[Bug c++/65072] Segfault when parsing dectlype in trailing return type

["trippels at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65072

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|Archlinux Kernel 3.16.3,    |
                   |Intel x86_64                |
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-02-15
                 CC|                            |trippels at gcc dot gnu.org
               Host|Archlinux Kernel 3.16.3,    |
                   |Intel x86_64                |
     Ever confirmed|0                           |1

--- Comment #2 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Attached testcase only crashes with gcc-4.8 and gcc-4.9.
Reduced testcase crashes with all supported versions:

markus@x4 testc % cat main.ii
template <typename> class CMatrix44
{
  struct
  {
    int xx;
  };
  auto operator*(const CMatrix44 m) -> CMatrix44<decltype (m.xx)>;
};
using CMatrix44f = CMatrix44<float>;
void fn1 (const CMatrix44<float>);
CMatrix44f a;

markus@x4 testc % /g++ -c -std=c++11 main.ii
main.ii: In instantiation of âclass CMatrix44<float>â:
main.ii:12:12:   required from here
main.ii:7:8: internal compiler error: Segmentation fault
   auto operator*(const CMatrix44 m) -> CMatrix44<decltype (m.xx)>;
        ^
0xca24ff crash_signal
        ../../gcc/gcc/toplev.c:383
0x75a4e0 build_class_member_access_expr(tree_node*, tree_node*, tree_node*,
bool, int)
        ../../gcc/gcc/cp/typeck.c:2319
0x75a8d6 build_class_member_access_expr(tree_node*, tree_node*, tree_node*,
bool, int)
        ../../gcc/gcc/cp/typeck.c:2409
0x75b19b finish_class_member_access_expr(tree_node*, tree_node*, bool, int)
        ../../gcc/gcc/cp/typeck.c:2813
0x6713f0 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:15446
0x675276 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:12530
0x68bb1a tsubst_template_args
        ../../gcc/gcc/cp/pt.c:10257
0x6833c0 tsubst_aggr_type
        ../../gcc/gcc/cp/pt.c:10454
0x6757db tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:11909
0x68a598 tsubst_function_type
        ../../gcc/gcc/cp/pt.c:11614
0x675916 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:12357
0x6838de tsubst_decl
        ../../gcc/gcc/cp/pt.c:10845
0x675d36 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:11830
0x6a8900 instantiate_class_template_1
        ../../gcc/gcc/cp/pt.c:9374
0x6a8900 instantiate_class_template(tree_node*)
        ../../gcc/gcc/cp/pt.c:9688
0x73f56b complete_type(tree_node*)
        ../../gcc/gcc/cp/typeck.c:146
0x6222b7 start_decl_1(tree_node*, bool)
        ../../gcc/gcc/cp/decl.c:4898
0x641167 start_decl(cp_declarator const*, cp_decl_specifier_seq*, int,
tree_node*, tree_node*, tree_node**)
        ../../gcc/gcc/cp/decl.c:4861
0x72cde5 cp_parser_init_declarator
        ../../gcc/gcc/cp/parser.c:17153
0x72ebbc cp_parser_simple_declaration
        ../../gcc/gcc/cp/parser.c:11592
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