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Clean up the logic in is_min_const_fn

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This commit is contained in:
Oliver Scherer 2018-11-30 18:07:51 +01:00
parent ae0b00cada
commit b75d5f1867
1 changed files with 18 additions and 13 deletions
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31
src/librustc/ty/constness.rs
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@ -40,19 +40,24 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
/// Returns true if this function must conform to `min_const_fn`
pub fn is_min_const_fn(self, def_id: DefId) -> bool {
if self.features().staged_api {
// some intrinsics are waved through if called inside the
// standard library. Users never need to call them directly
if let abi::Abi::RustIntrinsic = self.fn_sig(def_id).abi() {
assert!(!self.is_const_fn(def_id));
match &self.item_name(def_id).as_str()[..] {
| "size_of"
| "min_align_of"
| "needs_drop"
=> return true,
_ => {},
}
// some intrinsics are waved through if called inside the
// standard library. Users never need to call them directly
if let abi::Abi::RustIntrinsic = self.fn_sig(def_id).abi() {
match &self.item_name(def_id).as_str()[..] {
| "size_of"
| "min_align_of"
| "needs_drop"
=> return true,
_ => {},
}
}
// Bail out if the signature doesn't contain `const`
if !self.is_const_fn_raw(def_id) {
return false;
}
if self.features().staged_api {
// in order for a libstd function to be considered min_const_fn
// it needs to be stable and have no `rustc_const_unstable` attribute
self.is_const_fn_raw(def_id) && match self.lookup_stability(def_id) {
@ -66,7 +71,7 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
}
} else {
// users enabling the `const_fn` feature gate can do what they want
self.is_const_fn_raw(def_id) && !self.features().const_fn
!self.features().const_fn
}
}
}