re PR c++/81247 (ICE on invalid C++ code with malformed namespace declaration: in do_push_nested_namespace, at cp/name-lookup.c:6002)

	PR c++/81247
	* parser.c (cp_parser_namespace_definition): Immediately close the
	namespace if there's no open-brace.
	* name-lookup.c (do_pushdecl): Reset OLD when pushing into new
	namespace.

From-SVN: r249804

7 files changed, 63 insertions, 6 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 2c29f1e..17da1c5 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2017-06-29  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/81247
+	* parser.c (cp_parser_namespace_definition): Immediately close the
+	namespace if there's no open-brace.
+	* name-lookup.c (do_pushdecl): Reset OLD when pushing into new
+	namespace.
+
 2017-06-29  Jason Merrill  <jason@redhat.com>
 
 	PR c++/81164 - ICE with invalid inherited constructor.
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index f15c811..4beab85 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -2422,6 +2422,9 @@ do_pushdecl (tree decl, bool is_friend)
 	{
 	  ns = current_namespace;
 	  slot = find_namespace_slot (ns, name, true);
+	  /* Update OLD to reflect the namespace we're going to be
+	     pushing into.  */
+	  old = MAYBE_STAT_DECL (*slot);
 	}
 
       old = update_binding (level, binding, slot, old, decl, is_friend);
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 31840d6..375cd0a 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -18397,13 +18397,14 @@ cp_parser_namespace_definition (cp_parser* parser)
   warning  (OPT_Wnamespaces, "namespace %qD entered", current_namespace);
 
   /* Look for the `{' to validate starting the namespace.  */
-  cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE);
-
-  /* Parse the body of the namespace.  */
-  cp_parser_namespace_body (parser);
+  if (cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+    {
+      /* Parse the body of the namespace.  */
+      cp_parser_namespace_body (parser);
 
-  /* Look for the final `}'.  */
-  cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+      /* Look for the final `}'.  */
+      cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+    }
 
   if (has_visibility)
     pop_visibility (1);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 49a84d6..d44f1a1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-06-29  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/81247
+	* g++.dg/parse/pr81247-[abc].C: New.
+
 2017-06-29  Carl Love  <cel@us.ibm.com>
 
 	* gcc.target/powerpc/builtins-3-runnable.c (test_int_result,
diff --git a/gcc/testsuite/g++.dg/parse/pr81247-a.C b/gcc/testsuite/g++.dg/parse/pr81247-a.C
new file mode 100644
index 0000000..c5b22ab
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/pr81247-a.C
@@ -0,0 +1,13 @@
+// PR c++/81247 ICE
+
+namespace N  // { dg-message "previous declaration" }
+// { dg-error "expected" "" { target *-*-* } .+1 }
+template < typename T > class A
+{ // { dg-error "redeclared as different" }
+  template < T > friend class N;
+};
+
+void f ()
+{
+  A < int > a1; //  { dg-message "required from here" }
+}
diff --git a/gcc/testsuite/g++.dg/parse/pr81247-b.C b/gcc/testsuite/g++.dg/parse/pr81247-b.C
new file mode 100644
index 0000000..b2b035b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/pr81247-b.C
@@ -0,0 +1,14 @@
+// PR c++/81247 confused error
+
+namespace N { // { dg-message "previous declaration" }
+}
+
+template < typename T > class A
+{ // { dg-error "redeclared as different" }
+  template < T > friend class N;
+};
+
+void f ()
+{
+  A < int > a1;
+}
diff --git a/gcc/testsuite/g++.dg/parse/pr81247-c.C b/gcc/testsuite/g++.dg/parse/pr81247-c.C
new file mode 100644
index 0000000..32f41f2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/pr81247-c.C
@@ -0,0 +1,13 @@
+// PR c++/81247 confused error
+
+namespace N { // { dg-message "previous declaration" }
+  template < typename T > class A
+  { // { dg-error "conflicts with a previous" }
+    template < T > friend class N;
+  };
+}
+
+void f ()
+{
+  N::A < int > a1;
+}