[Bug c++/79050] [5/6/7 Regression] ICE: tree code 'template_type_parm' is not supported in LTO streams

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79050

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |5.5

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
THe function type of 'foo', written via writing the BLOCK tree of main.

(gdb) p debug_tree (t)
 <function_type 0x7ffff6a0ef18
    type <template_type_parm 0x7ffff6a0ee70 auto VOID
        align 8 symtab 0 alias set -1 canonical type 0x7ffff6a0ee70
       index 0 level 1 orig_level 1
        chain <type_decl 0x7ffff6a10e40 auto>>
    QI
    size <integer_cst 0x7ffff68a2f78 type <integer_type 0x7ffff68c10a8
bitsizetype> constant 8>
    unit size <integer_cst 0x7ffff68a2f90 type <integer_type 0x7ffff68c1000
sizetype> constant 1>
    align 8 symtab 0 alias set -1 canonical type 0x7ffff6a0ef18
    arg-types <tree_list 0x7ffff68b6d98
        value <void_type 0x7ffff68c1f18 void VOID
            align 8 symtab 0 alias set -1 canonical type 0x7ffff68c1f18
            pointer_to_this <pointer_type 0x7ffff68c90a8>>>>

Reduced testcase:

int main ()
{
   auto foo ();
}