https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96761
Bug ID: 96761
Summary: "error: call of overloaded ‘func(size_t)’ is
ambiguous" when argument is size_t(0) and func(int)
and func(const char *) are visible
Product: gcc
Version: 9.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: darktemplar at basealt dot ru
Target Milestone: ---
Following example fails to compile with g++-9.3.1:
#include <stdio.h>
#include <stddef.h>
void func(int arg)
{
printf("Called func(int) with arg = %d\n", arg);
}
void func(const char *arg)
{
printf("Called func(const char*) with arg = \"%s\"\n", arg);
}
int main(int argc, char **argv)
{
func(size_t(0));
func(0);
func(size_t(1));
func(size_t(1) - size_t(1));
#define emptystring ""
#define nonemptystring "non empty string"
func(emptystring);
func(sizeof(emptystring) - 1);
func(nonemptystring);
func(sizeof(nonemptystring) - 1);
return 0;
}
It fails to compile on line "func(size_t(0));" but lines "func(0);",
"func(size_t(1));", "func(size_t(1) - size_t(1));" and
"func(sizeof(emptystring) - 1);" are compiled fine. This result looks
inconsistent.
Compilation result is:
$ g++ test.cpp -o test
test.cpp: In function ‘int main(int, char**)’:
test.cpp:16:16: error: call of overloaded ‘func(size_t)’ is ambiguous
16 | func(size_t(0));
| ^
test.cpp:4:6: note: candidate: ‘void func(int)’
4 | void func(int arg)
| ^~~~
test.cpp:9:6: note: candidate: ‘void func(const char*)’
9 | void func(const char *arg)
| ^~~~
Expected result:
Successful compilation, with "func(int)" being chosen for "func(size_t(0))"
call.
g++ version:
$ LC_ALL=C g++ --version
x86_64-alt-linux-g++ (GCC) 9.3.1 20200518 (ALT Sisyphus 9.3.1-alt1)
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