pub fn is_safe_to_expose_on_stable_const_fn(
tcx: TyCtxt<'_>,
def_id: DefId,
) -> bool
Expand description
Returns true
if the given const fn
is “safe to expose on stable”.
Panics if the given DefId
does not refer to a const fn
.
This is relevant within a staged_api
crate. Unlike with normal features, the use of unstable
const features recursively taints the functions that use them. This is to avoid accidentally
exposing e.g. the implementation of an unstable const intrinsic on stable. So we partition the
world into two functions: those that are safe to expose on stable (and hence may not use
unstable features, not even recursively), and those that are not.