd filepath contents = runParseResult filepath contents $ C.parseGenericPackageDescription contents
+
+parseFields :: (MonadCabalGild r m) => BS.ByteString -> m [C.Field C.Position]
+parseFields contents = case C.readFields contents of
+  Left err -> throwError $ PanicCannotParseInput err
+  Right x -> return x
diff --git a/source/library/CabalGild/Pragma.hs b/source/library/CabalGild/Pragma.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Pragma.hs
@@ -0,0 +1,98 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module CabalGild.Pragma where
+
+import CabalGild.Comments
+import CabalGild.Glob
+import CabalGild.Prelude
+import qualified Data.ByteString as BS
+import qualified Distribution.Compat.CharParsing as C
+import qualified Distribution.ModuleName as C
+import qualified Distribution.Parsec as C
+import qualified Distribution.Parsec.FieldLineStream as C
+
+-------------------------------------------------------------------------------
+-- Types
+-------------------------------------------------------------------------------
+
+data Pragma
+  = FieldPragma FieldPragma
+  | GlobalPragma GlobalPragma
+  deriving (Show)
+
+-- | Pragmas applied per field
+data FieldPragma
+  = PragmaExpandModules FilePath [C.ModuleName]
+  | PragmaGlobFiles Glob
+  | PragmaFragment FilePath
+  deriving (Show)
+
+-- | Pragmas affecting global output
+data GlobalPragma
+  = PragmaOptIndent Int
+  | PragmaOptTabular Bool
+  deriving (Show)
+
+-------------------------------------------------------------------------------
+-- Parser
+-------------------------------------------------------------------------------
+
+-- | Parse pragma from 'ByteString'.
+--
+-- An error ('Left') is reported only if input 'ByteString' starts with @-- cabal-gild:@.
+parsePragma :: ByteString -> Either String (Maybe Pragma)
+parsePragma bs = case dropPrefix bs of
+  Nothing -> Right Nothing
+  Just bs' -> bimap show Just $ C.runParsecParser parser "<input>" $ C.fieldLineStreamFromBS bs'
+  where
+    dropPrefix bs0 = do
+      bs1 <- BS.stripPrefix "--" bs0
+      bs2 <- BS.stripPrefix "cabal-gild:" (stripWhitespace bs1)
+      return (stripWhitespace bs2)
+
+    parser :: C.ParsecParser Pragma
+    parser = do
+      t <- C.parsecToken
+      case t of
+        "expand" -> expandModules
+        "indent" -> indent
+        "glob-files" -> globFiles
+        "tabular" -> return $ GlobalPragma $ PragmaOptTabular True
+        "no-tabular" -> return $ GlobalPragma $ PragmaOptTabular False
+        "fragment" -> fragment
+        _ -> fail $ "Unknown pragma " ++ t
+
+    expandModules :: C.ParsecParser Pragma
+    expandModules = do
+      C.spaces
+      dir <- C.parsecToken
+      mns <- C.many (C.space *> C.spaces *> C.char '-' *> C.parsec)
+      return $ FieldPragma $ PragmaExpandModules dir mns
+
+    indent :: C.ParsecParser Pragma
+    indent = do
+      C.spaces
+      GlobalPragma . PragmaOptIndent <$> C.integral
+
+    fragment :: C.ParsecParser Pragma
+    fragment = do
+      C.spaces
+      FieldPragma . PragmaFragment <$> C.parsecToken
+
+    globFiles :: C.ParsecParser Pragma
+    globFiles = do
+      C.spaces
+      t <- C.parsecToken
+      case parseGlob t of
+        Right g -> return $ FieldPragma $ PragmaGlobFiles g
+        Left e -> C.unexpected e
+
+stripWhitespace :: ByteString -> ByteString
+stripWhitespace bs = case BS.uncons bs of
+  Nothing -> bs
+  Just (w, bs')
+    | w == 32 -> stripWhitespace bs'
+    | otherwise -> bs
+
+parsePragmas :: Comments -> ([String], [Pragma])
+parsePragmas = fmap catMaybes . partitionEithers . map parsePragma . unComments
diff --git a/source/library/CabalGild/Prelude.hs b/source/library/CabalGild/Prelude.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Prelude.hs
@@ -0,0 +1,117 @@
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+--
+-- Fat-prelude.
+module CabalGild.Prelude
+  ( -- * Control.Arrow
+    (&&&),
+
+    -- * Control.Monad
+    when,
+    unless,
+    void,
+
+    -- * Data.Bifunctor
+    bimap,
+
+    -- * Data.Char
+    toLower,
+
+    -- * Data.Either
+    partitionEithers,
+
+    -- * Data.Foldable
+    toList,
+    traverse_,
+    asum,
+    for_,
+
+    -- * Data.Function
+    on,
+    (&),
+
+    -- * Data.List
+    intercalate,
+    sortOn,
+    sortBy,
+    nub,
+
+    -- * Data.Maybe
+    catMaybes,
+    fromMaybe,
+    isJust,
+    isNothing,
+
+    -- * Packages
+
+    -- ** bytestring
+    ByteString,
+
+    -- ** Cabal
+    C.fromUTF8BS,
+    C.toUTF8BS,
+    pack',
+    unpack',
+
+    -- ** containers
+    Set,
+
+    -- ** directory
+    dropExtension,
+    splitDirectories,
+
+    -- ** exceptions
+    catchError,
+    throwError,
+
+    -- * Extras
+
+    -- ** Lens
+    traverseOf,
+    over,
+    view,
+    _1,
+
+    -- ** Tuples
+    fstOf3,
+    sndOf3,
+    trdOf3,
+  )
+where
+
+import Control.Arrow ((&&&))
+import Control.Monad (unless, void, when)
+import Control.Monad.Except (catchError, throwError)
+import Data.Bifunctor (bimap)
+import Data.ByteString (ByteString)
+import Data.Char (toLower)
+import Data.Either (partitionEithers)
+import Data.Foldable (asum, for_, toList, traverse_)
+import Data.Function (on, (&))
+import Data.List (intercalate, nub, sortBy, sortOn)
+import Data.Maybe (catMaybes, fromMaybe, isJust, isNothing)
+import Data.Set (Set)
+import Distribution.Compat.Lens (over, view)
+import Distribution.Compat.Newtype (pack', unpack')
+import qualified Distribution.Utils.Generic as C
+import System.FilePath (dropExtension, splitDirectories)
+
+traverseOf ::
+  ((a -> f b) -> s -> f t) ->
+  (a -> f b) ->
+  s ->
+  f t
+traverseOf = id
+
+_1 :: (Functor f) => (a -> f b) -> (a, c) -> f (b, c)
+_1 f (a, c) = (\b -> (b, c)) <$> f a
+
+fstOf3 :: (a, b, c) -> a
+fstOf3 (a, _, _) = a
+
+sndOf3 :: (a, b, c) -> b
+sndOf3 (_, b, _) = b
+
+trdOf3 :: (a, b, c) -> c
+trdOf3 (_, _, c) = c
diff --git a/source/library/CabalGild/Refactoring.hs b/source/library/CabalGild/Refactoring.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Refactoring.hs
@@ -0,0 +1,65 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Refactoring
+  ( CommentsPragmas,
+    refactor,
+  )
+where
+
+import CabalGild.Fields.SourceFiles
+import CabalGild.Monad
+import CabalGild.Refactoring.ExpandExposedModules
+import CabalGild.Refactoring.Fragments
+import CabalGild.Refactoring.GlobFiles
+import CabalGild.Refactoring.Type
+import qualified Distribution.Fields as C
+
+-------------------------------------------------------------------------------
+-- Refactorings
+-------------------------------------------------------------------------------
+
+refactor :: forall m r. (MonadCabalGild r m) => [C.Field CommentsPragmas] -> m [C.Field CommentsPragmas]
+refactor = rewriteFields rewrite
+  where
+    rewrite :: C.Field CommentsPragmas -> m (Maybe (C.Field CommentsPragmas))
+    rewrite f@(C.Field (C.Name _ n) _)
+      | n == "exposed-modules" || n == "other-modules" =
+          combine
+            [ refactoringFragments,
+              refactoringExpandExposedModules
+            ]
+            f
+      | n `elem` fileFields =
+          combine
+            [ refactoringFragments,
+              refactoringGlobFiles
+            ]
+            f
+      | otherwise =
+          combine
+            [ refactoringFragments
+            ]
+            f
+    rewrite f@C.Section {} =
+      combine
+        [ refactoringFragments
+        ]
+        f
+
+-- | Try refactorings in turn,
+-- considering it done if one applies.
