diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+### 0.4.3 [2018.06.16]
+* Fix a bug that caused debug-enabled GHC builds to panic when generating
+  code from this library (see
+  [Trac #15270](https://ghc.haskell.org/trac/ghc/ticket/15270)).
+  The fix only affects the library's internals, so no changes are user-facing.
+
 ### 0.4.2 [2018.05.14]
 * Backport the fixes for GHC Trac
   [#14364](https://ghc.haskell.org/trac/ghc/ticket/14364)
diff --git a/deriving-compat.cabal b/deriving-compat.cabal
--- a/deriving-compat.cabal
+++ b/deriving-compat.cabal
@@ -1,5 +1,5 @@
 name:                deriving-compat
-version:             0.4.2
+version:             0.4.3
 synopsis:            Backports of GHC deriving extensions
 description:         Provides Template Haskell functions that mimic deriving
                      extensions that were introduced or modified in recent versions
@@ -70,7 +70,7 @@
                    , GHC == 7.10.3
                    , GHC == 8.0.2
                    , GHC == 8.2.2
-                   , GHC == 8.4.2
+                   , GHC == 8.4.3
 cabal-version:       >=1.10
 
 source-repository head
diff --git a/src/Data/Deriving.hs b/src/Data/Deriving.hs
--- a/src/Data/Deriving.hs
+++ b/src/Data/Deriving.hs
@@ -99,6 +99,14 @@
       Instead, simply return the folded state (for `foldr`) or `mempty` (for
       `foldMap`), without inspecting the arguments.
 
+* In GHC 8.6, the @DerivingVia@ language extension was introduced.
+  @deriving-compat@ provides an interface which attempts to mimic this
+  extension (as well as @GeneralizedNewtypeDeriving@, which is a special case
+  of @DerivingVia@) as closely as possible.
+
+  Since the generated code requires the use of @TypeApplications@, this can
+  only be backported back to GHC 8.2.
+
 * In GHC 8.6, deriving `Read` was changed so as to factor out certain commonly
   used subexpressions, which significantly improve compliation times.
 -}
diff --git a/src/Data/Deriving/Internal.hs b/src/Data/Deriving/Internal.hs
--- a/src/Data/Deriving/Internal.hs
+++ b/src/Data/Deriving/Internal.hs
@@ -1587,19 +1587,19 @@
 boolTypeName = mkNameG_tc "ghc-prim" "GHC.Types" "Bool"
 
 falseDataName :: Name
-falseDataName = mkNameG_v "ghc-prim" "GHC.Types" "False"
+falseDataName = mkNameG_d "ghc-prim" "GHC.Types" "False"
 
 trueDataName :: Name
-trueDataName = mkNameG_v "ghc-prim" "GHC.Types" "True"
+trueDataName = mkNameG_d "ghc-prim" "GHC.Types" "True"
 #else
 boolTypeName :: Name
 boolTypeName = mkNameG_tc "ghc-prim" "GHC.Bool" "Bool"
 
 falseDataName :: Name
-falseDataName = mkNameG_v "ghc-prim" "GHC.Bool" "False"
+falseDataName = mkNameG_d "ghc-prim" "GHC.Bool" "False"
 
 trueDataName :: Name
-trueDataName = mkNameG_v "ghc-prim" "GHC.Bool" "True"
+trueDataName = mkNameG_d "ghc-prim" "GHC.Bool" "True"
 #endif
 
 #if MIN_VERSION_base(4,5,0)
diff --git a/src/Data/Deriving/Via.hs b/src/Data/Deriving/Via.hs
--- a/src/Data/Deriving/Via.hs
+++ b/src/Data/Deriving/Via.hs
@@ -9,7 +9,7 @@
 
 On @template-haskell-2.12@ or later (i.e., GHC 8.2 or later), this module
 exports functionality which emulates the @GeneralizedNewtypeDeriving@ and
-@DerivingVia@ GHC extensions.
+@DerivingVia@ GHC extensions (the latter of which was introduced in GHC 8.6).
 
 On older versions of @template-haskell@/GHC, this module does not export
 anything.
diff --git a/src/Data/Deriving/Via/Internal.hs b/src/Data/Deriving/Via/Internal.hs
--- a/src/Data/Deriving/Via/Internal.hs
+++ b/src/Data/Deriving/Via/Internal.hs
@@ -9,7 +9,7 @@
 
 On @template-haskell-2.12@ or later (i.e., GHC 8.2 or later), this module
 exports functionality which emulates the @GeneralizedNewtypeDeriving@ and
-@DerivingVia@ GHC extensions.
+@DerivingVia@ GHC extensions (the latter of which was introduced in GHC 8.6).
 
 On older versions of @template-haskell@/GHC, this module does not export
 anything.