Test Trac #3177

testsuite/tests/ghc-regress/th/T3177.hs

+{- LANGUAGE TemplateHaskell #-}
+
+-- Template Haskell type splices
+module T3177 where
+
+f :: $(id [t| Int |])
+f = 3
+
+class C a where
+  op :: a -> a
+
+instance C a => C ($([t| Maybe |]) a) where
+  op x = fmap op x
+

testsuite/tests/ghc-regress/th/T3177a.hs

+{- LANGUAGE TemplateHaskell #-}
+
+-- Template Haskell type splices
+-- Should fail, with a decent error message
+
+module T3177a where
+
+f :: $(id [t| Int Int |])
+f = 3
+
+g :: Int Int
+g = 3
+

testsuite/tests/ghc-regress/th/T3177a.stderr

+
+T3177a.hs:8:14:
+    `Int' is applied to too many type arguments
+    In the Template Haskell quotation [t| Int Int |]
+    In the first argument of `id', namely `[t| Int Int |]'
+    In the expression: id [t| Int Int |]
+
+T3177a.hs:11:5:
+    `Int' is applied to too many type arguments
+    In the type signature for `g':
+      g :: Int Int

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

@@ -142,4 +142,6 @@ test('TH_pragma',
      if_compiler_lt('ghc', '6.11', expect_fail),
      compile,
      ['-v0 -ddump-splices -dsuppress-uniques -S'])
+test('T3177', normal, compile, ['-v0'])
+test('T3177a', normal, compile_fail, ['-v0'])