+combine ::
+  (Monad m) =>
+  [C.Field CommentsPragmas -> m (Maybe (C.Field CommentsPragmas))] ->
+  C.Field CommentsPragmas ->
+  m (Maybe (C.Field CommentsPragmas))
+combine [] _ = return Nothing
+combine (r : rs) f = do
+  m <- r f
+  case m of
+    Nothing -> combine rs f
+    Just f' -> return (Just f')
diff --git a/source/library/CabalGild/Refactoring/ExpandExposedModules.hs b/source/library/CabalGild/Refactoring/ExpandExposedModules.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Refactoring/ExpandExposedModules.hs
@@ -0,0 +1,49 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RankNTypes #-}
+{-# OPTIONS_GHC -Wno-deprecations #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Refactoring.ExpandExposedModules
+  ( refactoringExpandExposedModules,
+  )
+where
+
+import CabalGild.Monad
+import CabalGild.Pragma
+import CabalGild.Prelude
+import CabalGild.Refactoring.Type
+import qualified Distribution.Fields as C
+import qualified Distribution.ModuleName as C
+
+refactoringExpandExposedModules :: FieldRefactoring
+refactoringExpandExposedModules C.Section {} = pure Nothing
+refactoringExpandExposedModules (C.Field name@(C.Name (_, _, pragmas) _n) fls) = do
+  dirs <- parse pragmas
+  files <- traverseOf (traverse . _1) getFiles dirs
+
+  let newModules :: [C.FieldLine CommentsPragmas]
+      newModules =
+        catMaybes
+          [ return $ C.FieldLine emptyCommentsPragmas $ toUTF8BS $ intercalate "." parts
+            | (files', mns) <- files,
+              file <- files',
+              let parts = splitDirectories $ dropExtension file,
+              all C.validModuleComponent parts,
+              let mn = C.fromComponents parts, -- TODO: don't use fromComponents
+              mn `notElem` mns
+          ]
+
+  pure $ case newModules of
+    [] -> Nothing
+    _ -> Just (C.Field name (newModules ++ fls))
+  where
+    parse :: (MonadCabalGild r m) => [FieldPragma] -> m [(FilePath, [C.ModuleName])]
+    parse = fmap mconcat . traverse go
+      where
+        go :: (MonadCabalGild r m) => FieldPragma -> m [(FilePath, [C.ModuleName])]
+        go (PragmaExpandModules fp mns) = return [(fp, mns)]
+        go p = do
+          displayWarning $ "Skipped pragma " ++ show p
+          return []
diff --git a/source/library/CabalGild/Refactoring/Fragments.hs b/source/library/CabalGild/Refactoring/Fragments.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Refactoring/Fragments.hs
@@ -0,0 +1,88 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RankNTypes #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Refactoring.Fragments
+  ( refactoringFragments,
+  )
+where
+
+import CabalGild.Comments
+import CabalGild.Monad
+import CabalGild.Parser
+import CabalGild.Pragma
+import CabalGild.Prelude
+import CabalGild.Refactoring.Type
+import qualified Distribution.Fields as C
+import qualified Distribution.Fields.Field as C
+import qualified Distribution.Fields.Pretty as C
+import qualified Distribution.Parsec as C
+import Text.PrettyPrint (hsep, render)
+
+-- | Expand fragments.
+--
+-- Applies to all fields and sections
+refactoringFragments :: FieldRefactoring
+refactoringFragments field = do
+  mp <- parse (getPragmas field)
+  case mp of
+    Nothing -> pure Nothing
+    Just p ->
+      readFileBS p >>= \mcontents -> case mcontents of
+        NoIO -> pure Nothing
+        IOError err -> do
+          displayWarning $ "Fragment " ++ p ++ " failed to read: " ++ show err
+          pure Nothing
+        Contents c -> do
+          fields <- parseFields c
+          case (field, fields) of
+            (_, []) -> do
+              displayWarning $ "Fragment " ++ p ++ " is empty."
+              pure Nothing
+            (C.Field (C.Name _ n) _, C.Section name@(C.Name _ _) arg _ : _) -> do
+              displayWarning $ "Fragment " ++ p ++ " contains a section " ++ showSection name arg ++ ", expecting field " ++ show n ++ "."
+              pure Nothing
+            (C.Section name@(C.Name _ _) arg _, C.Field (C.Name _ n') _ : _) -> do
+              displayWarning $ "Fragment " ++ p ++ " contains a field " ++ show n' ++ ", expecting section " ++ showSection name arg ++ "."
+              pure Nothing
+            (C.Field name@(C.Name _ n) _, C.Field (C.Name _ n') fls' : rest) -> do
+              unless (null rest) $
+                displayWarning $
+                  "Fragment " ++ p ++ " contains multiple fields or sections, using only the first."
+              if n == n'
+                then do
+                  -- everything is fine, replace
+                  pure (Just (C.Field name (noCommentsPragmas fls')))
+                else do
+                  displayWarning $ "Fragment " ++ p ++ " contains field " ++ show n' ++ ", expecting field " ++ show n ++ "."
+                  pure Nothing
+            (C.Section name@(C.Name _ _) arg _, C.Section name'@(C.Name _ _) arg' fs' : rest) -> do
+              unless (null rest) $
+                displayWarning $
+                  "Fragment " ++ p ++ " contains multiple fields or sections, using only the first."
+
+              if void name == void name' && map void arg == map void arg'
+                then do
+                  pure (Just (C.Section name arg (noCommentsPragmas fs')))
+                else do
+                  displayWarning $ "Fragment " ++ p ++ " contains a section " ++ showSection name arg ++ ", expecting section " ++ showSection name' arg' ++ "."
