https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106940
Bug ID: 106940
Summary: Feature request: -Wsuggest-noexcept and
-Wsuggest-explicit
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: felix.von.s at posteo dot de
Target Milestone: ---
When writing classes, I routinely tend to forget that constructors can be used
for implicit conversions, unless marked explicit.
I also tend to forget about noexcept specifiers, which can lead to performance
pitfalls, especially with move constructors and move assignment operators.
So I would like a compiler warning that could remind me to consider such
concerns. In case of noexcept, I don’t particularly need full semantic
analysis of the body; a pure syntax check whether the specifier is present
should suffice. And in case of explicit, no other kind of check is possible,
obviously.
I imagine -Wsuggest-explicit could be suppressed for copy and move constructors
from the same type. I am undecided whether it should apply to conversion
operators, but leaning towards yes.
The warnings would be silenced by adding explicit specifiers: explicit(false)
and noexcept(false). Each warning should probably require the earliest
language version where the respective silencing is possible (C++20 and C++11,
respectively).
