Test/QuickCheck/All.hs: fix 'quickCheckAll' to read haskell sources i…

…n UTF-8

Today I've got an Agda build failure on a box running
LANG=C locale (UTF-8 incapable).

    examples/Heap.hs:151:10:
        Exception when trying to run compile-time code:
          examples/Heap.hs: hGetContents: invalid argument (invalid byte sequence)
          Code: quickCheckAll
        In the expression: $quickCheckAll
        In an equation for `main': main = $quickCheckAll

It's a common error of a 'readFile' assuming locale input.
Fixed to read in UTF-8 in recent GHCs.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

Test/QuickCheck/All.hs

@@ -22,6 +22,8 @@ import Data.Char
 import Data.List
 import Control.Monad
 
+import qualified System.IO as S
+
 -- | Test a polymorphic property, defaulting all type variables to 'Integer'.
 --
 -- Invoke as @$('polyQuickCheck' 'prop)@, where @prop@ is a property.
@@ -103,7 +105,7 @@ forAllProperties :: Q Exp -- :: (Property -> IO Result) -> IO Bool
 forAllProperties = do
   Loc { loc_filename = filename } <- location
   when (filename == "<interactive>") $ error "don't run this interactively"
-  ls <- runIO (fmap lines (readFile filename))
+  ls <- runIO (fmap lines (readUTF8File filename))
   let prefixes = map (takeWhile (\c -> isAlphaNum c || c == '_') . dropWhile (\c -> isSpace c || c == '>')) ls
       idents = nubBy (\x y -> snd x == snd y) (filter (("prop_" `isPrefixOf`) . snd) (zip [1..] prefixes))
       warning x = reportWarning ("Name " ++ x ++ " found in source file but was not in scope")
@@ -115,6 +117,19 @@ forAllProperties = do
          else return []
   [| runQuickCheckAll $(fmap (ListE . concat) (mapM quickCheckOne idents)) |]
 
+readUTF8File name = S.openFile name S.ReadMode >>=
+                    set_utf8_io_enc >>=
+                    S.hGetContents
+
+-- Deal with UTF-8 input and output.
+set_utf8_io_enc :: S.Handle -> IO S.Handle
+#if __GLASGOW_HASKELL__ > 611
+-- possibly if MIN_VERSION_base(4,2,0)
+set_utf8_io_enc h = do S.hSetEncoding h S.utf8; return h
+#else
+set_utf8_io_enc h = return h
+#endif
+
 -- | Test all properties in the current module.
 -- The name of the property must begin with @prop_@.
 -- Polymorphic properties will be defaulted to 'Integer'.

examples/Heap.hs

@@ -146,6 +146,8 @@ instance (Ord a, Arbitrary a) => Arbitrary (Heap a) where
 -- main
 
 return []
+-- quickCheckAll reads this file and treats it as UTF-8
+-- Here is a bait to test: Привет!
 main = $(quickCheckAll)
 
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