Add tests for -XParallelListComp

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

@@ -60,3 +60,5 @@ test('read050', normal, compile, [''])
 test('read051', normal, compile, [''])
 test('read052', normal, compile, [''])
 test('read053', normal, compile, [''])
+test('read054', normal, compile, [''])
+test('read055', normal, compile, [''])

testsuite/tests/ghc-regress/parser/should_compile/read054.hs

+
+{-# OPTIONS_GHC -XParallelListComp #-}
+
+module Foo where
+
+foo = [ ()
+      | () <- foo
+      | () <- foo
+      ]
+

testsuite/tests/ghc-regress/parser/should_compile/read055.hs

+
+{-# LANGUAGE ParallelListComp #-}
+
+module Foo where
+
+foo = [ ()
+      | () <- foo
+      | () <- foo
+      ]
+

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

@@ -44,3 +44,4 @@ test('read034', normal, compile_fail, [''])
 test('read035', normal, compile_fail, [''])
 test('read036', normal, compile_fail, [''])
 test('read037', normal, compile_fail, [''])
+test('read038', normal, compile_fail, [''])

testsuite/tests/ghc-regress/parser/should_fail/read038.hs

+
+module Foo where
+
+foo = [ ()
+      | () <- foo
+      | () <- foo
+      ]
+

testsuite/tests/ghc-regress/parser/should_fail/read038.stderr

+
+read038.hs:4:6:
+    Illegal parallel list comprehension: use -XParallelListComp