https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77563
Bug ID: 77563
Summary: explicit constructor breaks narrowing conversion
overload resolution
Product: gcc
Version: 6.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: arnetheduck at gmail dot com
Target Milestone: ---
In the following snippet, an error should be emitted - instead, the compiler
prints a warning and keeps compiling, and simply skips the second call to f (!)
in the resulting executable:
#include <stdint.h>
#include <stdio.h>
struct A {
A(int32_t a) {}
A(uint32_t a) {} // Comment to make it work
explicit A(int64_t a) {} // Comment to make it work
};
void f(A a) { printf("hello\n"); }
int main(int, char**) {
f(2);
f(3l);
}
/opt/gcc62/bin/g++ -std=gnu++11 explicit.cpp
explicit.cpp: In function ‘int main(int, char**)’:
explicit.cpp:11:6: note: initializing argument 1 of ‘void f(A)’
void f(A a) { printf("hello\n"); }
^
With either marked constructor commented, compiles correctly and gives the
expected output ("hello" x 2 or ambiguity error).