+                  pure Nothing
+  where
+    noCommentsPragmas :: (Functor f) => [f ann] -> [f CommentsPragmas]
+    noCommentsPragmas = map ((C.zeroPos, Comments [], []) <$)
+
+    getPragmas :: C.Field CommentsPragmas -> [FieldPragma]
+    getPragmas = trdOf3 . C.fieldAnn
+
+    showSection :: C.Name ann -> [C.SectionArg ann] -> String
+    showSection (C.Name _ n) [] = show n
+    showSection (C.Name _ n) args = show (fromUTF8BS n ++ " " ++ render (hsep (C.prettySectionArgs n args)))
+
+    parse :: (MonadCabalGild r m) => [FieldPragma] -> m (Maybe FilePath)
+    parse = fmap asum . traverse go
+      where
+        go :: (Monad m) => FieldPragma -> m (Maybe FilePath)
+        go (PragmaFragment f) = return (Just f)
+        go _ = return Nothing
diff --git a/source/library/CabalGild/Refactoring/GlobFiles.hs b/source/library/CabalGild/Refactoring/GlobFiles.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Refactoring/GlobFiles.hs
@@ -0,0 +1,53 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RankNTypes #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Refactoring.GlobFiles
+  ( refactoringGlobFiles,
+  )
+where
+
+import CabalGild.Glob
+import CabalGild.Monad
+import CabalGild.Pragma
+import CabalGild.Prelude
+import CabalGild.Refactoring.Type
+import qualified Distribution.Fields as C
+import qualified System.FilePath as Native
+import qualified System.FilePath.Posix as Posix
+
+refactoringGlobFiles :: FieldRefactoring
+refactoringGlobFiles C.Section {} = pure Nothing
+refactoringGlobFiles (C.Field name@(C.Name (_, _, pragmas) _n) fls) = do
+  globs <- parse pragmas
+  files <- fmap concat (traverse match' globs)
+
+  let newFiles :: [C.FieldLine CommentsPragmas]
+      newFiles =
+        catMaybes
+          [ return $ C.FieldLine emptyCommentsPragmas $ toUTF8BS file
+            | file <- files
+          ]
+
+  pure $ case files of
+    [] -> Nothing
+    _ -> Just (C.Field name (newFiles ++ fls))
+  where
+    parse :: (MonadCabalGild r m) => [FieldPragma] -> m [Glob]
+    parse = fmap mconcat . traverse go
+      where
+        go :: (MonadCabalGild r m) => FieldPragma -> m [Glob]
+        go (PragmaGlobFiles g) = return [g]
+        go p = do
+          displayWarning $ "Skipped pragma " ++ show p
+          return []
+
+    match' :: (MonadCabalGild r m) => Glob -> m [FilePath]
+    match' g@(Glob dir _) = do
+      files <- map (dir Native.</>) <$> getFiles dir
+      return $ map toPosix $ filter (match g) files
+
+    toPosix :: FilePath -> FilePath
+    toPosix = Posix.joinPath . Native.splitDirectories
diff --git a/source/library/CabalGild/Refactoring/Type.hs b/source/library/CabalGild/Refactoring/Type.hs
new file mode 100644
--- /dev/null
+++ b/source/library/CabalGild/Refactoring/Type.hs
@@ -0,0 +1,54 @@
+{-# LANGUAGE RankNTypes #-}
+
+-- |
+-- License: GPL-3.0-or-later
+-- Copyright: Oleg Grenrus
+module CabalGild.Refactoring.Type
+  ( FieldRefactoring,
+    CommentsPragmas,
+    emptyCommentsPragmas,
+    rewriteFields,
+  )
+where
+
+import CabalGild.Comments
+import CabalGild.Monad
+import CabalGild.Pragma
+import qualified Distribution.Fields as C
+import qualified Distribution.Parsec as C
+
+-------------------------------------------------------------------------------
+-- Refactoring type
+-------------------------------------------------------------------------------
+
+type CommentsPragmas = (C.Position, Comments, [FieldPragma])
+
+emptyCommentsPragmas :: CommentsPragmas
+emptyCommentsPragmas = (C.zeroPos, mempty, mempty)
+
+type FieldRefactoring =
+  forall r m.
+  (MonadCabalGild r m) =>
+  (C.Field CommentsPragmas -> m (Maybe (C.Field CommentsPragmas)))
+
+-------------------------------------------------------------------------------
+-- Traversing refactoring
+-------------------------------------------------------------------------------
+
+-- | A top-to-bottom rewrite of sections and fields
+rewriteFields ::
+  (MonadCabalGild r m) =>
+  (C.Field CommentsPragmas -> m (Maybe (C.Field CommentsPragmas))) ->
+  [C.Field CommentsPragmas] ->
+  m [C.Field CommentsPragmas]
+rewriteFields f = goMany
+  where
+    goMany = traverse go
+
+    go x = do
+      m <- f x
+      case m of
+        Just y -> return y
+        Nothing -> case x of
+          C.Field {} -> return x
+          C.Section name args fs -> C.Section name args <$> goMany fs
diff --git a/source/library/VersionInterval.hs b/source/library/VersionInterval.hs
new file mode 100644
--- /dev/null
+++ b/source/library/VersionInterval.hs
@@ -0,0 +1,448 @@
+{-# LANGUAGE BangPatterns #-}
+
+-- |
+--
+-- Author:          Oleg Grenrus <oleg.grenrus@iki.fi>
+-- SPDX-License-Id: GPL-2.0-or-later
+--
+-- This module implements a view of a 'VersionRange' as a finite
+-- list of separated version intervals.
+--
+-- In conversion from and to 'VersionRange' it makes some effort to
+-- preserve the caret operator @^>=x.y@.  This constraint a priori
+-- specifies the same interval as @==x.y.*@, but indicates that newer
+-- versions could be acceptable (@allow-newer: ^@).
+module VersionInterval
+  ( -- * Version intervals
+    VersionIntervals,
+
+    -- * Conversions
+    toVersionIntervals,
+    fromVersionIntervals,
+    ConversionProblem (..),
+
+    -- ** Normalisation
+    normaliseVersionRange,
+
+    -- * Version intervals view
+    VersionInterval (..),
+    LB (..),
+    MB (..),
+    UB (..),
+    Bound (..),
+
+    -- * For testing
+    validVersionInterval,
+    validVersionIntervals,
+    intersectInterval,
+    stage1,
+    stage2,
+    stage3,
+  )
+where
+
+import Control.Monad (join)
+import Data.List (sortOn)
+import Data.List.NonEmpty (NonEmpty (..), cons)
+import Data.Maybe (catMaybes)
+import Distribution.Types.Version
+  ( Version,
+    mkVersion,
+    validVersion,
+    version0,
+    versionNumbers,
+  )
+import Distribution.Types.VersionRange.Internal
+  ( VersionRange,
+    VersionRangeF (..),
+    cataVersionRange,
+    earlierVersion,
+    intersectVersionRanges,
+    majorBoundVersion,
+    majorUpperBound,
+    noVersion,
+    orLaterVersion,
+    thisVersion,
+    unionVersionRanges,
+  )
+
+singleton :: a -> NonEmpty a
+singleton x = x :| []
+
+-------------------------------------------------------------------------------
+-- Data
+-------------------------------------------------------------------------------
+
+-- | A complementary representation of a 'VersionRange'. Instead of a boolean
+-- version predicate it uses an increasing sequence of non-overlapping,
+-- non-empty intervals.
+--
+-- This version is different than in @Cabal-3.8@ and previous,
+-- as it tries to preserve @^>=@ version ranges under default and @transformCaretUpper@ semantics.
