https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81676
Bug ID: 81676
Summary: Wrong warning with unused-but-set-parameter within 'if
constexpr'
Product: gcc
Version: 7.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: benni.buch at gmail dot com
Target Milestone: ---
template < typename T >
int f(T v){
if constexpr(sizeof(T) == sizeof(int)){
return v;
}else{
return 0;
}
}
int main(){
f(0);
f('a');
}
This is a valid program which should not produce a warning. (Normal 'if'
doesn't produce a warning either.)
$ g++ -std=c++1z -Wunused-but-set-parameter gcc-warning.cpp
gcc-warning.cpp: In instantiation of 'int f(T) [with T = char]':
gcc-warning.cpp:12:7: required from here
gcc-warning.cpp:2:9: warning: parameter 'v' set but not used
[-Wunused-but-set-parameter]
int f(T v){
^
$ g++ --version
g++ (GCC) 7.1.1 20170724
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
