re PR c++/28385 (templated function call goes awry)

        PR c++/28385
        * pt.c (tsubst) [TEMPLATE_TYPE_PARM]: Ignore quals from template
        if arg is a function.

From-SVN: r116203

gcc/cp/ChangeLog

+2006-08-16  Jason Merrill  <jason@redhat.com>
+
+	PR c++/28385
+	* pt.c (tsubst) [TEMPLATE_TYPE_PARM]: Ignore quals from template
+	if arg is a function.
+
 2006-08-16  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
 	PR c++/28593

gcc/cp/pt.c

@@ -7238,10 +7238,20 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 	  {
 	    if (TREE_CODE (t) == TEMPLATE_TYPE_PARM)
 	      {
+		int quals;
 		gcc_assert (TYPE_P (arg));
+
+		/* cv-quals from the template are discarded when
+		   substituting in a function or reference type.  */
+		if (TREE_CODE (arg) == FUNCTION_TYPE
+		    || TREE_CODE (arg) == METHOD_TYPE
+		    || TREE_CODE (arg) == REFERENCE_TYPE)
+		  quals = cp_type_quals (arg);
+		else
+		  quals = cp_type_quals (arg) | cp_type_quals (t);
+		  
 		return cp_build_qualified_type_real
-		  (arg, cp_type_quals (arg) | cp_type_quals (t),
-		   complain | tf_ignore_bad_quals);
+		  (arg, quals, complain | tf_ignore_bad_quals);
 	      }
 	    else if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM)
 	      {

gcc/testsuite/g++.dg/template/const1.C

+// PR c++/28385
+// instantiating op() with void()() was making the compiler think that 'fcn'
+// was const, so it could eliminate the call.
+
+// { dg-do run }
+
+extern "C" void abort (void);
+
+int barcnt = 0;
+
+class Foo {
+  public:
+    template<typename T>
+    void operator()(const T& fcn) {
+      fcn();
+    }
+};
+
+void bar() {
+  barcnt++;
+}
+
+int main() {
+  Foo myFoo;
+  myFoo(bar);
+  myFoo(&bar);
+  if (barcnt != 2)
+    abort ();
+  return 0;
+}