C++ PATCH for c++/48594 (failure with overloaded ->* in template)

[Jason Merrill]

The code in build_offset_ref_from_tree was assuming that any ->* 
involved calling a bound pointer to member function.  But that's not 
necessarily the case: it could be calling a pointer to function or 
functor by way of a pointer to data member or overloaded ->* operator.

Tested x86_64-pc-linux-gnu, applying to trunk and 4.6.
commit f97457d26c50790378457509461df06d5e8dbbdc
Author: Jason Merrill <ja...@redhat.com>
Date:   Wed Apr 13 14:45:47 2011 -0400
        PR c++/48594
        * decl2.c (build_offset_ref_call_from_tree): Fix calling a functor
        or pointer to (non-member) function.

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 5b6f6ed..882bbf9 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -4081,10 +4081,13 @@ build_offset_ref_call_from_tree (tree fn, VEC(tree,gc) 
**args)
         parameter.  That must be done before the FN is transformed
         because we depend on the form of FN.  */
       make_args_non_dependent (*args);
-      object = build_non_dependent_expr (object);
-      if (TREE_CODE (fn) == DOTSTAR_EXPR)
-       object = cp_build_addr_expr (object, tf_warning_or_error);
-      VEC_safe_insert (tree, gc, *args, 0, object);
+      if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
+       {
+         object = build_non_dependent_expr (object);
+         if (TREE_CODE (fn) == DOTSTAR_EXPR)
+           object = cp_build_addr_expr (object, tf_warning_or_error);
+         VEC_safe_insert (tree, gc, *args, 0, object);
+       }
       /* Now that the arguments are done, transform FN.  */
       fn = build_non_dependent_expr (fn);
     }
@@ -4103,7 +4106,10 @@ build_offset_ref_call_from_tree (tree fn, VEC(tree,gc) 
**args)
       VEC_safe_insert (tree, gc, *args, 0, object_addr);
     }
 
-  expr = cp_build_function_call_vec (fn, args, tf_warning_or_error);
+  if (CLASS_TYPE_P (TREE_TYPE (fn)))
+    expr = build_op_call (fn, args, tf_warning_or_error);
+  else
+    expr = cp_build_function_call_vec (fn, args, tf_warning_or_error);
   if (processing_template_decl && expr != error_mark_node)
     expr = build_min_non_dep_call_vec (expr, orig_fn, orig_args);
 
diff --git a/gcc/testsuite/g++.dg/template/operator11.C 
b/gcc/testsuite/g++.dg/template/operator11.C
new file mode 100644
index 0000000..8d6b77a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/operator11.C
@@ -0,0 +1,25 @@
+// PR c++/48594
+// Test for uses of (X->*Y)() that don't actually involve a
+// pointer to member function.
+
+struct A { } a;
+struct B { } b;
+struct C * cp;
+
+struct Func { void operator()(); };
+Func operator->* (A, int);
+
+typedef void (*pfn)();
+pfn operator->* (B, int);
+
+pfn C::*cpfn;
+Func C::*cfunc;
+
+template <class T>
+void f()
+{
+  (a->*1)();
+  (b->*1)();
+  (cp->*cpfn)();
+  (cp->*cfunc)();
+}