https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94695
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:c51e31a06f2c740c55852a683aa7ffdc20417362 commit r11-5234-gc51e31a06f2c740c55852a683aa7ffdc20417362 Author: Marek Polacek <pola...@redhat.com> Date: Mon Nov 9 21:15:33 2020 -0500 c++: Extend -Wrange-loop-construct for binding-to-temp [PR94695] This patch finishes the second half of -Wrange-loop-construct I promised to implement: it warns when a loop variable in a range-based for-loop is initialized with a value of a different type resulting in a copy. For instance: int arr[10]; for (const double &x : arr) { ... } where in every iteration we have to create and destroy a temporary value of type double, to which we bind the reference. This could negatively impact performance. As per Clang, this doesn't warn when the range returns a copy, hence the glvalue_p check. gcc/ChangeLog: PR c++/94695 * doc/invoke.texi: Update the -Wrange-loop-construct description. gcc/cp/ChangeLog: PR c++/94695 * parser.c (warn_for_range_copy): Warn when the loop variable is initialized with a value of a different type resulting in a copy. gcc/testsuite/ChangeLog: PR c++/94695 * g++.dg/warn/Wrange-loop-construct2.C: New test.
