[m-rev.] diff: fix duplicate modes bug

[Simon Taylor]

Estimated hours taken: 1
Branches: main, release

Fix a bug reported by Michael Day.

compiler/post_typecheck.m:
	Don't attempt to remove duplicate procedures twice.

tests/invalid/duplicate_modes.{m,err_exp}:
	Test case.

Index: compiler/post_typecheck.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/post_typecheck.m,v
retrieving revision 1.42
diff -u -u -r1.42 post_typecheck.m
--- compiler/post_typecheck.m	14 Jan 2003 16:42:29 -0000	1.42
+++ compiler/post_typecheck.m	17 Jan 2003 03:40:32 -0000
@@ -999,18 +999,22 @@
 check_for_indistinguishable_modes(ModuleInfo, PredId, [ProcId | ProcIds],
 		PrevProcIds, PredInfo0, PredInfo) -->
 	check_for_indistinguishable_mode(ModuleInfo, PredId, ProcId,
-		PrevProcIds, PredInfo0, PredInfo1),
+		PrevProcIds, Removed, PredInfo0, PredInfo1),
+	{ PrevProcIds1 =
+		( if Removed = yes then PrevProcIds
+		  else [ProcId | PrevProcIds]
+		) },
 	check_for_indistinguishable_modes(ModuleInfo, PredId, ProcIds,
-		[ProcId | PrevProcIds], PredInfo1, PredInfo).
+		PrevProcIds1, PredInfo1, PredInfo).
 
 :- pred check_for_indistinguishable_mode(module_info, pred_id, proc_id,
-		list(proc_id), pred_info, pred_info, io__state, io__state).
+	list(proc_id), bool, pred_info, pred_info, io__state, io__state).
 :- mode check_for_indistinguishable_mode(in, in, in,
-		in, in, out, di, uo) is det.
+	in, out, in, out, di, uo) is det.
 
-check_for_indistinguishable_mode(_, _, _, [], PredInfo, PredInfo) --> [].
+check_for_indistinguishable_mode(_, _, _, [], no, PredInfo, PredInfo) --> [].
 check_for_indistinguishable_mode(ModuleInfo, PredId, ProcId1,
-		[ProcId | ProcIds], PredInfo0, PredInfo) -->
+		[ProcId | ProcIds], Removed, PredInfo0, PredInfo) -->
 	(
 		{ modes_are_indistinguishable(ProcId, ProcId1,
 			PredInfo0, ModuleInfo) }
@@ -1037,12 +1041,12 @@
 		;
 			[]
 		),
-		{ pred_info_remove_procid(PredInfo0, ProcId1, PredInfo1) }
+		{ pred_info_remove_procid(PredInfo0, ProcId1, PredInfo) },
+		{ Removed = yes }
 	;
-		{ PredInfo1 = PredInfo0 }
-	),
-	check_for_indistinguishable_mode(ModuleInfo, PredId, ProcId1,
-		ProcIds, PredInfo1, PredInfo).
+		check_for_indistinguishable_mode(ModuleInfo, PredId, ProcId1,
+			ProcIds, Removed, PredInfo0, PredInfo)
+	).
 
 %-----------------------------------------------------------------------------%
 
Index: tests/invalid/duplicate_modes.err_exp
===================================================================
RCS file: /home/mercury1/repository/tests/invalid/duplicate_modes.err_exp,v
retrieving revision 1.4
diff -u -u -r1.4 duplicate_modes.err_exp
--- tests/invalid/duplicate_modes.err_exp	31 Aug 1999 05:25:59 -0000	1.4
+++ tests/invalid/duplicate_modes.err_exp	17 Jan 2003 02:04:26 -0000
@@ -10,6 +10,12 @@
 duplicate_modes.m:008:   and `q((ground -> ground), (free -> ground)) is det'
 duplicate_modes.m:008:   are indistinguishable.
 duplicate_modes.m:009:   Here is the conflicting mode declaration.
+duplicate_modes.m:008: In mode declarations for predicate `duplicate_modes:q/2':
+duplicate_modes.m:008:   error: duplicate mode declaration.
+duplicate_modes.m:008:   Modes `q(in, out) is det'
+duplicate_modes.m:008:   and `q((ground -> ground), (free -> ground)) is det'
+duplicate_modes.m:008:   are indistinguishable.
+duplicate_modes.m:010:   Here is the conflicting mode declaration.
 duplicate_modes.m:014: In mode declarations for predicate `duplicate_modes:r/2':
 duplicate_modes.m:014:   error: duplicate mode declaration.
 duplicate_modes.m:014:   Modes `r(in, in) is semidet'
Index: tests/invalid/duplicate_modes.m
===================================================================
RCS file: /home/mercury1/repository/tests/invalid/duplicate_modes.m,v
retrieving revision 1.1
diff -u -u -r1.1 duplicate_modes.m
--- tests/invalid/duplicate_modes.m	23 Nov 1997 05:18:41 -0000	1.1
+++ tests/invalid/duplicate_modes.m	17 Jan 2003 02:03:12 -0000
@@ -7,7 +7,7 @@
 :- pred q(int, int).
 :- mode q(ground -> ground, free -> ground) is det.
 :- mode q(in, out) is det.
-
+:- mode q(in, out) is det.
 q(X, X).
 
 :- pred r(int, int).
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