Tests for Trac #1154

testsuite/tests/ghc-regress/typecheck/should_compile/all.T

@@ -237,6 +237,7 @@ test('tc221', normal, compile, [''])
 test('tc222', normal, compile, [''])
 test('tc223', normal, compile, [''])
 test('tc224', normal, compile, [''])
+test('tc225', normal, compile, [''])
 
 test('faxen', normal, compile, [''])
 

testsuite/tests/ghc-regress/typecheck/should_compile/tc225.hs

+{-# OPTIONS -fglasgow-exts #-}
+
+-- Newtype in GADT syntax
+
+module ShouldCompile where
+
+newtype Bug a where Bug :: a -> Bug a

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

@@ -161,3 +161,4 @@ test('tcfail172', normal, compile_fail, [''])
 test('tcfail173', normal, compile_fail, [''])
 test('tcfail174', normal, compile_fail, [''])
 test('tcfail175', normal, compile_fail, [''])
+test('tcfail176', normal, compile_fail, [''])

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail176.hs

+{-# OPTIONS -fglasgow-exts #-}
+
+-- Newtype in GADT syntax
+
+module ShouldFail where
+
+newtype Bug a where Bug :: a -> Maybe a

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail176.stderr

+
+tcfail176.hs:7:20:
+    Data constructor `Bug' returns type `Maybe'
+      instead of its parent type
+    In the definition of data constructor `Bug'
+    In the newtype declaration for `Bug'