Add a layout test

testsuite/tests/ghc-regress/layout/Makefile

@@ -2,7 +2,7 @@ TOP=../../..
 include $(TOP)/mk/boilerplate.mk
 include $(TOP)/mk/test.mk
 
-layout001 layout002 layout003 layout004 layout005 layout006 layout007: %:
+layout001 layout002 layout003 layout004 layout005 layout006 layout007 layout008: %:
 	$(RM) $*.hi $*.o
 	echo Running with -XNoAlternativeLayoutRule
 	-"$(TEST_HC)" -v0 -XNoAlternativeLayoutRule -c $*.hs 2>&1

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

@@ -41,3 +41,9 @@ test('layout007',
      run_command,
      ['$MAKE -s --no-print-directory layout007'])
 
+test('layout008',
+     [extra_clean(['layout008.hi', 'layout008.o']),
+      only_compiler_types(['ghc'])],
+     run_command,
+     ['$MAKE -s --no-print-directory layout008'])
+

testsuite/tests/ghc-regress/layout/layout008.hs

+
+{-# LANGUAGE RecursiveDo, DoRec #-}
+{-# OPTIONS_GHC -fno-warn-deprecated-flags #-}
+
+module M where
+
+-- do, mdo and rec should all open layouts
+
+f :: IO ()
+f = do print 'a'
+       print 'b'
+
+g :: IO ()
+g = mdo print 'a'
+        print 'b'
+
+h :: IO ()
+h = do print 'a'
+       rec print 'b'
+           print 'c'
+       print 'd'
+

testsuite/tests/ghc-regress/layout/layout008.stdout

+Running with -XNoAlternativeLayoutRule
+Running with -XAlternativeLayoutRule