Annex F (informative) Core undefined behavior [ub]

F.5 [dcl]: Declarations [ub.dcl]

F.5.8[ub:dcl.attr.assume.false]
Specified in: [dcl.attr.assume]

If an assumption expression would not evaluate to true at the point where it appears the behavior is undefined.
[Example 1: int g(int x) { [[assume(x >= 0)]]; return x/32; } int f() { return g(-10); // undefined behavior, assumption in g is false } — end example]