https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114006
Bug ID: 114006
Summary: False positive diagnostic -Wpedantic for zero-size
arrays, most vexing parse
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: janschultke at googlemail dot com
Target Milestone: ---
I got a false positive warning when compiling LLVM with g++. Here is a minimal
repro:
struct string {
const char* data;
string operator+(const char*);
};
int LLVMFuzzerInitialize(int*, char***argv) {
string ExitOnErr(string(*argv[0]) + ": error:");
return 0;
}
<source>: In function 'int LLVMFuzzerInitialize(int*, char***)':
<source>:7:35: warning: ISO C++ forbids zero-size array 'argv' [-Wpedantic]
7 | string ExitOnErr(string(*argv[0]) + ": error:");
|
It looks like GCC thinks that this is a most vexing parse; i.e. it thinks that
argv[0] is a declarator, not a subscript operator. This cannot be correct
because the next expression is + ": error" so this cannot be parsed as a
function declaration.
I suspect that the diagnostic for zero-size arrays is prematurely emitted,
before it's actually known whether this is a function declaration or not.
