From patchwork Wed Oct 24 17:20:42 2012
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Subject: [C++] PR 34892
Date: Wed, 24 Oct 2012 07:20:42 -0000
From: Paolo Carlini <paolo.carlini@oracle.com>
X-Patchwork-Id: 193869
Message-Id: <5088236A.4060408@oracle.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: Jason Merrill <jason@redhat.com>

Hi,

a *very* old ICE on invalid, even a regression (from before variadic 
templates, I guess!). I tried various other tweaks, like catching the 
issue earlier but diagnostic quality decreases, too many cascading error 
messages. The below means I have to tweak only a couple of existing 
testcases, and I'm actually pretty happy with that, because we produce 
much less verbose diagnostic in both cases (1 error message less / 2 
respectively).

Tested x86_64-linux.

Thanks,
Paolo.

//////////////////////////
/cp
2012-10-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/34892
	* pt.c (coerce_template_parms): Check TREE_PURPOSE (parm)
	for error_mark_node.

/testsuite
2012-10-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/34892
	* g++.dg/template/crash114.C: New.
	* g++.dg/template/crash55.C: Tweak dg-error directive.
	* g++.dg/template/crash57.C: Likewise.


Index: cp/pt.c
===================================================================
--- cp/pt.c	(revision 192762)
+++ cp/pt.c	(working copy)
@@ -6645,11 +6645,12 @@ coerce_template_parms (tree parms,
       /* Get the Ith template parameter.  */
       parm = TREE_VEC_ELT (parms, parm_idx);
  
-      if (parm == error_mark_node)
-      {
-        TREE_VEC_ELT (new_inner_args, arg_idx) = error_mark_node;
-        continue;
-      }
+      if (parm == error_mark_node
+	  || TREE_PURPOSE (parm) == error_mark_node)
+	{
+	  TREE_VEC_ELT (new_inner_args, arg_idx) = error_mark_node;
+	  continue;
+	}
 
       /* Calculate the next argument.  */
       if (arg_idx < nargs)
Index: testsuite/g++.dg/template/crash114.C
===================================================================
--- testsuite/g++.dg/template/crash114.C	(revision 0)
+++ testsuite/g++.dg/template/crash114.C	(working copy)
@@ -0,0 +1,5 @@
+// PR c++/34892
+
+template<int=..., int=0> struct A {}; // { dg-error "expected" }
+// { dg-message "variadic" "" { target c++98 } 3 }
+A<0> a;                               // { dg-error "type" }
Index: testsuite/g++.dg/template/crash55.C
===================================================================
--- testsuite/g++.dg/template/crash55.C	(revision 192762)
+++ testsuite/g++.dg/template/crash55.C	(working copy)
@@ -3,4 +3,4 @@
 template<typename class T, T = T()> // { dg-error "nested-name-specifier|two or more|valid type" }
 struct A {};
 
-template<int> void foo(A<int>);     // { dg-error "mismatch|constant|template argument" }
+template<int> void foo(A<int>);     // { dg-error "type|template" }
Index: testsuite/g++.dg/template/crash57.C
===================================================================
--- testsuite/g++.dg/template/crash57.C	(revision 192762)
+++ testsuite/g++.dg/template/crash57.C	(working copy)
@@ -7,4 +7,4 @@ template<typename> struct B
     template<int(> struct C;    // { dg-error "token" }
 };
 
-A<char> a;                      // { dg-error "type/value mismatch|constant|declaration" }
+A<char> a;                      // { dg-error "type" }