+-- Slighly simplifying, 'normalizeVersionRange' shouldn't destroy @^>=@ in version range expressions.
+newtype VersionIntervals = VersionIntervals [VersionInterval]
+  deriving (Eq, Show)
+
+-- | Version interval.
+--
+-- Invariants:
+--
+-- * Interval is non-empty
+-- * 'MB' is between 'LB' and 'UB'.
+data VersionInterval = VI !LB !MB !UB
+  deriving (Eq, Show)
+
+-- | Lower bound. For intervals it always exist: 'zeroLB' i.e. @>= 0@.
+--
+-- All lower bound intervals are inclusive, i.e. @>=v@. @>x.y.z@ is converted into @>=x.y.z.0@.
+newtype LB = LB Version
+  deriving (Eq, Ord, Show)
+
+-- | Upper bound.
+--
+-- All upper bounds are exclusive, i.e. @<v@. @<=x.y.z@ is converted to @<x.y.z.0@.
+data UB
+  = -- | upper bound
+    UB !Version
+  | -- | no upper bound (i.e. infinite)
+    NoUB
+  deriving (Eq, Ord, Show)
+
+-- | Bound variant.
+data Bound
+  = -- | inclusive: @>=@ or @<=@
+    Incl
+  | -- | exclusive: @>@ or @<@
+    Excl
+  deriving (Eq, Ord, Show)
+
+-- | Middle bound.
+data MB
+  = -- | major bound.
+    MB !Version
+  | -- | no major bound (i.e. infinite)
+    NoMB
+  deriving (Eq, Ord, Show)
+
+-- | @>=0@
+zeroLB :: LB
+zeroLB = LB version0
+
+-- | Whether the version is @0@.
+isVersion0 :: Version -> Bool
+isVersion0 = (==) version0
+
+-- | Versions are not separated type.
+succVersion :: Version -> Version
+succVersion v = mkVersion (versionNumbers v ++ [0])
+
+-------------------------------------------------------------------------------
+-- Stage1
+-------------------------------------------------------------------------------
+
+stage1 :: ([VersionInterval] -> [VersionInterval]) -> VersionRange -> [VersionInterval]
+stage1 opt = cataVersionRange alg
+  where
+    -- version range leafs transform into singleton intervals
+    alg (ThisVersionF v) = [VI (LB v) (MB (succVersion v)) (UB (succVersion v))]
+    alg (LaterVersionF v) = [VI (LB (succVersion v)) NoMB NoUB]
+    alg (OrLaterVersionF v) = [VI (LB v) NoMB NoUB]
+    alg (EarlierVersionF v)
+      | isVersion0 v = []
+      | otherwise = [VI zeroLB (MB v) (UB v)]
+    alg (OrEarlierVersionF v) = [VI zeroLB (MB (succVersion v)) (UB (succVersion v))]
+    -- \^>= version-range's upper bound should be MajorBound
+    alg (MajorBoundVersionF v) = [VI (LB v) (MB (majorUpperBound v)) NoUB]
+    -- union: just merge the version intervals
+    alg (UnionVersionRangesF v1 v2) = v1 ++ v2
+    -- intersection: pairwise intersect. Strip empty intervals. Sort to restore the invariant.
+    alg (IntersectVersionRangesF v1 v2) = catMaybes $ intersectInterval <$> opt v1 <*> opt v2
+
+-------------------------------------------------------------------------------
+-- Stage2
+-------------------------------------------------------------------------------
+
+stage2 :: [VersionInterval] -> [VersionInterval]
+stage2 = sortOn (\(VI l _ _) -> l)
+
+-------------------------------------------------------------------------------
+-- Postprocess
+-------------------------------------------------------------------------------
+
+stage2and3 :: [VersionInterval] -> [VersionInterval]
+stage2and3 = stage3 . stage2
+
+stage3 :: [VersionInterval] -> [VersionInterval]
+stage3 [] = []
+stage3 (VI l m u : rest) = stage3go l m u rest
+
+stage3go :: LB -> MB -> UB -> [VersionInterval] -> [VersionInterval]
+stage3go l m u [] = [VI l m u]
+stage3go l m u (VI l' m' u' : is)
+  | l == l' = stage3go l' (unionMB m m') (unionUB u u') is
+  | otherwise = case overlap m u l' of
+      NoOverlap -> VI l m u : stage3go l' m' u' is
+      OverlapU -> viCons (VI l m (trimLB u l')) (stage3go l' m' (unionUB u u') is)
+      OverlapM -> stage3go l (unionMB m m') (unionUB u u') is
+  where
+    viCons :: VersionInterval -> [VersionInterval] -> [VersionInterval]
+    viCons i | nonEmptyVI i = (i :)
+    viCons _ = id
+
+trimLB :: UB -> LB -> UB
+trimLB _ (LB l) = UB l
+
+-------------------------------------------------------------------------------
+-- Intersections
+-------------------------------------------------------------------------------
+
+intersectInterval :: VersionInterval -> VersionInterval -> Maybe VersionInterval
+intersectInterval (VI xl xm xu) (VI yl ym yu)
+  | nonEmptyVI xy = Just xy
+  | otherwise = Nothing
+  where
+    l = intersectLB xl yl
+    m = intersectMB xm ym
+    u = intersectUB xu yu
+
+    -- make middle bound be between l and u
+    m' = rtrimMB (ltrimMB l m) u
+
+    xy = VI l m' u
+
+ltrimMB :: LB -> MB -> MB
+ltrimMB _ NoMB = NoMB
+ltrimMB (LB l) (MB m) = case compare l m of
+  LT -> MB m
+  EQ -> MB m
+  GT -> MB l
+
+rtrimMB :: MB -> UB -> MB
+rtrimMB m NoUB = m
+rtrimMB NoMB (UB u) = MB u
+rtrimMB (MB m) (UB u) = MB (min m u)
+
+intersectLB :: LB -> LB -> LB
+intersectLB (LB v) (LB u) = LB (max v u)
+
+intersectMB :: MB -> MB -> MB
+intersectMB NoMB b = b
+intersectMB b NoMB = b
+intersectMB (MB v) (MB u) = MB (min v u)
+
+intersectUB :: UB -> UB -> UB
+intersectUB NoUB b = b
+intersectUB b NoUB = b
+intersectUB (UB v) (UB u) = UB (min v u)
+
+intersectMBandUB :: MB -> UB -> UB
+intersectMBandUB NoMB b = b
+intersectMBandUB (MB v) NoUB = UB v
+intersectMBandUB (MB v) (UB u) = UB (min v u)
+
+-------------------------------------------------------------------------------
+-- Unions
+-------------------------------------------------------------------------------
+
+unionMB :: MB -> MB -> MB
+unionMB NoMB _ = NoMB
+unionMB _ NoMB = NoMB
+unionMB (MB v) (MB u) = MB (max v u)
+
+unionUB :: UB -> UB -> UB
+unionUB NoUB _ = NoUB
+unionUB _ NoUB = NoUB
+unionUB (UB v) (UB u) = UB (max v u)
+
+-------------------------------------------------------------------------------
+-- Helpers
+-------------------------------------------------------------------------------
+
+-- | Overlaps.
