Function is_as_ptr_valid 

pub fn is_as_ptr_valid(callee: Option<DefId>) -> bool

is_as_ptr restricted to the pointer-validity-establishing subset: as_ptr/as_mut_ptr, into_raw, and NonNull::cast — which expose a non-null, aligned, initialized backing pointer. Raw-pointer cast/ cast_mut/cast_const are excluded because they only reinterpret the address (preserving null-ness) and are left to MIR inlining.