[C++ Patch] PR 84792 ("[6/7/8 Regression] ICE with broken typedef of a struct")

[Paolo Carlini]

Hi,

I'm really happy to report that these 5 ugly lines are causing an actual 
bug. Seriously, not considering the formatting, the problem is that we 
really want to keep 'type' in sync, because we are using it below before 
returning. Note that we don't regress location-wise because either 
explicitly or implicitly we pass input_location anyway. Finishing 
testing on x86_64-linux.

Thanks, Paolo.

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

/cp
2018-04-04  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/84792
        * decl.c (grokdeclarator): Fix diagnostic about typedef name used
        as nested-name-specifier, keep type and TREE_TYPE (decl) in sync.

/testsuite
2018-04-04  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/84792
        * g++.dg/other/pr84792-1.C: New.
        * g++.dg/other/pr84792-2.C: Likewise.
Index: cp/decl.c
===================================================================
--- cp/decl.c   (revision 259104)
+++ cp/decl.c   (working copy)
@@ -11746,15 +11746,16 @@ grokdeclarator (const cp_declarator *declarator,
       if (reqs)
        error_at (location_of (reqs), "requires-clause on typedef");
 
+      if (id_declarator && declarator->u.id.qualifying_scope)
+       {
+         error ("typedef name may not be a nested-name-specifier");
+         type = error_mark_node;
+       }
+
       if (decl_context == FIELD)
        decl = build_lang_decl (TYPE_DECL, unqualified_id, type);
       else
        decl = build_decl (input_location, TYPE_DECL, unqualified_id, type);
-      if (id_declarator && declarator->u.id.qualifying_scope) {
-       error_at (DECL_SOURCE_LOCATION (decl), 
-                 "typedef name may not be a nested-name-specifier");
-       TREE_TYPE (decl) = error_mark_node;
-      }
 
       if (decl_context != FIELD)
        {
Index: testsuite/g++.dg/other/pr84792-1.C
===================================================================
--- testsuite/g++.dg/other/pr84792-1.C  (nonexistent)
+++ testsuite/g++.dg/other/pr84792-1.C  (working copy)
@@ -0,0 +1,6 @@
+struct A {};
+
+typedef struct
+{
+  virtual void foo() {}
+} A::B;  // { dg-error "typedef" }
Index: testsuite/g++.dg/other/pr84792-2.C
===================================================================
--- testsuite/g++.dg/other/pr84792-2.C  (nonexistent)
+++ testsuite/g++.dg/other/pr84792-2.C  (working copy)
@@ -0,0 +1,6 @@
+struct A {};
+
+typedef struct
+{
+  void foo() {}
+} A::B;  // { dg-error "typedef" }