+data Overlap
+  = -- | no overlap, next interval's @l@ is greater than @u@
+    NoOverlap
+  | -- | overlaps, next interval's @l@ is less than @m@
+    OverlapM
+  | -- | overlaps, next interval's @l@ is less than @u@ (but greater than @m@)
+    OverlapU
+  deriving (Eq, Show)
+
+overlap :: MB -> UB -> LB -> Overlap
+overlap _ (UB u) (LB l) | u < l = NoOverlap
+overlap (MB m) _ (LB l) | m < l = OverlapU
+overlap _ _ _ = OverlapM
+
+-------------------------------------------------------------------------------
+-- Invariants
+-------------------------------------------------------------------------------
+
+-- | 'VersionIntervals' invariant:
+--
+-- * all intervals are valid (lower bound is less then upper bound, middle bound is in between)
+-- * intervals doesn't touch each other (distinct)
+validVersionIntervals :: VersionIntervals -> Bool
+validVersionIntervals (VersionIntervals intervals) =
+  all validVersionInterval intervals
+    && all doesNotTouch' (pairs intervals)
+  where
+    doesNotTouch' :: (VersionInterval, VersionInterval) -> Bool
+    doesNotTouch' (VI l m u, VI l' _ _) =
+      l < l' && case overlap m u l' of
+        NoOverlap -> True
+        OverlapM -> False
+        OverlapU -> case u of
+          NoUB -> True
+          UB uv -> case l' of LB lv -> uv == lv
+
+pairs :: [a] -> [(a, a)]
+pairs xs = zip xs (drop 1 xs)
+
+validLB :: LB -> Bool
+validLB (LB v) = validVersion v
+
+validUB :: UB -> Bool
+validUB NoUB = True
+validUB (UB v) = validVersion v
+
+validMB :: MB -> Bool
+validMB NoMB = True
+validMB (MB v) = validVersion v
+
+validVersionInterval :: VersionInterval -> Bool
+validVersionInterval i@(VI l m u) = validLB l && validMB m && validUB u && nonEmptyVI i && lbLessThanMB l m && mbLessThanUB m u
+
+mbLessThanUB :: MB -> UB -> Bool
+mbLessThanUB (MB m) (UB u) = m <= u
+mbLessThanUB NoMB (UB _) = False
+mbLessThanUB _ NoUB = True
+
+lbLessThanMB :: LB -> MB -> Bool
+lbLessThanMB _ NoMB = True
+lbLessThanMB (LB l) (MB m) = l <= m
+
+-- Check an interval is non-empty
+--
+nonEmptyVI :: VersionInterval -> Bool
+nonEmptyVI (VI (LB _) _ NoUB) = True
+nonEmptyVI (VI (LB l) _ (UB u)) = l < u
+
+-------------------------------------------------------------------------------
+-- Conversions
+-------------------------------------------------------------------------------
+
+-- | Convert a 'VersionRange' to a sequence of version intervals.
+toVersionIntervals :: VersionRange -> VersionIntervals
+toVersionIntervals = VersionIntervals . stage2and3 . stage1 stage2and3
+
+data ConversionProblem
+  = IntervalsEmpty
+  | OtherConversionProblem
+  deriving (Eq, Show)
+
+-- | Convert a 'VersionIntervals' value back into a 'VersionRange' expression
+-- representing the version intervals.
+fromVersionIntervals :: VersionIntervals -> Either ConversionProblem VersionRange
+fromVersionIntervals (VersionIntervals []) = Right noVersion
+fromVersionIntervals (VersionIntervals (x : xs)) =
+  case join <$> traverse intervalToVersionRange (preprocess x xs) of
+    Just vrs -> Right (foldr1 unionVersionRanges vrs)
+    Nothing ->
+      Left $
+        if all seemsEmpty (x : xs)
+          then IntervalsEmpty
+          else OtherConversionProblem
+  where
+    -- we can remove upper bounds, if they touch next interval, and the next interval doesn't have upper bound
+    preprocess :: VersionInterval -> [VersionInterval] -> NonEmpty VersionInterval
+    preprocess i [] = i :| []
+    preprocess i@(VI l m u) (j : js) = case u' of
+      NoUB | touchesUB u l' -> cons (VI l m NoUB) js'
+      _ -> cons i js'
+      where
+        js'@(VI l' _ u' :| _) = preprocess j js
+
+    seemsEmpty :: VersionInterval -> Bool
+    seemsEmpty (VI l m u) = not (nonEmptyVI (VI l NoMB (intersectMBandUB m u)))
+
+touchesUB :: UB -> LB -> Bool
+touchesUB NoUB _ = True
+touchesUB (UB u) (LB l) = u >= l
+
+lbToVR :: LB -> VersionRange
+lbToVR (LB l) = orLaterVersion l
+
+ubToVR :: UB -> VersionRange -> VersionRange
+ubToVR NoUB vr = vr
+ubToVR (UB u) vr = intersectVersionRanges vr (earlierVersion u)
+
+mbEqUB :: MB -> UB -> Bool
+mbEqUB NoMB NoUB = True
+mbEqUB NoMB (UB _) = False
+mbEqUB (MB m) (UB u) = m == u
+mbEqUB (MB _) NoUB = False
+
+-- return the unions of version ranges.
+intervalToVersionRange :: VersionInterval -> Maybe (NonEmpty VersionRange)
+intervalToVersionRange (VI l m u) | mbEqUB m u = Just (singleton (intervalToVersionRange1 l u))
+intervalToVersionRange (VI l m u) = fmap (fmap (ubToVR u)) (intervalToVersionRange2 l m)
+
+intervalToVersionRange1 :: LB -> UB -> VersionRange
+intervalToVersionRange1 (LB v) upper' = case upper' of
+  NoUB ->
+    lowerBound
+  UB u
+    | succVersion v == u ->
+        thisVersion v
+  UB u -> withLowerBound (makeUpperBound u)
+  where
+    lowerBound :: VersionRange
+    lowerBound = lbToVR (LB v)
+
+    withLowerBound :: VersionRange -> VersionRange
+    withLowerBound vr
+      | isVersion0 v = vr
+      | otherwise = intersectVersionRanges lowerBound vr
+
+    makeUpperBound :: Version -> VersionRange
+    makeUpperBound = earlierVersion
+
+intervalToVersionRange2 :: LB -> MB -> Maybe (NonEmpty VersionRange)
+intervalToVersionRange2 (LB l) NoMB = Just (singleton lowerBound)
+  where
+    lowerBound :: VersionRange
+    lowerBound = lbToVR (LB l)
+intervalToVersionRange2 (LB l) (MB m)
+  | supermajor l == supermajor m =
+      go (l :|) (majorUpperBound l)
+  | [a, b] <- versionNumbers m,
+    let m' = mkVersion [a, b - 1],
+    b >= 1,
+    m' > l =
+      Just $
+        ubToVR (UB m') (lbToVR (LB l))
+          :| [majorBoundVersion (mkVersion [a, b - 1])]
+  | otherwise =
+      Nothing
+  where
+    go :: ([Version] -> NonEmpty Version) -> Version -> Maybe (NonEmpty VersionRange)
+    go !acc v = case compare v m of
+      LT -> go (snoc acc v) (majorUpperBound v)
+      EQ -> Just (fmap majorBoundVersion (acc []))
+      GT -> Nothing
+
+    snoc :: ([a] -> c) -> a -> [a] -> c
+    snoc xs x = xs . (x :)
+
+    supermajor :: Version -> Int
+    supermajor v = case versionNumbers v of
+      [] -> -1
+      s : _ -> s
+
+-------------------------------------------------------------------------------
+-- Normalisation
+-------------------------------------------------------------------------------
+
+-- | Convert 'VersionRange' to 'VersionIntervals' and back.
