[Bug c++/95455] New: ICE in capture with initializer in requires block

[Bug c++/95455] New: ICE in capture with initializer in requires block

[bhalevy at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

            Bug ID: 95455
           Summary: ICE in capture with initializer in requires block
           Product: gcc
           Version: 10.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bhalevy at gmail dot com
  Target Milestone: ---

Created attachment 48650
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48650&action=edit
Preprocessed source

Compiling the following code hits ICE, as follows:

testcase.cc:
void f() {
    int foo;
    requires () {
        [bar = foo] {};
    };
}

$ g++ --std=gnu++20 testcase.cc
testcase.cc: In function ‘void f()’:
testcase.cc:4:16: internal compiler error: Segmentation fault
    4 |         [bar = foo] {};
      |                ^~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://bugzilla.redhat.com/bugzilla> for instructions.
Preprocessed source stored into /tmp/ccVYMnnA.out file, please attach this to
your bugreport.

[Bug c++/95455] ICE in capture with initializer in requires block

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
                 CC|                            |marxin at gcc dot gnu.org
   Last reconfirmed|                            |2020-06-01
             Status|UNCONFIRMED                 |WAITING

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed, is it a valid or invalid source?

[Bug c++/95455] ICE in capture with initializer in requires block

[avi@cloudius-systems.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

--- Comment #2 from Avi Kivity <avi@cloudius-systems.com> ---
Appears to be invalid. Clang rejects it even after some massaging (lambda in
unevaluated context).

[Bug c++/95455] ICE in capture with initializer in requires block

[avi@cloudius-systems.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

--- Comment #3 from Avi Kivity <avi@cloudius-systems.com> ---
Here's a valid version (which gcc accepts):

void f() {
    int foo = 4;
    auto lambda = [bar = foo] {};
    static_assert(requires (decltype(lambda) x) {
        x;
    });
}

[Bug c++/95455] ICE in capture with initializer in requires block

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
           Keywords|                            |ice-on-invalid-code

[Bug c++/95455] ICE in capture with initializer in requires block

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Lambdas in unevaluated contexts should be valid since P0315R4 which is (so far)
only implemented in GCC but not clang nor other compilers.
So I'm not sure about the invalid classification.

[Bug c++/95455] ICE in capture with initializer in requires block

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Clang gives:
<source>:5:16: error: reference to local variable 'foo' declared in enclosing
function 'f'
        [bar = foo] {};
               ^
<source>:3:9: note: 'foo' declared here
    int foo;
        ^

[Bug c++/95455] ICE in capture with initializer in requires block

[egor.pugin at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95455

Egor Pugin <egor.pugin at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |egor.pugin at gmail dot com

--- Comment #6 from Egor Pugin <egor.pugin at gmail dot com> ---
10.5 - ice
11.4 - ice
12.3 - ok
13.2 - ok
14.x - ice