[phoe-krk]

Not really an error, since it is syntactically valid C++. It could definitely trigger a compiler warning, though.

[rini17]

Code that violates C++ static typing rules can be syntactically valid too, yet noone is proposing it should be only a warning.

(I find this the most weird thing about C/C++ culture: they are so proud it is static typed, yet oblivious to all the other problems and traps/memory unsafety/undefined behavior/etc.)