squiid/rust
1
0
Fork 0
Code Issues Pull requests Projects Activity

Factor out conservative_is_privately_uninhabited

Browse source
This commit is contained in:
Cameron Steffen 2022-10-23 17:32:40 -05:00
parent 34cbe72780
commit cc8dddbac9
11 changed files with 25 additions and 81 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
compiler/rustc_borrowck/src/type_check/mod.rs
View file

@ -1564,10 +1564,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
}
}
None => {
if !self
.tcx()
.conservative_is_privately_uninhabited(self.param_env.and(sig.output()))
{
if !sig.output().is_privately_uninhabited(self.tcx(), self.param_env) {
span_mirbug!(self, term, "call to converging function {:?} w/o dest", sig);
}
}

11
compiler/rustc_middle/src/query/mod.rs
View file

@ -2078,17 +2078,6 @@ rustc_queries! {
desc { "normalizing opaque types in `{:?}`", key }
}
/// Checks whether a type is definitely uninhabited. This is
/// conservative: for some types that are uninhabited we return `false`,
/// but we only return `true` for types that are definitely uninhabited.
/// `ty.conservative_is_privately_uninhabited` implies that any value of type `ty`
/// will be `Abi::Uninhabited`. (Note that uninhabited types may have nonzero
/// size, to account for partial initialisation. See #49298 for details.)
query conservative_is_privately_uninhabited(key: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool {
desc { "conservatively checking if `{}` is privately uninhabited", key.value }
remap_env_constness
}
query limits(key: ()) -> Limits {
desc { "looking up limits" }
}

7
compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
View file

@ -41,6 +41,13 @@ impl<'tcx> InhabitedPredicate<'tcx> {
self.apply_inner(tcx, param_env, &|_| Err(())).ok()
}
/// Same as `apply`, but `NotInModule(_)` predicates yield `false`. That is,
/// privately uninhabited types are considered always uninhabited.
pub fn apply_ignore_module(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> bool {
let Ok(result) = self.apply_inner::<!>(tcx, param_env, &|_| Ok(true));
result
}
fn apply_inner<E>(
self,
tcx: TyCtxt<'tcx>,

9
compiler/rustc_middle/src/ty/inhabitedness/mod.rs
View file

@ -169,6 +169,15 @@ impl<'tcx> Ty<'tcx> {
) -> bool {
self.inhabited_predicate(tcx).apply(tcx, param_env, module)
}
/// Returns true if the type is uninhabited without regard to visibility
pub fn is_privately_uninhabited(
self,
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
) -> bool {
!self.inhabited_predicate(tcx).apply_ignore_module(tcx, param_env)
}
}
/// N.B. this query should only be called through `Ty::inhabited_predicate`

6
compiler/rustc_mir_build/src/build/matches/simplify.rs
View file

@ -264,10 +264,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let irrefutable = adt_def.variants().iter_enumerated().all(|(i, v)| {
i == variant_index || {
self.tcx.features().exhaustive_patterns
&& v.inhabited_predicate(self.tcx, adt_def)
&& !v
.inhabited_predicate(self.tcx, adt_def)
.subst(self.tcx, substs)
.apply_any_module(self.tcx, self.param_env)
!= Some(true)
.apply_ignore_module(self.tcx, self.param_env)
}
}) && (adt_def.did().is_local()
|| !adt_def.is_variant_list_non_exhaustive());

2
compiler/rustc_mir_transform/src/generator.rs
View file

@ -1015,7 +1015,7 @@ fn insert_panic_block<'tcx>(
fn can_return<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool {
// Returning from a function with an uninhabited return type is undefined behavior.
if tcx.conservative_is_privately_uninhabited(param_env.and(body.return_ty())) {
if body.return_ty().is_privately_uninhabited(tcx, param_env) {
return false;
}

3
compiler/rustc_ty_utils/src/layout.rs
View file

@ -442,8 +442,7 @@ fn layout_of_uncached<'tcx>(
let element = cx.layout_of(element)?;
let size = element.size.checked_mul(count, dl).ok_or(LayoutError::SizeOverflow(ty))?;
let abi = if count != 0 && tcx.conservative_is_privately_uninhabited(param_env.and(ty))
{
let abi = if count != 0 && ty.is_privately_uninhabited(tcx, param_env) {
Abi::Uninhabited
} else {
Abi::Aggregate { sized: true }

