make .if short-circuit evaluation

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

I'm probably doing something stupidly wrong, but man make says:
	As in C, make will only evaluate a conditional as far as is necessary to
	determine its value.
however,
	x= /nonexistent
	.if exists(${x}) && ${x:sh} != 0
	.endif
complains
	sh: /nonexistent: not found

what am I missing?