https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101043
Bug ID: 101043
Summary: ICE in check_noexcept_r for lambda conditional
noexcept via requires expression
Product: gcc
Version: 10.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jbassett271 at gmail dot com
Target Milestone: ---
GCC has an internal compiler error for requires expressions inside the noexcept
clause of a lambda inside a templated function:
https://godbolt.org/z/oWhq9sf8M
template <typename T>
struct set {
bool contains(T const&) const { return true; }
};
template <typename T>
void intersect(set<T> const& lhs, set<T> const& rhs) {
auto f = [&]<typename T1>(T1&& _1) noexcept(requires {
{ rhs.contains(_1) } noexcept;
}) {
return rhs.contains(_1);
};
}
int main() {
set<int> lhs;
set<int> rhs;
intersect(lhs, rhs);
}
Error message:
<source>: In instantiation of 'void intersect(const set<T>&, const set<T>&)
[with T = int]':
<source>:18:21: required from here
<source>:9:7: internal compiler error: in check_noexcept_r, at cp/except.c:1123
9 | { rhs.contains(_1) } noexcept;
| ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
The commandline arguments, according to the Compiler Explorer link (cleaned a
little):
-g -o output.s -masm=intel -S -fdiagnostics-color=always -std=c++20 example.cpp
Clang compiles this fine.
I was able to replicate this bug in GCC versions 10.1, 10.2, 10.3, and 11.1.