+normaliseVersionRange :: VersionRange -> Either ConversionProblem VersionRange
+normaliseVersionRange = fromVersionIntervals . toVersionIntervals
diff --git a/source/test-suite/CabalGild/Test/Golden.hs b/source/test-suite/CabalGild/Test/Golden.hs
new file mode 100644
--- /dev/null
+++ b/source/test-suite/CabalGild/Test/Golden.hs
@@ -0,0 +1,87 @@
+module CabalGild.Test.Golden (tests) where
+
+import CabalGild (cabalGild)
+import CabalGild.Monad (runCabalGild)
+import CabalGild.Options (defaultOptions)
+import CabalGild.Prelude
+import qualified Control.Exception as Exception
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Char8 as BS8
+import qualified Data.Map as Map
+import System.FilePath ((-<.>), (</>))
+import Test.Tasty (TestTree, testGroup)
+import qualified Test.Tasty.HUnit as HUnit
+
+tests :: TestTree
+tests =
+  testGroup
+    "tests"
+    [ goldenTest' "cabal-fmt",
+      goldenTest' "Cabal",
+      goldenTest' "Cabal-notab",
+      goldenTest' "simple-example",
+      goldenTest' "tree-diff",
+      goldenTest' "fragment-missing",
+      goldenTest' "fragment-empty",
+      goldenTest' "fragment-wrong-field",
+      goldenTest' "fragment-wrong-type",
+      goldenTest' "fragment-multiple",
+      goldenTest' "fragment-section",
+      goldenTest' "issue69",
+      goldenTest' "issue29"
+    ]
+
+goldenTest' :: String -> TestTree
+goldenTest' n =
+  testGroup
+    n
+    [ HUnit.testCase "successfully formats" $ do
+        input <- BS.readFile inputPath
+        (output, warnings) <-
+          either Exception.throwIO pure
+            . runCabalGild files defaultOptions
+            $ cabalGild inputPath input
+        expected <- readFile goldenPath
+        let actual = unlines (fmap ("-- " <>) warnings) <> output
+        actual HUnit.@?= expected,
+      HUnit.testCase "round trips" $ do
+        input <- BS.readFile inputPath
+        (expected, _) <-
+          either Exception.throwIO pure
+            . runCabalGild files defaultOptions
+            $ cabalGild inputPath input
+        (actual, _) <-
+          either Exception.throwIO pure
+            . runCabalGild files defaultOptions
+            . cabalGild inputPath
+            $ toUTF8BS expected
+        actual HUnit.@?= expected
+    ]
+  where
+    goldenPath = "fixtures" </> n -<.> "format"
+    inputPath = "fixtures" </> n -<.> "cabal"
+
+files :: Map.Map FilePath BS.ByteString
+files =
+  Map.fromList
+    [ p "empty.fragment" "",
+      p
+        "build-depends.fragment"
+        "build-depends: base, doctest >=0.15 && <0.17, QuickCheck >=2.12 && <2.13, simple-example, template-haskell",
+      p
+        "tested-with.fragment"
+        "tested-with: GHC ==8.0.2",
+      p
+        "common.fragment"
+        "common deps\n  build-depends: base, bytestring, containers\n  ghc-options: -Wall",
+      p
+        "multiple.fragment"
+        "build-depends: base\nghc-options: -Wall",
+      p ("cbits" </> "header.h") "...",
+      p ("cbits" </> "source1.c") "...",
+      p ("cbits" </> "source2.c") "...",
+      p ("cbits" </> "sub" </> "source3.c") "..."
+    ]
+  where
+    p :: a -> String -> (a, ByteString)
+    p x y = (x, BS8.pack y)
diff --git a/source/test-suite/CabalGild/Test/Interval.hs b/source/test-suite/CabalGild/Test/Interval.hs
new file mode 100644
--- /dev/null
+++ b/source/test-suite/CabalGild/Test/Interval.hs
@@ -0,0 +1,385 @@
+{-# OPTIONS_GHC -Wno-orphans #-}
+
+module CabalGild.Test.Interval where
+
+import Control.Monad (replicateM)
+import Distribution.Parsec (eitherParsec)
+import Distribution.Types.Version
+  ( Version,
+    mkVersion,
+    validVersion,
+    versionNumbers,
+  )
+import Distribution.Types.VersionRange
+  ( VersionRange,
+    VersionRangeF (..),
+    anyVersion,
+    earlierVersion,
+    intersectVersionRanges,
+    laterVersion,
+    majorBoundVersion,
+    notThisVersion,
+    orEarlierVersion,
+    orLaterVersion,
+    projectVersionRange,
+    thisVersion,
+    unionVersionRanges,
+    withinRange,
+    withinVersion,
+  )
+import Distribution.Version (transformCaretUpper)
+import Math.NumberTheory.Logarithms (intLog2)
+import Test.QuickCheck (Arbitrary (..), (===))
+import qualified Test.QuickCheck as QC
+import Test.Tasty (TestTree, testGroup)
+import Test.Tasty.HUnit (testCase, (@?=))
+import Test.Tasty.QuickCheck (testProperty)
+import VersionInterval
+
+tests :: TestTree
+tests =
+  testGroup
+    "version-interval"
+    [ testGroup
+        "Validity"
+        [ testProperty "validVersion" validVersion,
+          testProperty "validVersionInterval" validVersionInterval,
+          testProperty "validVersionIntervals" $ \vr ->
+            let intervals = toVersionIntervals vr
+             in QC.counterexample (show intervals) $ validVersionIntervals intervals
+        ],
+      testGroup
+        "VersionInterval"
+        [ testProperty "intersect valid" $ \a b ->
+            let ab = intersectInterval a b
+             in maybe (QC.property True) (\ab' -> QC.counterexample ("intersection: " ++ show ab') $ validVersionInterval ab') ab,
+          testProperty "intersect complete" intersectComplete,
+          testProperty "intersect complete lax" intersectCompleteLax
+        ],
+      testGroup
+        "stage1"
+        [ testProperty "valid" stage1_valid,
+          testProperty "complete" stage1_complete,
+          testProperty "complete lax" stage1_complete_lax,
+          testProperty "valid ex1" $
+            stage1_valid
+              (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (thisVersion (mkVersion [1]))),
+          testProperty "valid ex2" $
+            stage1_valid
+              (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (orLaterVersion (mkVersion [1]))),
+          testProperty "complete ex1" $
+            stage1_complete
+              (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (thisVersion (mkVersion [6])))
+              (mkVersion [6]),
+          testProperty "complete ex2" $
+            stage1_complete
+              (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (orLaterVersion (mkVersion [1]))),
+          testProperty "complete lax ex2" $
+            stage1_complete_lax
+              (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (orLaterVersion (mkVersion [1])))
+        ],
+      testGroup
