re PR c++/71169 (ICE on invalid C++ code in pop_nested_class (cp/class.c:7785))

/cp
2018-03-09  Jason Merrill  <jason@redhat.com>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/71169
	PR c++/71832
	* pt.c (any_erroneous_template_args_p): New.
	* cp-tree.h (any_erroneous_template_args_p): Declare it.
	* parser.c (cp_parser_class_specifier_1): Use it.

/testsuite
2018-03-09  Jason Merrill  <jason@redhat.com>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/71169
	PR c++/71832
	* g++.dg/cpp0x/pr71169.C: New.
	* g++.dg/cpp0x/pr71169-2.C: Likewise.
	* g++.dg/cpp0x/pr71832.C: Likewise.

Co-Authored-By: Paolo Carlini <paolo.carlini@oracle.com>

From-SVN: r258401

gcc/cp/ChangeLog

+2018-03-10  Jason Merrill  <jason@redhat.com>
+	    Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/71169
+	PR c++/71832
+	* pt.c (any_erroneous_template_args_p): New.
+	* cp-tree.h (any_erroneous_template_args_p): Declare it.
+	* parser.c (cp_parser_class_specifier_1): Use it.
+
 2018-03-09  Jason Merrill  <jason@redhat.com>
 
 	PR c++/84726 - unnecessary capture of constant vars.

gcc/cp/cp-tree.h

@@ -6569,6 +6569,7 @@ extern int processing_template_parmlist;
 extern bool dependent_type_p			(tree);
 extern bool dependent_scope_p			(tree);
 extern bool any_dependent_template_arguments_p  (const_tree);
+extern bool any_erroneous_template_args_p       (const_tree);
 extern bool dependent_template_p		(tree);
 extern bool dependent_template_id_p		(tree, tree);
 extern bool type_dependent_expression_p		(tree);

gcc/cp/parser.c

@@ -22669,6 +22669,16 @@ cp_parser_class_specifier_1 (cp_parser* parser)
       cp_default_arg_entry *e;
       tree save_ccp, save_ccr;
 
+      if (any_erroneous_template_args_p (type))
+	{
+	  /* Skip default arguments, NSDMIs, etc, in order to improve
+	     error recovery (c++/71169, c++/71832).  */
+	  vec_safe_truncate (unparsed_funs_with_default_args, 0);
+	  vec_safe_truncate (unparsed_nsdmis, 0);
+	  vec_safe_truncate (unparsed_classes, 0);
+	  vec_safe_truncate (unparsed_funs_with_definitions, 0);
+	}
+
       /* In a first pass, parse default arguments to the functions.
 	 Then, in a second pass, parse the bodies of the functions.
 	 This two-phased approach handles cases like:

gcc/cp/pt.c

@@ -25048,6 +25048,39 @@ any_dependent_template_arguments_p (const_tree args)
   return false;
 }
 
+/* Returns true if ARGS contains any errors.  */
+
+bool
+any_erroneous_template_args_p (const_tree args)
+{
+  int i;
+  int j;
+
+  if (args == error_mark_node)
+    return true;
+
+  if (args && TREE_CODE (args) != TREE_VEC)
+    {
+      if (tree ti = get_template_info (args))
+	args = TI_ARGS (ti);
+      else
+	args = NULL_TREE;
+    }
+
+  if (!args)
+    return false;
+
+  for (i = 0; i < TMPL_ARGS_DEPTH (args); ++i)
+    {
+      const_tree level = TMPL_ARGS_LEVEL (args, i + 1);
+      for (j = 0; j < TREE_VEC_LENGTH (level); ++j)
+	if (error_operand_p (TREE_VEC_ELT (level, j)))
+	  return true;
+    }
+
+  return false;
+}
+
 /* Returns TRUE if the template TMPL is type-dependent.  */
 
 bool

gcc/testsuite/ChangeLog

+2018-03-09  Jason Merrill  <jason@redhat.com>
+	    Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/71169
+	PR c++/71832
+	* g++.dg/cpp0x/pr71169.C: New.
+	* g++.dg/cpp0x/pr71169-2.C: Likewise.
+	* g++.dg/cpp0x/pr71832.C: Likewise.
+
 2018-03-09  Peter Bergner  <bergner@vnet.ibm.com>
 
 	PR target/83969

gcc/testsuite/g++.dg/cpp0x/pr71169-2.C

+// { dg-do compile { target c++11 } }
+
+template <Preconditioner> class A {  // { dg-error "declared" }
+  template <class = int> void m_fn1() {
+    m_fn1();
+    }
+};
+
+template<typename>
+struct B
+{
+  int f(int = 0) { return 0; }
+};
+
+int main()
+{
+  B<int> b;
+  return b.f();
+}

gcc/testsuite/g++.dg/cpp0x/pr71169.C

+// { dg-do compile { target c++11 } }
+
+template <Preconditioner> class A {  // { dg-error "declared" }
+  template <class = int> void m_fn1() {
+    m_fn1();
+    }
+};

gcc/testsuite/g++.dg/cpp0x/pr71832.C

+// { dg-do compile { target c++11 } }
+
+template < typename decltype (0) > struct A  // { dg-error "expected|two or more" }
+{ 
+  void foo () { baz (); }
+  template < typename ... S > void baz () {}
+};