https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94264
Bug ID: 94264
Summary: Array-to-pointer conversion not performed on array
prvalues
Product: gcc
Version: 9.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ndkrempel at gmail dot com
Target Milestone: ---
I think the most clearcut example is:
int main() {
using T = int[];
T{1, 2} == nullptr;
}
This compiles fine with clang, and is supported by the standard: the ==
operator explicitly performs array-to-pointer conversion
(https://eel.is/c++draft/expr#eq-1), and array-to-pointer conversion is
explicitly defined for rvalue arrays (https://eel.is/c++draft/expr#conv.array).
Other examples (which again all compile with clang) are:
+T{1, 2};
Here the standard wording seems to have a minor bug, as unary "+" does not
explicitly perform the array-to-pointer conversion, and the general rubric for
applying it (https://eel.is/c++draft/expr#basic.lval-6) only applies to
glvalues as written.
T{1, 2} + 1;
Ditto.
*(T{1, 2} + 1);
Interesting as T{1, 2}[1] should be equivalent to this (modulo the value
category of the result, https://eel.is/c++draft/expr#sub), yet the former is
rejected by gcc and the latter accepted.