2
compiler/rustc_ty_utils/src/layout_sanity_check.rs
View file

@ -12,7 +12,7 @@ pub(super) fn sanity_check_layout<'tcx>(
layout: &TyAndLayout<'tcx>,
) {
// Type-level uninhabitedness should always imply ABI uninhabitedness.
if cx.tcx.conservative_is_privately_uninhabited(cx.param_env.and(layout.ty)) {
if layout.ty.is_privately_uninhabited(cx.tcx, cx.param_env) {
assert!(layout.abi.is_uninhabited());
}

57
compiler/rustc_ty_utils/src/ty.rs
View file

@ -416,62 +416,6 @@ fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
node.fn_sig().map_or(hir::IsAsync::NotAsync, |sig| sig.header.asyncness)
}
/// Don't call this directly: use ``tcx.conservative_is_privately_uninhabited`` instead.
pub fn conservative_is_privately_uninhabited_raw<'tcx>(
tcx: TyCtxt<'tcx>,
param_env_and: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,
) -> bool {
let (param_env, ty) = param_env_and.into_parts();
match ty.kind() {
ty::Never => {
debug!("ty::Never =>");
true
}
ty::Adt(def, _) if def.is_union() => {
debug!("ty::Adt(def, _) if def.is_union() =>");
// For now, `union`s are never considered uninhabited.
false
}
ty::Adt(def, substs) => {
debug!("ty::Adt(def, _) if def.is_not_union() =>");
// Any ADT is uninhabited if either:
// (a) It has no variants (i.e. an empty `enum`);
// (b) Each of its variants (a single one in the case of a `struct`) has at least
// one uninhabited field.
def.variants().iter().all(|var| {
var.fields.iter().any(|field| {
let ty = tcx.bound_type_of(field.did).subst(tcx, substs);
tcx.conservative_is_privately_uninhabited(param_env.and(ty))
})
})
}
ty::Tuple(fields) => {
debug!("ty::Tuple(..) =>");
fields.iter().any(|ty| tcx.conservative_is_privately_uninhabited(param_env.and(ty)))
}
ty::Array(ty, len) => {
debug!("ty::Array(ty, len) =>");
match len.try_eval_usize(tcx, param_env) {
Some(0) | None => false,
// If the array is definitely non-empty, it's uninhabited if
// the type of its elements is uninhabited.
Some(1..) => tcx.conservative_is_privately_uninhabited(param_env.and(*ty)),
}
}
ty::Ref(..) => {
debug!("ty::Ref(..) =>");
// References to uninitialised memory is valid for any type, including
// uninhabited types, in unsafe code, so we treat all references as
// inhabited.
false
}
_ => {
debug!("_ =>");
false
}
}
}
pub fn provide(providers: &mut ty::query::Providers) {
*providers = ty::query::Providers {
asyncness,
@ -481,7 +425,6 @@ pub fn provide(providers: &mut ty::query::Providers) {
instance_def_size_estimate,
issue33140_self_ty,
impl_defaultness,
conservative_is_privately_uninhabited: conservative_is_privately_uninhabited_raw,
..*providers
};
}

2
src/test/ui/const-generics/conservative_is_privately_uninhabited_uses_correct_param_env-1.rs → src/test/ui/const-generics/inhabited-assoc-ty-ice-1.rs
View file

@ -2,7 +2,7 @@
#![feature(generic_const_exprs)]
#![allow(incomplete_features)]
// This tests that the `conservative_is_privately_uninhabited` fn doesn't cause
// This tests that the inhabited check doesn't cause
// ICEs by trying to evaluate `T::ASSOC` with an incorrect `ParamEnv`.
trait Foo {

2
src/test/ui/const-generics/conservative_is_privately_uninhabited_uses_correct_param_env-2.rs → src/test/ui/const-generics/inhabited-assoc-ty-ice-2.rs
View file

@ -2,7 +2,7 @@
#![feature(generic_const_exprs)]
#![allow(incomplete_features)]
// This tests that the `conservative_is_privately_uninhabited` fn doesn't cause
// This tests that the inhabited check doesn't cause
// ICEs by trying to evaluate `T::ASSOC` with an incorrect `ParamEnv`.
trait Foo {