[project @ 2003-02-06 09:30:14 by simonpj]

Add error-message test

testsuite/tests/ghc-regress/deriving/should_fail/all.T

@@ -6,3 +6,4 @@ test('drvfail004', normal, compile_fail, [''])
 test('drvfail005', normal, compile_fail, [''])
 test('drvfail006', normal, compile_fail, [''])
 test('drvfail007', normal, compile_fail, [''])
+test('drvfail008', normal, compile_fail, [''])

testsuite/tests/ghc-regress/deriving/should_fail/drvfail008.hs

+-- Should fail without -fglasgow-exts
+-- Succeeds with -fglasgow-exts
+
+module ShouldFail where
+
+import Control.Monad.State
+
+data S = S Int
+
+newtype M a = M (StateT S IO a) deriving( Monad )
+
+
+
+

testsuite/tests/ghc-regress/deriving/should_fail/drvfail008.stderr

+
+drvfail008.hs:10:
+    Can't make a derived instance of `Monad M'
+    (`Monad' is not a derivable class
+     Try -fglasgow-exts for GHC's newtype-deriving extension)
+    When deriving instances for type `M'