https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118482
Bug ID: 118482
Summary: Mutually dependent decltype ICE
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pashade1 at yahoo dot com
CC: ewlu at rivosinc dot com
Target Milestone: ---
GCC encounters an ICE (segfault) when getting the name of the following type
using `typeid()` (see Godbolt link: https://godbolt.org/z/TEaYE7veb, where
clang can compile this).
```
using what_type = decltype(
[](this auto&& self,
decltype([](decltype(self)&){}) x = {}){ return x; }());
#include <typeinfo>
auto& info = typeid(what_type);
```
Attempting to use an instance of this type also causes a compiler segfault (see
Godbolt link: https://godbolt.org/z/5x6sn7d8z, where clang also fails to
compile this).
```
using what_type = decltype(
[](this auto&& self,
decltype([](decltype(self)&){}) x = {}){ return x; }());
what_type x;
int main() {
if (x) return 1;
}
```
Both fail for versions 14.1, 14.2, and trunk available on Godbolt. The pattern
requires deducing this (C++23), so these examples are expected to not compile
on any versions older than 14.0.
