class P def main is shared x = 1 y = 2 b = x ! y # .error. The left hand type of "!" is not nilable (it's "int") so the expression will always evaluate to the right hand side. print 5 ! 6 # .error. The left hand type of "!" is not nilable (it's "int") so the expression will always evaluate to the right hand side. b = x != y # .error. The left hand type of "!=" is not nilable (it's "int") so the expression will always evaluate to the right hand side. If you meant "does not equal" then use "<>". "a != b" means "a = a ! b" where "!" is an operator concerning nil. if x != y # .error. The left hand type of "!=" is not nilable (it's "int") so the expression will always evaluate to the right hand side. If you meant "does not equal" then use "<>". "a != b" means "a = a ! b" where "!" is an operator concerning nil. print 'different' x != y # .error. The left hand type of "!=" is not nilable (it's "int") so the expression will always evaluate to the right hand side. If you meant "does not equal" then use "<>". "a != b" means "a = a ! b" where "!" is an operator concerning nil. CobraCore.noOp(x, y, b)