Test Trac #6152

testsuite/tests/indexed-types/should_compile/Makefile

@@ -18,3 +18,10 @@ T5955:
 	$(RM) T5955.o T5955.hi T5955a.o T5955a.hi 
 	'$(TEST_HC)' $(TEST_HC_OPTS) -c T5955a.hs
 	'$(TEST_HC)' $(TEST_HC_OPTS) -c T5955.hs
+
+
+# Compiling twice made 7.4.1 break
+T6152:
+	$(RM) T6152.o T6152.hi 
+	'$(TEST_HC)' $(TEST_HC_OPTS) -c T6152.hs
+	'$(TEST_HC)' $(TEST_HC_OPTS) -c T6152.hs -fforce-recomp

testsuite/tests/indexed-types/should_compile/T6152.hs

+{-# LANGUAGE DataKinds, TypeFamilies, GADTs #-}
+
+module T6152 where
+
+data U = Unit
+
+data SU (a :: U) where
+   SInt :: SU Unit
+
+type family I (a :: U) :: U
+type instance I Unit = Unit
+
+type SUI a = SU (I a)
+

testsuite/tests/indexed-types/should_compile/all.T

@@ -189,4 +189,9 @@ test('T5955',
      run_command,
      ['$MAKE -s --no-print-directory T5955'])
 
+test('T6152',
+     normal,
+     run_command,
+     ['$MAKE -s --no-print-directory T6152'])
+
 test('T6088', normal, compile, [''])