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Rollup merge of #133660 - compiler-errors:trait-obj-missing-assoc, r=lcnr

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Do not create trait object type if missing associated types

r? lcnr
This commit is contained in:
Matthias Krüger 2024-12-01 08:15:25 +01:00 • committed by GitHub
commit 4d5ad194d5
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GPG key ID: B5690EEEBB952194
15 changed files with 35 additions and 205 deletions
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6
compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs
View file

@ -219,11 +219,13 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
def_ids.retain(|def_id| !tcx.generics_require_sized_self(def_id));
}
self.complain_about_missing_assoc_tys(
if let Err(guar) = self.check_for_required_assoc_tys(
associated_types,
potential_assoc_types,
hir_trait_bounds,
);
) {
return Ty::new_error(tcx, guar);
}
// De-duplicate auto traits so that, e.g., `dyn Trait + Send + Send` is the same as
// `dyn Trait + Send`.

25
compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
View file

@ -714,14 +714,14 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
/// reasonable suggestion on how to write it. For the case of multiple associated types in the
/// same trait bound have the same name (as they come from different supertraits), we instead
/// emit a generic note suggesting using a `where` clause to constraint instead.
pub(crate) fn complain_about_missing_assoc_tys(
pub(crate) fn check_for_required_assoc_tys(
&self,
associated_types: FxIndexMap<Span, FxIndexSet<DefId>>,
potential_assoc_types: Vec<usize>,
trait_bounds: &[hir::PolyTraitRef<'_>],
) {
) -> Result<(), ErrorGuaranteed> {
if associated_types.values().all(|v| v.is_empty()) {
return;
return Ok(());
}
let tcx = self.tcx();
@ -739,7 +739,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
// Account for things like `dyn Foo + 'a`, like in tests `issue-22434.rs` and
// `issue-22560.rs`.
let mut trait_bound_spans: Vec<Span> = vec![];
let mut dyn_compatibility_violations = false;
let mut dyn_compatibility_violations = Ok(());
for (span, items) in &associated_types {
if !items.is_empty() {
trait_bound_spans.push(*span);
@ -752,13 +752,20 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
let violations =
dyn_compatibility_violations_for_assoc_item(tcx, trait_def_id, *assoc_item);
if !violations.is_empty() {
report_dyn_incompatibility(tcx, *span, None, trait_def_id, &violations).emit();
dyn_compatibility_violations = true;
dyn_compatibility_violations = Err(report_dyn_incompatibility(
tcx,
*span,
None,
trait_def_id,
&violations,
)
.emit());
}
}
}
if dyn_compatibility_violations {
return;
if let Err(guar) = dyn_compatibility_violations {
return Err(guar);
}
// related to issue #91997, turbofishes added only when in an expr or pat
@ -965,7 +972,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
}
}
err.emit();
Err(err.emit())
}
/// On ambiguous associated type, look for an associated function whose name matches the

12
tests/crashes/131668.rs
View file

@ -1,12 +0,0 @@
//@ known-bug: #131668
#![feature(generic_associated_types_extended)]
trait B {
type Y<const N: i16>;
}
struct Erase<T: B>(T);
fn make_static() {
Erase::<dyn for<'c> B<&'c ()>>(());
}

1
tests/ui/associated-type-bounds/overlaping-bound-suggestion.rs
View file

@ -5,7 +5,6 @@ trait Item {
pub struct Flatten<I> {
inner: <IntoIterator<Item: IntoIterator<Item: >>::IntoIterator as Item>::Core,
//~^ ERROR E0191
//~| ERROR E0223
}
fn main() {}

16
tests/ui/associated-type-bounds/overlaping-bound-suggestion.stderr
View file

@ -4,18 +4,6 @@ error[E0191]: the value of the associated types `Item` and `IntoIter` in `IntoIt
LL | inner: <IntoIterator<Item: IntoIterator<Item: >>::IntoIterator as Item>::Core,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: specify the associated types: `IntoIterator<Item: IntoIterator<Item: >, Item = Type, IntoIter = Type>`
error[E0223]: ambiguous associated type
--> $DIR/overlaping-bound-suggestion.rs:6:13
|
LL | inner: <IntoIterator<Item: IntoIterator<Item: >>::IntoIterator as Item>::Core,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: if there were a trait named `Example` with associated type `IntoIterator` implemented for `(dyn IntoIterator + 'static)`, you could use the fully-qualified path
|
LL | inner: <<(dyn IntoIterator + 'static) as Example>::IntoIterator as Item>::Core,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 1 previous error
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0191, E0223.
For more information about an error, try `rustc --explain E0191`.
For more information about this error, try `rustc --explain E0191`.

