Essential type of enumerated constants

[psusi]

What is the essential type of an enumerated constant? I believe it should be integer constant, and rule 10.3 seems to agree since it says this expression is compliant:

s8a = K1; /* constant value fits */

However, my static analyzer insists that this is a violation:

Code:

enum list {
ONE,
TWO,
THREE,
}

int c;
for( c = 0; c < THREE; c++ )  /* THREE is an integer constant so comparing it with c, an int, is not a violation */
....