Add tests for -XMultiParamTypeClasses

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

@@ -58,3 +58,5 @@ test('read048', normal, compile, [''])
 test('read049', normal, compile, [''])
 test('read050', normal, compile, [''])
 test('read051', normal, compile, [''])
+test('read052', normal, compile, [''])
+test('read053', normal, compile, [''])

testsuite/tests/ghc-regress/parser/should_compile/read052.hs

+
+{-# OPTIONS_GHC -XMultiParamTypeClasses #-}
+
+module Foo where
+
+class Foo a b
+

testsuite/tests/ghc-regress/parser/should_compile/read053.hs

+
+{-# LANGUAGE MultiParamTypeClasses #-}
+
+module Foo where
+
+class Foo a b
+

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

@@ -43,3 +43,4 @@ test('read033', normal, compile_fail, [''])
 test('read034', normal, compile_fail, [''])
 test('read035', normal, compile_fail, [''])
 test('read036', normal, compile_fail, [''])
+test('read037', normal, compile_fail, [''])

testsuite/tests/ghc-regress/parser/should_fail/read037.hs

+
+module Foo where
+
+class Foo a b
+

testsuite/tests/ghc-regress/parser/should_fail/read037.stderr

+
+read037.hs:4:0:
+    Too many parameters for class `Foo'
+    (Use -XMultiParamTypeClasses to allow multi-parameter classes)
+    In the class declaration for `Foo'