Add test for Trac #2024

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

+{-# LANGUAGE TemplateHaskell, ScopedTypeVariables #-}
+module Foo where
+
+
+$([d| f :: forall a. a->a
+      f x = x::a 
+    |])

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

+
+TH_scopedTvs.hs:6:12:
+    Illegal lexically-scoped type variable `a'
+    Lexically scoped type variables are not supported by Template Haskell

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

@@ -77,6 +77,8 @@ test('TH_dataD1', normal, compile_fail, ['-v0'])
 test('TH_ppr1', normal, compile_and_run, ['-fglasgow-exts'])
 
 test('TH_fail', normal, compile_fail, ['-v0'])
+test('TH_scopedTvs', normal, compile_fail, ['-v0'])
+
 test('TH_runIO', if_compiler_lt('ghc','6.9', namebase('TH_runIO-6.8')), compile_fail, ['-v0'])
 
 test('TH_ghci1', normal, ghci_script, ['TH_ghci1.script'])