+        "stage2"
+        [ testProperty "valid" stage2_valid,
+          testProperty "involutive" stage2_involutive,
+          testProperty "complete" stage2_complete,
+          testProperty "complete_lax" stage2_complete_lax
+        ],
+      testGroup
+        "stage3"
+        [ testProperty "valid" stage3_valid,
+          testProperty "involutive" stage3_involutive,
+          testProperty "complete" stage3_complete,
+          testProperty "complete_lax" stage3_complete_lax,
+          testProperty "complete ex1" $
+            stage3_complete
+              [VI (LB (mkVersion [0])) (MB (mkVersion [0])) NoUB, VI (LB (mkVersion [0, 0])) NoMB NoUB]
+              (mkVersion [0]),
+          testProperty "complete lax ex1" $
+            stage3_complete_lax
+              [VI (LB (mkVersion [0, 0])) (MB (mkVersion [0])) (UB (mkVersion [1])), VI (LB (mkVersion [0, 0, 0])) (MB (mkVersion [1])) (UB (mkVersion [1]))]
+              (mkVersion [1]),
+          testProperty "valid ex2" $
+            stage3_valid
+              (stage1 id (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (orLaterVersion (mkVersion [1])))),
+          testProperty "complete ex2" $
+            stage3_complete
+              (stage1 id (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (orLaterVersion (mkVersion [1])))),
+          testProperty "complete lax ex2" $
+            stage3_complete_lax
+              (stage1 id (intersectVersionRanges (majorBoundVersion (mkVersion [0])) (orLaterVersion (mkVersion [1])))),
+          testProperty "valid ex3" $
+            stage3_valid
+              [VI (LB (mkVersion [0, 0])) (MB (mkVersion [0])) NoUB, VI (LB (mkVersion [0, 0])) NoMB NoUB]
+        ],
+      testGroup
+        "normalise"
+        [ normaliseExample ">=1 && <2" ">=1 && <2",
+          normaliseExample "^>=1" "^>=1",
+          normaliseExample "^>=1 || ^>=2" "^>=1 || ^>=2",
+          normaliseExample "^>=1.2 || ^>=1.3 || ^>=1.4" "^>=1.2 || ^>=1.3 || ^>=1.4",
+          normaliseExample "^>=1.2 || ^>=2.0" "^>=1.2 || ^>=2.0",
+          normaliseExample ">=1.2 && <1.4 || ^>=1.4 || ^>=1.5" "^>=1.2 || ^>=1.3 || ^>=1.4 || ^>=1.5",
+          normaliseExample ">=1.2 && <2.4 || ^>=2.4 || ^>=2.5" ">=1.2 && <2.5 || ^>=2.5",
+          normaliseExample "^>=1.2.0.0 || ^>=1.3.0.0 || ^>=1.4.0.0" "^>=1.2.0.0 || ^>=1.3.0.0 || ^>=1.4.0.0",
+          normaliseExample "==3.1.4" "==3.1.4",
+          normaliseExample "<3.1.4 || >3.1.4" "<3.1.4 || >=3.1.4.0",
+          normaliseExample "^>=1.2 && <2.0 || ^>=2.0" "^>=1.2 || ^>=2.0",
+          normaliseExample "^>=1.2 && <3.0 || ^>=2.0" "^>=1.2 || ^>=2.0",
+          normaliseExample "^>=1.2 || ^>=2.0 && <3" "^>=1.2 || ^>=2.0",
+          normaliseExample "(^>=1.2 || ^>=2.0) && <3" "^>=1.2 && <2.0 || ^>=2.0 && <3",
+          normaliseExample "(>=1.2 || >=2.0) && <3" ">=1.2 && <3",
+          normaliseExample "<1 || >=1.0" "<1 || >=1.0",
+          normaliseExample "<=1 || >=1.0" ">=0",
+          normaliseExample ">0 && <0.0" "<0",
+          normaliseExample
+            "^>=1.5.0.1 || ^>=1.6.0.1 || >=1.9 && <1.13"
+            "^>=1.5.0.1 || ^>=1.6.0.1 || ^>=1.9 || ^>=1.10 || ^>=1.11 ||^>=1.12",
+          cannotNormaliseExample "^>=0 && >=0.1" IntervalsEmpty,
+          testProperty "involutive" normaliseInvolutive,
+          testProperty "complete" normaliseComplete,
+          testProperty "complete_lax" normaliseCompleteLax,
+          testProperty "involutive ex1" $
+            normaliseInvolutive $
+              intersectVersionRanges (majorBoundVersion (mkVersion [3])) (laterVersion (mkVersion [3]))
+        ]
+    ]
+
+normaliseExample :: String -> String -> TestTree
+normaliseExample input expected = testCase input $ do
+  input' <- either fail return $ eitherParsec input
+  expected' <- either fail return $ eitherParsec expected
+
+  VersionInterval.normaliseVersionRange input' @?= Right expected'
+
+cannotNormaliseExample :: String -> ConversionProblem -> TestTree
+cannotNormaliseExample input problem = testCase ("cannot " ++ input) $ do
+  input' <- either fail return $ eitherParsec input
+
+  VersionInterval.normaliseVersionRange input' @?= Left problem
+
+-------------------------------------------------------------------------------
+-- Intersect
+-------------------------------------------------------------------------------
+
+intersectComplete :: VersionInterval -> VersionInterval -> Version -> QC.Property
+intersectComplete a b v =
+  QC.counterexample ("intersection: " ++ show (ab, inA, inB)) $ (inA && inB) === inAB
+  where
+    ab = intersectInterval a b
+    inA = withinInterval v a
+    inB = withinInterval v b
+    inAB = maybe False (withinInterval v) ab
+
+intersectCompleteLax :: VersionInterval -> VersionInterval -> Version -> QC.Property
+intersectCompleteLax a b v =
+  QC.counterexample ("intersection: " ++ show (ab, inA, inB)) $ (inA && inB) === inAB
+  where
+    ab = intersectInterval a b
+    inA = withinIntervalLax v a
+    inB = withinIntervalLax v b
+    inAB = maybe False (withinIntervalLax v) ab
+
+-------------------------------------------------------------------------------
+-- Stage 1
+-------------------------------------------------------------------------------
+
+stage1_valid :: VersionRange -> QC.Property
+stage1_valid vr = QC.counterexample ("stage1: " ++ show is) $ QC.property $ all validVersionInterval is
+  where
+    is = stage1 id vr
+
+stage1_complete :: VersionRange -> Version -> QC.Property
+stage1_complete vr v = QC.counterexample ("stage1: " ++ show is) $ withinRange v vr === any (withinInterval v) is
+  where
+    is = stage1 id vr
+
+stage1_complete_lax :: VersionRange -> Version -> QC.Property
+stage1_complete_lax vr v = QC.counterexample ("stage1: " ++ show is) $ withinRangeLax v vr === any (withinIntervalLax v) is
+  where
+    is = stage1 id vr
+
+-------------------------------------------------------------------------------
+-- Stage 2
+-------------------------------------------------------------------------------
+
+stage2_valid :: [VersionInterval] -> QC.Property
+stage2_valid is' = QC.counterexample ("stage2: " ++ show is) $ QC.property $ all validVersionInterval is
+  where
+    is = stage2 is'
+
+stage2_involutive :: [VersionInterval] -> QC.Property
+stage2_involutive is' = is1 === is2
+  where
