https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101486
Bug ID: 101486
Summary: Rejects valid qualification conversion involving array
of unknown bound in function template argument [P0388]
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: leni536 at gmail dot com
Target Milestone: ---
Version:
g++
(Compiler-Explorer-Build-gcc-48e8a7a677b8356df946cd12fbb215538828e747-binutils-2.36.1)
12.0.0 20210707 (experimental)
Flags: -std=c++20 -pedantic-errors
Observed behavior:
Rejects the following code:
```
template <typename T>
void f1(const T(*)[10]);
template <typename T>
void f2(T(*)[]);
void bar(int (*ptr)[10]) {
f1(ptr); // accepts
f2(ptr); // rejects
}
```
Expected behavior:
Accept both function calls. Qualification conversions are allowed when deducing
template arguments in a pointer function parameter
(https://timsong-cpp.github.io/cppwp/n4868/temp.deduct#call-4.2). As of C++20
(P0388) converting `int (*)[10]` to `int (*)[]` is a valid qualification
conversion.
Exhibits:
https://godbolt.org/z/rcbMhEf45
