https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104577
S. Davis Herring <herring at lanl dot gov> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |herring at lanl dot gov --- Comment #4 from S. Davis Herring <herring at lanl dot gov> --- The understood direction for CWG2459 makes it clear that class-type template parameters must indeed be copied; in fact, they have to be copied twice in some cases to guarantee that they have the correct value when user-provided constructors are involved.