diff: fix bug for ambiguous qualified func

[Fergus Henderson]

Estimated hours taken: 0.75

compiler/modecheck_unify.m:
	Fix a bug which caused the compiler to generate incorrect
	code for the case where a function had the same name and arity
	as a data constructor (but a different return type),
	and the data constructor was used with an explicit module
	qualifier -- it incorrectly ignored the types and chose
	the function rather than the data constructor.

tests/hard_coded/Mmakefile:
tests/hard_coded/func_ctor_ambig.m:
tests/hard_coded/func_ctor_ambig.exp:
	Regression test.

cvs diff  compiler/modecheck_unify.m tests/hard_coded/Mmakefile tests/hard_coded/func_ctor_ambig.exp tests/hard_coded/func_ctor_ambig.m
Index: compiler/modecheck_unify.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/modecheck_unify.m,v
retrieving revision 1.31
diff -u -r1.31 modecheck_unify.m
--- modecheck_unify.m	1998/02/15 21:12:09	1.31
+++ modecheck_unify.m	1998/02/19 03:02:34
@@ -169,27 +169,19 @@
 		%
 
 		\+ code_util__compiler_generated(PredInfo),
-		(
-			PredName = unqualified(UnqualPName),
-			predicate_table_search_func_name_arity(PredTable,
-				UnqualPName, Arity, PredIds),
-  
-			% Check if there any of the candidate functions,
-			% have argument/return types which subsume the actual
-			% argument/return types of this function call
-  
-			pred_info_typevarset(PredInfo, TVarSet),
-			map__apply_to_list(ArgVars0, VarTypes0, ArgTypes0),
-			list__append(ArgTypes0, [TypeOfX], ArgTypes),
-			typecheck__find_matching_pred_id(PredIds, ModuleInfo0,
-				TVarSet, ArgTypes, PredId, QualifiedFuncName)
 
-		;
-			PredName = qualified(FuncModule, UnqualName),
-			predicate_table_search_func_m_n_a(PredTable,
-				    FuncModule, UnqualName, Arity, [PredId]),
-			QualifiedFuncName = PredName
-		)
+		predicate_table_search_func_sym_arity(PredTable,
+			PredName, Arity, PredIds),
+
+		% Check if any of the candidate functions have
+		% argument/return types which subsume the actual
+		% argument/return types of this function call
+
+		pred_info_typevarset(PredInfo, TVarSet),
+		map__apply_to_list(ArgVars0, VarTypes0, ArgTypes0),
+		list__append(ArgTypes0, [TypeOfX], ArgTypes),
+		typecheck__find_matching_pred_id(PredIds, ModuleInfo0,
+			TVarSet, ArgTypes, PredId, QualifiedFuncName)
 	->
 		%
 		% Convert function calls into predicate calls:
Index: tests/hard_coded/Mmakefile
===================================================================
RCS file: /home/mercury1/repository/tests/hard_coded/Mmakefile,v
retrieving revision 1.16
diff -u -r1.16 Mmakefile
--- Mmakefile	1998/02/05 02:51:15	1.16
+++ Mmakefile	1998/02/19 03:13:27
@@ -31,6 +31,7 @@
 	float_rounding_bug \
 	free_free_mode \
 	func_and_pred \
+	func_ctor_ambig \
 	func_test \
 	getopt_test \
 	ground_dd \
Index: tests/hard_coded/func_ctor_ambig.exp
===================================================================
RCS file: func_ctor_ambig.exp
diff -N func_ctor_ambig.exp
--- /dev/null	Thu Feb 19 14:14:17 1998
+++ func_ctor_ambig.exp	Thu Feb 19 14:13:03 1998
@@ -0,0 +1,4 @@
+bar = 42
+bar2 = 42
+baz = ambig
+baz2 = ambig
Index: tests/hard_coded/func_ctor_ambig.m
===================================================================
RCS file: func_ctor_ambig.m
diff -N func_ctor_ambig.m
--- /dev/null	Thu Feb 19 14:14:17 1998
+++ func_ctor_ambig.m	Thu Feb 19 14:14:52 1998
@@ -0,0 +1,35 @@
+% Mercury 0.7.3 generated incorrect code for this test case.
+
+:- module func_ctor_ambig.
+:- interface.
+:- import_module io.
+
+:- type t.
+:- func bar = int.
+:- func baz = t.
+:- func bar2 = int.
+:- func baz2 = t.
+
+:- pred main(io__state::di, io__state::uo) is det.
+
+:- implementation.
+
+main -->
+	print("bar = "), print(bar), nl,
+	print("bar2 = "), print(bar2), nl,
+	print("baz = "), print(baz), nl,
+	print("baz2 = "), print(baz2), nl.
+
+:- type t ---> ambig.
+
+:- func ambig = int.
+ambig = 42.
+
+bar = ambig.
+
+baz = ambig.
+
+bar2 = func_ctor_ambig:ambig.
+
+baz2 = func_ctor_ambig:ambig.
+

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3         |     -- the last words of T. S. Garp.