bugprone-suspicious-include

The check detects various cases when an include refers to what appears to be an implementation file, which often leads to hard-to-track-down ODR violations.

Examples:

#include "Dinosaur.hpp"     // OK, .hpp files tend not to have definitions.
#include "Pterodactyl.h"    // OK, .h files tend not to have definitions.
#include "Velociraptor.cpp" // Warning, filename is suspicious.
#include_next <stdio.c>     // Warning, filename is suspicious.