diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Revision history for error
 
+## 0.1.1.0 -- 2021-10-28
+
+* Add `HasCallStack` to `expectError` and `unwrapError`.
+* Add `showToError` and `exceptionToError`.
+* Improved documentation of existing functions.
+
 ## 0.1.0.0 -- 2021-06-26
 
 * Initial version. More or less feature complete, 
diff --git a/error.cabal b/error.cabal
--- a/error.cabal
+++ b/error.cabal
@@ -1,6 +1,6 @@
 cabal-version:      2.4
 name:               error
-version:            0.1.0.0
+version:            0.1.1.0
 
 synopsis: The canonical error type
 
@@ -38,6 +38,16 @@
 
     -- LANGUAGE extensions used by modules in this package.
     -- other-extensions:
+
+test-suite doctest
+    type:             exitcode-stdio-1.0
+    hs-source-dirs:   test
+    main-is:          DocTest.hs
+    default-language: Haskell2010
+    build-depends:
+        base
+      , doctest
+
 
 source-repository head
   type: git
diff --git a/src/Data/Error.hs b/src/Data/Error.hs
--- a/src/Data/Error.hs
+++ b/src/Data/Error.hs
@@ -1,17 +1,39 @@
 {-# LANGUAGE OverloadedStrings #-}
 module Data.Error
   ( Error,
+    -- * Error creation
     newError,
+    -- *** From 'Show' and 'Exception'
+
+    -- | These two functions can be helpful, but consider that they don’t always provide very user-friendly error messages.
+    -- It is recommended that you use `addContext` to improve the messages generated by 'showToError' and 'exceptionToError'.
+    showToError,
+    exceptionToError,
+    -- * Adding context
     addContext,
+    -- * Pretty printing
     prettyError,
-    unwrapError,
+    -- * Unsafe unwrapping
+
+    -- | Sometimes you want to assure that an 'Error' could not have happened at runtime,
+    -- even though there is the possibility in the types.
+    -- In that case you can use 'expectError'/'unwrapError'.
+    -- They will panic at runtime if there was an error.
+    --
+    -- 'expectError' should usually be preffered, since it adds a context message.
+    --
+    -- These are modelled after @<https://doc.rust-lang.org/std/result/enum.Result.html#method.expect Result::expect()>@
+    -- and @<https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap Result::unwrap()>@ in the rust stdlib.
     expectError,
+    unwrapError,
   )
 where
 
 import Data.Function ((&))
 import Data.Text (Text)
 import qualified Data.Text as Text
+import GHC.Stack (HasCallStack)
+import Control.Exception (Exception (displayException))
 
 -- | The canonical @Error@ type.
 --
@@ -26,6 +48,23 @@
 newError :: Text -> Error
 newError msg = Error [msg]
 
+-- | Create an error from a `Show` type.
+--
+-- If your type implements 'Exception', it is usually better to use 'exceptionToError' instead.
+-- Strings produced by 'show' are usually not very user-friendly.
+--
+-- Note: goes via `String`, so not efficient.
+showToError :: Show a => a -> Error
+showToError = newError . Text.pack . show
+
+-- | Create an error from an 'Exception' type.
+--
+-- The default implementation of 'displayException' is 'show', so the same user-friendliness problems of 'showToError' apply.
+--
+-- Note: goes via `String`, so not efficient.
+exceptionToError :: Exception exc => exc -> Error
+exceptionToError = newError . Text.pack . displayException
+
 -- | Add a higher-level context to an 'Error'.
 --
 -- For example, your code hits a “file not found” I/O exception.
@@ -53,17 +92,15 @@
 --
 -- Example:
 --
--- @
--- prettyError $ newError "file not found: ./foo"
---
--- ==> "file not found: ./foo"
---
--- prettyError
---   $ addContext "Trying to open config file"
---     $ newError "file not found: ./foo"
+-- >>> prettyError $ newError "file not found: ./foo"
+-- "file not found: ./foo"
 --
--- ==> "Trying to open config file: file not found: ./foo"
--- @
+-- >>> :{
+--   prettyError
+--     $ addContext "Trying to open config file"
+--       $ newError "file not found: ./foo"
+-- :}
+-- "Trying to open config file: file not found: ./foo"
 prettyError :: Error -> Text
 prettyError (Error es) = Text.intercalate ": " es
 
@@ -71,20 +108,17 @@
 --
 -- Abort with the 'Error's message if it was a 'Left'.
 --
--- Panic: if Error
+-- __Panics__: if Error
 --
 -- Example:
 --
--- @
--- unwrapError $ Left (newError "oh no!")
---
--- ==> *** Exception: oh no!
---
--- unwrapError $ Right 42
+-- >>> unwrapError $ Left (newError "oh no!")
+-- *** Exception: oh no!
+-- ...
 --
--- ==> 42
--- @
-unwrapError :: Either Error p -> p
+-- >>> unwrapError $ Right 42
+-- 42
+unwrapError :: HasCallStack => Either Error p -> p
 unwrapError e = case e of
   Left err -> error (prettyError err & Text.unpack)
   Right a -> a
@@ -95,20 +129,17 @@
 --
 -- The text message is added to the 'Error' as additional context before aborting.
 --
--- Panic: if Error
+-- __Panics__: if Error
 --
 -- Example:
 --
--- @
--- exceptError "something bad happened" $ Left (newError "oh no!")
---
--- ==> *** Exception: something bad happened: oh no!
---
--- exceptError $ Right 42
+-- >>> expectError "something bad happened" $ Left (newError "oh no!")
+-- *** Exception: something bad happened: oh no!
+-- ...
 --
--- ==> 42
--- @
-expectError :: Text -> Either Error p -> p
+-- >>> expectError "something bad happened" $ Right 42
+-- 42
+expectError :: HasCallStack => Text -> Either Error p -> p
 expectError context e = case e of
   Left err ->
     error
diff --git a/test/DocTest.hs b/test/DocTest.hs
new file mode 100644
--- /dev/null
+++ b/test/DocTest.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import Test.DocTest
+
+main :: IO ()
+main = doctest [ "-XOverloadedStrings", "src" ]