mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Differentiate different defining uses of taits when they reference distinct generic parameters

Browse Source
This commit is contained in:
Santiago Pastorino 2021-06-07 18:12:43 -03:00
parent e386373514
commit 9e547b4464
No known key found for this signature in database
GPG Key ID: 8131A24E0C79EFAF
3 changed files with 38 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
compiler/rustc_trait_selection/src/opaque_types.rs
View File

@ -11,7 +11,7 @@ use rustc_infer::infer::free_regions::FreeRegionRelations;
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::{self, InferCtxt, InferOk};
use rustc_middle::ty::fold::{BottomUpFolder, TypeFoldable, TypeFolder, TypeVisitor};
use rustc_middle::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef};
use rustc_middle::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst};
use rustc_middle::ty::{self, OpaqueTypeKey, Ty, TyCtxt};
use rustc_span::Span;
@ -1007,7 +1007,9 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> {
),
};
if in_definition_scope {
return self.fold_opaque_ty(ty, def_id.to_def_id(), substs, origin);
let opaque_type_key =
OpaqueTypeKey { def_id: def_id.to_def_id(), substs };
return self.fold_opaque_ty(ty, opaque_type_key, origin);
}
debug!(
@ -1029,23 +1031,18 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> {
fn fold_opaque_ty(
&mut self,
ty: Ty<'tcx>,
def_id: DefId,
substs: SubstsRef<'tcx>,
opaque_type_key: OpaqueTypeKey<'tcx>,
origin: hir::OpaqueTyOrigin,
) -> Ty<'tcx> {
let infcx = self.infcx;
let tcx = infcx.tcx;
let OpaqueTypeKey { def_id, substs } = opaque_type_key;
debug!("instantiate_opaque_types: Opaque(def_id={:?}, substs={:?})", def_id, substs);
// Use the same type variable if the exact same opaque type appears more
// than once in the return type (e.g., if it's passed to a type alias).
if let Some(opaque_defn) = self
.opaque_types
.iter()
.find(|(opaque_type_key, _)| opaque_type_key.def_id == def_id)
.map(|(_, opaque_defn)| opaque_defn)
{
if let Some(opaque_defn) = self.opaque_types.get(&opaque_type_key) {
debug!("instantiate_opaque_types: returning concrete ty {:?}", opaque_defn.concrete_ty);
return opaque_defn.concrete_ty;
}

16
src/test/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn.rs Normal file
View File

@ -0,0 +1,16 @@
// https://github.com/rust-lang/rust/issues/73481
// This test used to cause unsoundness, since one of the two possible
// resolutions was chosen at random instead of erroring due to conflicts.
#![feature(min_type_alias_impl_trait)]
type X<A, B> = impl Into<&'static A>;
//~^ ERROR the trait bound `&'static B: From<&A>` is not satisfied
fn f<A, B: 'static>(a: &'static A, b: B) -> (X<A, B>, X<B, A>) {
(a, a)
}
fn main() {
println!("{}", <X<_, _> as Into<&String>>::into(f(&[1isize, 2, 3], String::new()).1));
}

15
src/test/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn.stderr Normal file
View File

@ -0,0 +1,15 @@
error[E0277]: the trait bound `&'static B: From<&A>` is not satisfied
--> $DIR/multiple-def-uses-in-one-fn.rs:7:16
|
LL | type X<A, B> = impl Into<&'static A>;
| ^^^^^^^^^^^^^^^^^^^^^ the trait `From<&A>` is not implemented for `&'static B`
|
= note: required because of the requirements on the impl of `Into<&'static B>` for `&A`
help: consider introducing a `where` bound, but there might be an alternative better way to express this requirement
|
LL | fn f<A, B: 'static>(a: &'static A, b: B) -> (X<A, B>, X<B, A>) where &'static B: From<&A> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.