Test for pattern type sigs in do-notation

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

@@ -46,3 +46,4 @@ test('read036', normal, compile, [''])
 test('read037', normal, compile, [''])
 test('read038', normal, compile, [''])
 test('read039', normal, compile, ['-fno-code'])
+test('read040', normal, compile, [''])

testsuite/tests/ghc-regress/parser/should_compile/read040.hs

+{-# OPTIONS -fglasgow-exts #-}
+
+-- A type signature on the LHS of a do-stmt was a parse
+-- error in 6.4.2, but ok thereafter
+
+module ShouldCompile where
+
+f () = do { x :: Bool <- return True 
+	  ; return x }