[Bug c++/58597] New: [c++11] ICE with lambda in default argument of template function

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58597

            Bug ID: 58597
           Summary: [c++11] ICE with lambda in default argument of
                    template function
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: reichelt at gcc dot gnu.org

The following valid code snippet (compiled with "-std=c++11") triggers an ICE
since GCC 4.5.0 (when lambdas were introduced):

===============================================================
template<typename> struct A
{
  template<typename T> A(T, int = []{ return 0; }()) {}
};

A<int> a = 0;
===============================================================

bug.cc: In substitution of 'template<class T> A< <template-parameter-1-1>
>::A(T, int) [with T = int]':
bug.cc:6:12:   required from here
bug.cc:6:12: internal compiler error: in instantiate_template_1, at
cp/pt.c:15008
 A<int> a = 0;
            ^
0x5d0b93 instantiate_template_1
        ../../gcc/gcc/cp/pt.c:15008
0x5d0b93 instantiate_template(tree_node*, tree_node*, int)
        ../../gcc/gcc/cp/pt.c:15117
0x5d264a fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, bool, bool)
        ../../gcc/gcc/cp/pt.c:15466
0x53f0fc add_template_candidate_real
        ../../gcc/gcc/cp/call.c:2923
0x53ae69 add_template_candidate
        ../../gcc/gcc/cp/call.c:3020
0x53ae69 add_candidates
        ../../gcc/gcc/cp/call.c:5075
0x53bd40 build_user_type_conversion_1
        ../../gcc/gcc/cp/call.c:3484
0x546013 build_user_type_conversion(tree_node*, tree_node*, int, int)
        ../../gcc/gcc/cp/call.c:3653
0x6843da ocp_convert(tree_node*, tree_node*, int, int, int)
        ../../gcc/gcc/cp/cvt.c:865
0x6913dd expand_default_init
        ../../gcc/gcc/cp/init.c:1597
0x6913dd expand_aggr_init_1
        ../../gcc/gcc/cp/init.c:1766
0x693b79 build_aggr_init(tree_node*, tree_node*, int, int)
        ../../gcc/gcc/cp/init.c:1517
0x557da5 build_aggr_init_full_exprs
        ../../gcc/gcc/cp/decl.c:5543
0x557da5 check_initializer
        ../../gcc/gcc/cp/decl.c:5678
0x56aa5c cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        ../../gcc/gcc/cp/decl.c:6347
0x65196f cp_parser_init_declarator
        ../../gcc/gcc/cp/parser.c:16567
0x65207f cp_parser_simple_declaration
        ../../gcc/gcc/cp/parser.c:10986
0x653ee0 cp_parser_block_declaration
        ../../gcc/gcc/cp/parser.c:10867
0x65cf1e cp_parser_declaration
        ../../gcc/gcc/cp/parser.c:10764
0x65bc8a cp_parser_declaration_seq_opt
        ../../gcc/gcc/cp/parser.c:10650
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