Test cases for #1900 & #1999

testsuite/tests/ghc-regress/gadt/T1999.hs

+{-# LANGUAGE FlexibleContexts, FlexibleInstances, GADTs #-}
+
+module Bug where
+
+class C a where
+  f :: G a -> ()
+
+instance (C ()) => C (b c) where
+  f (G x) = f x where
+
+data G a where
+  G  :: G () -> G (b c)

testsuite/tests/ghc-regress/gadt/all.T

@@ -87,3 +87,5 @@ test('gadt-escape1', if_compiler_lt('ghc', '6.9', skip), compile_fail, [''])
 
 test('Session', normal, compile_and_run, [''])
 test('CasePrune', normal, compile_and_run, [''])
+
+test('T1999', expect_fail, compile, [''])

testsuite/tests/ghc-regress/indexed-types/should_fail/T1900.hs

+{-# LANGUAGE TypeFamilies, FlexibleContexts #-}
+
+module Class4 where
+
+class (Eq (Depend s))=> Bug s where
+  type Depend s 
+  trans :: Depend s -> Depend s
+  
+instance Bug Int where
+  type Depend Int = ()
+  trans = (+1)
+  
+check :: (Bug s) => Depend s -> Bool
+check d = d == trans d
\ No newline at end of file

testsuite/tests/ghc-regress/indexed-types/should_fail/T1900.stderr

+
+T1900.hs:11:12:
+    No instance for (Num ())
+      arising from the literal `1' at T1900.hs:11:12
+    Possible fix: add an instance declaration for (Num ())
+    In the second argument of `(+)', namely `1'
+    In the expression: (+ 1)
+    In the definition of `trans': trans = (+ 1)
+
+T1900.hs:14:21:
+    Couldn't match expected type `Depend s'
+           against inferred type `Depend s1'
+    In the first argument of `trans', namely `d'
+    In the second argument of `(==)', namely `trans d'
+    In the expression: d == trans d

testsuite/tests/ghc-regress/indexed-types/should_fail/all.T

@@ -27,6 +27,7 @@ test('TyFamArity1', normal, compile_fail, [''])
 test('TyFamArity2', normal, compile_fail, [''])
 test('TyFamUndec', normal, compile_fail, [''])
 test('T2334', if_compiler_lt('ghc', '6.9', expect_fail), compile_fail, [''])
+test('T1900', if_compiler_lt('ghc', '6.9', expect_fail), compile_fail, [''])
 
 test('GADTwrong1', if_compiler_lt('ghc', '6.9', expect_fail), compile_fail, [''])