bjoernager/rust
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ParamEnv should be const when ImplItem is within a const impl.

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Deadbeef 2021-11-29 22:21:38 +08:00
parent 8710a2e169
commit 87cd1ce6c1
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GPG key ID: 6D017A96D8E6C2F9
4 changed files with 58 additions and 30 deletions
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27
compiler/rustc_hir/src/hir.rs
View file

@ -3228,33 +3228,6 @@ impl<'hir> Node<'hir> {
}
}
/// Returns `Constness::Const` when this node is a const fn/impl/item.
pub fn constness_for_typeck(&self) -> Constness {
match self {
Node::Item(Item {
kind: ItemKind::Fn(FnSig { header: FnHeader { constness, .. }, .. }, ..),
..
})
| Node::TraitItem(TraitItem {
kind: TraitItemKind::Fn(FnSig { header: FnHeader { constness, .. }, .. }, ..),
..
})
| Node::ImplItem(ImplItem {
kind: ImplItemKind::Fn(FnSig { header: FnHeader { constness, .. }, .. }, ..),
..
})
| Node::Item(Item { kind: ItemKind::Impl(Impl { constness, .. }), .. }) => *constness,
Node::Item(Item { kind: ItemKind::Const(..), .. })
| Node::Item(Item { kind: ItemKind::Static(..), .. })
| Node::TraitItem(TraitItem { kind: TraitItemKind::Const(..), .. })
| Node::AnonConst(_)
| Node::ImplItem(ImplItem { kind: ImplItemKind::Const(..), .. }) => Constness::Const,
_ => Constness::NotConst,
}
}
pub fn as_owner(self) -> Option<OwnerNode<'hir>> {
match self {
Node::Item(i) => Some(OwnerNode::Item(i)),

38
compiler/rustc_ty_utils/src/ty.rs
View file

@ -287,7 +287,43 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
let hir_id = local_did.map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id));
let constness = match hir_id {
Some(hir_id) => tcx.hir().get(hir_id).constness_for_typeck(),
Some(hir_id) => match tcx.hir().get(hir_id) {
hir::Node::Item(hir::Item { kind: hir::ItemKind::Const(..), .. })
| hir::Node::Item(hir::Item { kind: hir::ItemKind::Static(..), .. })
| hir::Node::TraitItem(hir::TraitItem { kind: hir::TraitItemKind::Const(..), .. })
| hir::Node::AnonConst(_)
| hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. })
| hir::Node::ImplItem(hir::ImplItem {
kind: hir::ImplItemKind::Fn(hir::FnSig { header: hir::FnHeader { constness: hir::Constness::Const, .. }, .. }, ..),
..
}) => hir::Constness::Const,
hir::Node::ImplItem(hir::ImplItem {
kind: hir::ImplItemKind::TyAlias(..) | hir::ImplItemKind::Fn(..),
..
}) => {
let parent_hir_id = tcx.hir().get_parent_node(hir_id);
match tcx.hir().get(parent_hir_id) {
hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(hir::Impl { constness, .. }), .. }) => *constness,
_ => span_bug!(
tcx.def_span(parent_hir_id.owner),
"impl item's parent node is not an impl",
),
}
}
hir::Node::Item(hir::Item {
kind: hir::ItemKind::Fn(hir::FnSig { header: hir::FnHeader { constness, .. }, .. }, ..),
..
})
| hir::Node::TraitItem(hir::TraitItem {
kind: hir::TraitItemKind::Fn(hir::FnSig { header: hir::FnHeader { constness, .. }, .. }, ..),
..
})
| hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(hir::Impl { constness, .. }), .. }) => *constness,
_ => hir::Constness::NotConst,
},
None => hir::Constness::NotConst,
};

3
src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
View file

@ -1,6 +1,5 @@
// FIXME(fee1-dead): this should have a better error message
#![feature(const_trait_impl)]
// check-pass
struct NonConstAdd(i32);
impl std::ops::Add for NonConstAdd {
@ -17,7 +16,7 @@ trait Foo {
impl const Foo for NonConstAdd {
type Bar = NonConstAdd;
//TODO: ~^ ERROR
//~^ ERROR
}
trait Baz {

20
src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr Normal file
View file

@ -0,0 +1,20 @@
error[E0277]: cannot add `NonConstAdd` to `NonConstAdd`
--> $DIR/assoc-type.rs:18:5
|
LL | type Bar = NonConstAdd;
| ^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `NonConstAdd + NonConstAdd`
|
= help: the trait `Add` is not implemented for `NonConstAdd`
note: required by a bound in `Foo::Bar`
--> $DIR/assoc-type.rs:14:15
|
LL | type Bar: ~const std::ops::Add;
| ^^^^^^^^^^^^^^^^^^^^ required by this bound in `Foo::Bar`
help: consider introducing a `where` bound, but there might be an alternative better way to express this requirement
|
LL | impl const Foo for NonConstAdd where NonConstAdd: Add {
| ++++++++++++++++++++++
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.