Avoid `ALL_CAPS` names

Reason

Such names are commonly used for macros. Thus, ALL_CAPS name are vulnerable to unintended macro substitution.

Example

// somewhere in some header:
#define NE !=

// somewhere else in some other header:
enum Coord { N, NE, NW, S, SE, SW, E, W };

// somewhere third in some poor programmer's .cpp:
switch (direction) {
case N:
    // ...
case NE:
    // ...
// ...
}

Note

Do not use ALL_CAPS for constants just because constants used to be macros.

Enforcement

Flag all uses of ALL CAPS. For older code, accept ALL CAPS for macro names and flag all non-all-CAPS macro names.