https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86926
Bug ID: 86926
Summary: [Regression] ICE for a recursive generic lambda
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: v.reshetnikov at gmail dot com
Target Milestone: ---
/************************* BEGIN SOURCE *************************/
int main() {
constexpr auto f = [](auto self, auto n) {
if(n < 2) return n;
return self(self, n - 1) + self(self, n - 2);
};
constexpr auto fibonacci = [=](auto n) { return f(f, n); };
static_assert(fibonacci(7) == 13);
}
/************************** END SOURCE **************************/
Compile with -std=c++17.
EXPECTED: no errors.
ACTUAL:
<source>: In instantiation of 'main()::<lambda(auto:3)> [with auto:3 = int]':
<source>:11:30: required from here
<source>:9:54: internal compiler error: in build_over_call, at cp/call.c:8214
9 | constexpr auto fibonacci = [=](auto n) { return f(f, n); };
| ~^~~~~~
Tested with build 9.0.0 20180810 (experimental), appears to be a regression
from GCC 8.2. For comparison, the code also successfully compiles with Clang.
