Patchwork C++ PATCH for c++/51973 (rejects-valid with explicit template args in call in function signature)

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Submitter Jason Merrill
Date Jan. 24, 2012, 5:16 p.m.
Message ID <4F1EE750.2090505@redhat.com>
Download mbox | patch
Permalink /patch/137597/
State New
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Comments

Jason Merrill - Jan. 24, 2012, 5:16 p.m.
When we compare dependent names, we need to compare any explicit 
template args as well.

Tested x86_64-pc-linux-gnu, applying to trunk.

Patch

commit 7446bd5c430bab0ea5b496b93d92d298bb023572
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Jan 24 10:42:22 2012 -0500

    	PR c++/51973
    	* tree.c (called_fns_equal): Check template args.
    	(cp_tree_equal): Call it.

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index cf39800..b80b52a 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2174,6 +2174,33 @@  decl_anon_ns_mem_p (const_tree decl)
     }
 }
 
+/* Subroutine of cp_tree_equal: t1 and t2 are the CALL_EXPR_FNs of two
+   CALL_EXPRS.  Return whether they are equivalent.  */
+
+static bool
+called_fns_equal (tree t1, tree t2)
+{
+  /* Core 1321: dependent names are equivalent even if the overload sets
+     are different.  But do compare explicit template arguments.  */
+  tree name1 = dependent_name (t1);
+  tree name2 = dependent_name (t2);
+  if (name1 || name2)
+    {
+      tree targs1 = NULL_TREE, targs2 = NULL_TREE;
+
+      if (name1 != name2)
+	return false;
+
+      if (TREE_CODE (t1) == TEMPLATE_ID_EXPR)
+	targs1 = TREE_OPERAND (t1, 1);
+      if (TREE_CODE (t2) == TEMPLATE_ID_EXPR)
+	targs2 = TREE_OPERAND (t2, 1);
+      return cp_tree_equal (targs1, targs2);
+    }
+  else
+    return cp_tree_equal (t1, t2);
+}
+
 /* Return truthvalue of whether T1 is the same tree structure as T2.
    Return 1 if they are the same. Return 0 if they are different.  */
 
@@ -2261,12 +2288,7 @@  cp_tree_equal (tree t1, tree t2)
       {
 	tree arg1, arg2;
 	call_expr_arg_iterator iter1, iter2;
-	/* Core 1321: dependent names are equivalent even if the
-	   overload sets are different.  */
-	tree name1 = dependent_name (CALL_EXPR_FN (t1));
-	tree name2 = dependent_name (CALL_EXPR_FN (t2));
-	if (!(name1 && name2 && name1 == name2)
-	    && !cp_tree_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
+	if (!called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
 	  return false;
 	for (arg1 = first_call_expr_arg (t1, &iter1),
 	       arg2 = first_call_expr_arg (t2, &iter2);
@@ -2354,26 +2376,18 @@  cp_tree_equal (tree t1, tree t2)
 			      TREE_TYPE (TEMPLATE_PARM_DECL (t2))));
 
     case TEMPLATE_ID_EXPR:
+      return (cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0))
+	      && cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1)));
+
+    case TREE_VEC:
       {
 	unsigned ix;
-	tree vec1, vec2;
-
-	if (!cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)))
+	if (TREE_VEC_LENGTH (t1) != TREE_VEC_LENGTH (t2))
 	  return false;
-	vec1 = TREE_OPERAND (t1, 1);
-	vec2 = TREE_OPERAND (t2, 1);
-
-	if (!vec1 || !vec2)
-	  return !vec1 && !vec2;
-
-	if (TREE_VEC_LENGTH (vec1) != TREE_VEC_LENGTH (vec2))
-	  return false;
-
-	for (ix = TREE_VEC_LENGTH (vec1); ix--;)
-	  if (!cp_tree_equal (TREE_VEC_ELT (vec1, ix),
-			      TREE_VEC_ELT (vec2, ix)))
+	for (ix = TREE_VEC_LENGTH (t1); ix--;)
+	  if (!cp_tree_equal (TREE_VEC_ELT (t1, ix),
+			      TREE_VEC_ELT (t2, ix)))
 	    return false;
-
 	return true;
       }
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/sfinae31.C b/gcc/testsuite/g++.dg/cpp0x/sfinae31.C
new file mode 100644
index 0000000..ea151fe
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/sfinae31.C
@@ -0,0 +1,13 @@ 
+// PR c++/51973
+// { dg-options -std=c++0x }
+
+template <class T>
+void f(T t) { };
+
+template <class T> decltype(f<T>(0)) g();
+template <class T> decltype(f<T*>(0)) g();
+
+int main()
+{
+  g<void>();
+}