[C++ Patch] PR 78637 ("ICE on invalid C++ code (internal compiler error: in pop_namespace, at cp/name-lookup.c:3826)")

[Paolo Carlini]

Hi,

this regression is caused by my fix for c++/60385, where I changed 
push_namespace to early return (a bool) when pushdecl fails. In the 
present testcase, a different push_namespace call in 
cp_parser_namespace_definition, for nested namespace definitions, fails, 
thus returns early, and that is inconsistent with the final loop 
(pop_namespace ICEs):

  /* Finish the nested namespace definitions.  */
  while (nested_definition_count--)
    pop_namespace ();

To fix this problem, I think we can simply increment 
nested_definition_count only when push_namespace succeeds. Tested 
x86_64-linux.

Thanks, Paolo.

//////////////////////

/cp
2016-12-02  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/78637
        * parser.c (cp_parser_namespace_definition): Increment
        nested_definition_count only if push_namespace succeeds.

/testsuite
2016-12-02  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/78637
        * g++.dg/parse/namespace14.C: New.
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 243171)
+++ cp/parser.c (working copy)
@@ -18184,8 +18184,8 @@ cp_parser_namespace_definition (cp_parser* parser)
               cp_parser_error (parser, "nested identifier required");
               break;
             }
-          ++nested_definition_count;
-          push_namespace (identifier);
+         if (push_namespace (identifier))
+           ++nested_definition_count;
         }
     }
 
Index: testsuite/g++.dg/parse/namespace14.C
===================================================================
--- testsuite/g++.dg/parse/namespace14.C        (revision 0)
+++ testsuite/g++.dg/parse/namespace14.C        (working copy)
@@ -0,0 +1,6 @@
+// PR c++/78637
+
+namespace X {
+class Y;
+}
+namespace X::Y z;  // { dg-error "namespace|expected|type" }