Justification

Empty statements are probably a bug (forgetting parentheses when calling a function?). Since all selection and iteration statements should have a compound statement as the body, a null body should have a comment suitably indented.

The other use for a null statement is to carry a label before a closing brace, but since labels are prohibited by this standard so such null statements are, by implication, also prohibited.

Example

if (i == 0); /* WRONG */
if (i == 0)
{
   ; /* WRONG */
}

if (i == 0) /* RIGHT */
{
   /* suitable comment */
}