Use `ALL_CAPS` for macro names only

Reason

To avoid confusing macros with names that obey scope and type rules.

Example

void f()
{
    const int SIZE{1000};  // Bad, use 'size' instead
    int v[SIZE];
}

Note

In particular, this avoids confusing macros with non-macro symbolic constants (see also Enum.5: Don't use ALL_CAPS for enumerators)

enum bad { BAD, WORSE, HORRIBLE }; // BAD

Enforcement

• Flag macros with lower-case letters
• Flag ALL_CAPS non-macro names