+    is1 = stage2 is'
+    is2 = stage2 is1
+
+stage2_complete :: [VersionInterval] -> Version -> QC.Property
+stage2_complete is' v = QC.counterexample ("stage2: " ++ show is) $ any (withinInterval v) is' === any (withinInterval v) is
+  where
+    is = stage2 is'
+
+stage2_complete_lax :: [VersionInterval] -> Version -> QC.Property
+stage2_complete_lax is' v = QC.counterexample ("stage2: " ++ show is) $ any (withinIntervalLax v) is' === any (withinIntervalLax v) is
+  where
+    is = stage2 is'
+
+-------------------------------------------------------------------------------
+-- Stage 3
+-------------------------------------------------------------------------------
+
+stage3_valid :: [VersionInterval] -> QC.Property
+stage3_valid is' = QC.counterexample ("stage3: " ++ show is) $ QC.property $ all validVersionInterval is
+  where
+    is = stage3 (stage2 is')
+
+stage3_involutive :: [VersionInterval] -> QC.Property
+stage3_involutive is' = is1 === is2
+  where
+    is1 = stage3 (stage2 is')
+    is2 = stage3 is1
+
+stage3_complete :: [VersionInterval] -> Version -> QC.Property
+stage3_complete is' v = QC.counterexample ("stage3: " ++ show is) $ any (withinInterval v) is' === any (withinInterval v) is
+  where
+    is = stage3 (stage2 is')
+
+stage3_complete_lax :: [VersionInterval] -> Version -> QC.Property
+stage3_complete_lax is' v = QC.counterexample ("stage3: " ++ show is) $ any (withinIntervalLax v) is' === any (withinIntervalLax v) is
+  where
+    is = stage3 (stage2 is')
+
+-------------------------------------------------------------------------------
+-- Normalise
+-------------------------------------------------------------------------------
+
+normaliseInvolutive :: VersionRange -> QC.Property
+normaliseInvolutive vr = vr1 === vr2
+  where
+    vr1 = VersionInterval.normaliseVersionRange vr
+    vr2 = VersionInterval.normaliseVersionRange =<< vr1
+
+normaliseComplete :: VersionRange -> Version -> QC.Property
+normaliseComplete vr v = case VersionInterval.normaliseVersionRange vr of
+  Left _ -> QC.property True
+  Right vr' -> QC.counterexample ("normalised: " ++ show vr') $ withinRange v vr === withinRange v vr'
+
+normaliseCompleteLax :: VersionRange -> Version -> QC.Property
+normaliseCompleteLax vr v = case VersionInterval.normaliseVersionRange vr of
+  Left _ -> QC.property True
+  Right vr' -> QC.counterexample ("normalised: " ++ show vr') $ withinRangeLax v vr === withinRangeLax v vr'
+
+-------------------------------------------------------------------------------
+-- Predicates
+-------------------------------------------------------------------------------
+
+withinInterval :: Version -> VersionInterval -> Bool
+withinInterval v (VI l m u) = viGreater l && viLessM m && viLess u
+  where
+    viGreater (LB v') = v >= v'
+
+    viLessM NoMB = True
+    viLessM (MB v') = v < v'
+
+    viLess NoUB = True
+    viLess (UB v') = v < v'
+
+withinIntervalLax :: Version -> VersionInterval -> Bool
+withinIntervalLax v (VI l _ u) = viGreater l && viLess u
+  where
+    viGreater (LB v') = v >= v'
+
+    viLess NoUB = True
+    viLess (UB v') = v < v'
+
+withinRangeLax :: Version -> VersionRange -> Bool
+withinRangeLax v vr = withinRange v (transformCaretUpper vr)
+
+-------------------------------------------------------------------------------
+-- QC instances
+-------------------------------------------------------------------------------
+
+instance Arbitrary Version where
+  arbitrary =
+    QC.oneof
+      [ mkVersion <$> replicateM d vDigit
+        | d <- [1 .. 4]
+      ]
+    where
+      vDigit :: QC.Gen Int
+      vDigit = QC.elements [0 .. 9]
+
+  shrink v =
+    [ mkVersion v'
+      | v' <- shrink (versionNumbers v),
+        not (null v')
+    ]
+
+instance Arbitrary VersionRange where
+  arbitrary = QC.sized $ \n -> genVersionRange (intLog2 (max 1 n))
+
+  shrink vr = case projectVersionRange vr of
+    LaterVersionF v -> laterVersion <$> shrink v
+    OrLaterVersionF v -> orLaterVersion <$> shrink v
+    EarlierVersionF v -> earlierVersion <$> shrink v
+    OrEarlierVersionF v -> orEarlierVersion <$> shrink v
+    ThisVersionF v -> thisVersion <$> shrink v
+    MajorBoundVersionF v -> majorBoundVersion <$> shrink v
+    UnionVersionRangesF l r -> l : r : fmap (uncurry unionVersionRanges) (shrink (l, r))
+    IntersectVersionRangesF l r -> l : r : fmap (uncurry intersectVersionRanges) (shrink (l, r))
+
+genVersionRange :: Int -> QC.Gen VersionRange
+genVersionRange n
+  | n <= 1 =
+      QC.oneof
+        [ pure anyVersion,
+          thisVersion <$> arbitrary,
+          notThisVersion <$> arbitrary,
+          laterVersion <$> arbitrary,
+          earlierVersion <$> arbitrary,
+          orLaterVersion <$> arbitrary,
+          orEarlierVersion <$> arbitrary,
+          withinVersion <$> arbitrary,
+          majorBoundVersion <$> arbitrary
+        ]
+  | otherwise = do
+      l <- QC.chooseInt (1, n - 1)
+      let r = n - l
+      QC.oneof
+        [ unionVersionRanges <$> genVersionRange l <*> genVersionRange r,
+          intersectVersionRanges <$> genVersionRange l <*> genVersionRange r
+        ]
+
+instance Arbitrary VersionInterval where
+  arbitrary = QC.suchThat (VI <$> arbitrary <*> arbitrary <*> arbitrary) validVersionInterval
+
+  shrink (VI l m u) =
+    [ vi
+      | (l', m', u') <- shrink (l, m, u),
+        let vi = VI l' m' u',
+        validVersionInterval vi
+    ]
+
+instance Arbitrary LB where
+  arbitrary = LB <$> arbitrary
+  shrink (LB v) = LB <$> shrink v
+
+instance Arbitrary UB where
+  arbitrary =
+    QC.oneof
+      [ pure NoUB,
+        UB <$> arbitrary
+      ]
+
+  shrink NoUB = []
+  shrink (UB v) = NoUB : map UB (shrink v)
+
+instance Arbitrary MB where
+  arbitrary =
+    QC.oneof
+      [ pure NoMB,
+        MB <$> arbitrary
+      ]
+
+  shrink NoMB = []
+  shrink (MB v) = NoMB : map MB (shrink v)
diff --git a/source/test-suite/Main.hs b/source/test-suite/Main.hs
new file mode 100644
--- /dev/null
+++ b/source/test-suite/Main.hs
@@ -0,0 +1,12 @@
+import qualified CabalGild.Test.Golden
+import qualified CabalGild.Test.Interval
+import qualified Test.Tasty
+
+main :: IO ()
+main =
+  Test.Tasty.defaultMain $
+    Test.Tasty.testGroup
+      "cabal-gild"
+      [ CabalGild.Test.Golden.tests,
+        CabalGild.Test.Interval.tests
+      ]