Rule 19.4 Does "#define XY -1" violate 19.4

[SimonB]

I'm not surprised it's rejected. "-1" isn't an integer literal, it's the unary minus operator applied to a literal. This means that it's an expression and should be parenthesised.

I can't think of any cases where using it gives a surprisingly wrong answer, but it does allow things to compile that look wrong, such as:-

Code:

    int b = 3 XY;

Simon