Using icpc (ICC) 19.0.1.144 20181018. The following (stand alone) code compiles and links as expected when using
"icpc -std=c++17 error.cpp -o exec"
However, building a debug executable by turning on either -g or -O0 flag results in a linker error.
// error.cpp #include <vector> constexpr bool decider = false; void Function() { std::vector<unsigned long long> v1; if constexpr( decider ) { if( false ) {} std::vector<unsigned long long> v2 = v1; } } int main() {return 0;}