re PR c++/51403 (ICE with invalid template parameter)

	PR c++/51403
	* pt.c (unify): Handle error_mark_node.

From-SVN: r183132

gcc/cp/ChangeLog

+2012-01-12  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51403
+	* pt.c (unify): Handle error_mark_node.
+
 2012-01-11  Jason Merrill  <jason@redhat.com>
 
 	PR c++/51565

gcc/cp/pt.c

@@ -16272,6 +16272,8 @@ unify (tree tparms, tree targs, tree parm, tree arg, int strict,
       idx = TEMPLATE_TYPE_IDX (parm);
       targ = TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx);
       tparm = TREE_VALUE (TREE_VEC_ELT (tparms, idx));
+      if (tparm == error_mark_node)
+	return unify_invalid (explain_p);
 
       /* Check for mixed types and values.  */
       if ((TREE_CODE (parm) == TEMPLATE_TYPE_PARM

gcc/testsuite/ChangeLog

+2012-01-12  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51403
+	* g++.dg/template/arg8.C: New.
+
 2012-01-12  Ira Rosen  <irar@il.ibm.com>
 
 	PR tree-optimization/51799

gcc/testsuite/g++.dg/template/arg8.C

+template<typename T, void, typename U> // { dg-error "void" }
+void foo(T, U, int) {}
+
+void bar()
+{
+  foo(0, 0, 0);			// { dg-error "no match" }
+}