[Bug c++/94255] template specialization in different namespace causes crash

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

Marek Polacek  changed:

   What|Removed |Added

 Resolution|--- |FIXED
 Status|ASSIGNED|RESOLVED

--- Comment #8 from Marek Polacek  ---
Fixed in GCC 11.

[Bug c++/94255] template specialization in different namespace causes crash

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

--- Comment #7 from CVS Commits  ---
The master branch has been updated by Marek Polacek :

https://gcc.gnu.org/g:21968d4ae067e3fa1c1728c8db26478e8ac8ad0b

commit r11-175-g21968d4ae067e3fa1c1728c8db26478e8ac8ad0b
Author: Marek Polacek 
Date:   Fri Apr 17 23:48:11 2020 -0400

c++: Fix crash with template spec in different namespace [PR94255]

This is an ICE on invalid, because we're specializing S::foo in the
wrong namespace.  cp_parser_class_specifier_1 parses S::foo in M
and then it tries to push the nested-name-specifier of foo, which is
S.  By that, we're breaking the assumption of push_inner_scope that
the pushed scope must be a scope nested inside current scope: current
scope is M, but the namespace context of S is N, and N is not nested
in M, so we fell into an infinite loop in push_inner_scope_r.

(cp_parser_class_head called check_specialization_namespace which already
gave a permerror.)

PR c++/94255
* parser.c (cp_parser_class_specifier_1): Check that the scope is
nested inside current scope before pushing it.

* g++.dg/template/spec41.C: New test.

[Bug c++/94255] template specialization in different namespace causes crash

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

--- Comment #6 from Marek Polacek  ---
Patch approved for GCC 11:
https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544081.html

[Bug c++/94255] template specialization in different namespace causes crash

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

Marek Polacek  changed:

   What|Removed |Added

 Status|NEW |ASSIGNED
   Assignee|unassigned at gcc dot gnu.org  |mpolacek at gcc dot 
gnu.org

--- Comment #5 from Marek Polacek  ---
Testing a patch.

[Bug c++/94255] template specialization in different namespace causes crash

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

Marek Polacek  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 CC||mpolacek at gcc dot gnu.org
 Ever confirmed|0   |1
   Last reconfirmed||2020-03-27

--- Comment #4 from Marek Polacek  ---
Confirmed, started with r0-113135-g28704289327e4295928663b5bab7953718f71bc1

[Bug c++/94255] template specialization in different namespace causes crash

[xerofoify at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

--- Comment #3 from Nicholas Krause  ---
I've managed to track this down to what appears to me to be a issue in:
tree
push_inner_scope (tree inner)
{
  tree outer = current_scope ();
  if (!outer)
outer = current_namespace;

  push_inner_scope_r (outer, inner);
  return outer;
}


I'm not certain if we should just check against NULL_TREE for outer or do we
need to also check against DECL_NAMESPACE as well. CCing Jason Merrill to take
a look at this with his comments.

[Bug c++/94255] template specialization in different namespace causes crash

[xerofoify at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

Nicholas Krause  changed:

   What|Removed |Added

 CC||jason at redhat dot com,
   ||xerofoify at gmail dot com

--- Comment #2 from Nicholas Krause  ---
I've managed to track this down to what appears to me to be a issue in:
tree
push_inner_scope (tree inner)
{
  tree outer = current_scope ();
  if (!outer)
outer = current_namespace;

  push_inner_scope_r (outer, inner);
  return outer;
}


I'm not certain if we should just check against NULL_TREE for outer or do we
need to also check against DECL_NAMESPACE as well. CCing Jason Merrill to take
a look at this with his comments.

[Bug c++/94255] template specialization in different namespace causes crash

[vince.a.bridgers at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

--- Comment #1 from Vince Bridgers  ---
The corrected code successfully compiles. Basically, making sure the template
specialization is in the correct namespace. 

namespace clang {
  class DynTypedNode {
  private:
template  struct BaseConverter;
template  struct ValueConverter {};
  };
  namespace ast_type_traits {
using DynTypedNode = ::clang::DynTypedNode;
  }; // end namespace ast_type_traits
}; // end namespace clang

namespace clang {
  //namespace ast_type_traits {
template <> struct DynTypedNode::BaseConverter : public
ValueConverter {};
  //}; // end namespace ast_type_traits
}; // end namespace clang

int main(void) {
return 0;
}