5
tests/ui/async-await/async-fn/dyn-pos.rs
View file

@ -3,9 +3,6 @@
#![feature(async_closure)]
fn foo(x: &dyn async Fn()) {}
//~^ ERROR the trait `AsyncFn` cannot be made into an object
//~| ERROR the trait `AsyncFnMut` cannot be made into an object
//~| ERROR the trait `AsyncFnMut` cannot be made into an object
//~| ERROR the trait `AsyncFnMut` cannot be made into an object
//~^ ERROR the trait `AsyncFnMut` cannot be made into an object
fn main() {}

48
tests/ui/async-await/async-fn/dyn-pos.stderr
View file

@ -13,52 +13,6 @@ note: for a trait to be "dyn-compatible" it needs to allow building a vtable to
&mut F
std::boxed::Box<F, A>
error[E0038]: the trait `AsyncFnMut` cannot be made into an object
--> $DIR/dyn-pos.rs:5:16
|
LL | fn foo(x: &dyn async Fn()) {}
| ^^^^^^^^^^ `AsyncFnMut` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $SRC_DIR/core/src/ops/async_function.rs:LL:COL
|
= note: the trait cannot be made into an object because it contains the generic associated type `CallRefFuture`
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `AsyncFnMut` for this new enum and using it instead:
&F
&mut F
std::boxed::Box<F, A>
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error[E0038]: the trait `AsyncFnMut` cannot be made into an object
--> $DIR/dyn-pos.rs:5:16
|
LL | fn foo(x: &dyn async Fn()) {}
| ^^^^^^^^^^ `AsyncFnMut` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $SRC_DIR/core/src/ops/async_function.rs:LL:COL
|
= note: the trait cannot be made into an object because it contains the generic associated type `CallRefFuture`
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `AsyncFnMut` for this new enum and using it instead:
&F
&mut F
std::boxed::Box<F, A>
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error[E0038]: the trait `AsyncFn` cannot be made into an object
--> $DIR/dyn-pos.rs:5:12
|
LL | fn foo(x: &dyn async Fn()) {}
| ^^^^^^^^^^^^^^ `AsyncFn` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $SRC_DIR/core/src/ops/async_function.rs:LL:COL
|
= note: the trait cannot be made into an object because it contains the generic associated type `CallRefFuture`
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `AsyncFn` for this new enum and using it instead:
&F
std::boxed::Box<F, A>
error: aborting due to 4 previous errors
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0038`.

3
tests/ui/dyn-compatibility/missing-assoc-type.rs
View file

@ -3,8 +3,5 @@ trait Foo {
}
fn bar(x: &dyn Foo) {} //~ ERROR the trait `Foo` cannot be made into an object
//~^ ERROR the trait `Foo` cannot be made into an object
//~| ERROR the trait `Foo` cannot be made into an object
//~| ERROR the trait `Foo` cannot be made into an object
fn main() {}

49
tests/ui/dyn-compatibility/missing-assoc-type.stderr
View file

@ -13,53 +13,6 @@ LL | type Bar<T>;
| ^^^ ...because it contains the generic associated type `Bar`
= help: consider moving `Bar` to another trait
error[E0038]: the trait `Foo` cannot be made into an object
--> $DIR/missing-assoc-type.rs:5:16
|
LL | fn bar(x: &dyn Foo) {}
| ^^^ `Foo` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/missing-assoc-type.rs:2:10
|
LL | trait Foo {
| --- this trait cannot be made into an object...
LL | type Bar<T>;
| ^^^ ...because it contains the generic associated type `Bar`
= help: consider moving `Bar` to another trait
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error[E0038]: the trait `Foo` cannot be made into an object
--> $DIR/missing-assoc-type.rs:5:16
|
LL | fn bar(x: &dyn Foo) {}
| ^^^ `Foo` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/missing-assoc-type.rs:2:10
|
LL | trait Foo {
| --- this trait cannot be made into an object...
LL | type Bar<T>;
| ^^^ ...because it contains the generic associated type `Bar`
= help: consider moving `Bar` to another trait
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error[E0038]: the trait `Foo` cannot be made into an object
--> $DIR/missing-assoc-type.rs:5:12
|
LL | fn bar(x: &dyn Foo) {}
| ^^^^^^^ `Foo` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/missing-assoc-type.rs:2:10
|
LL | trait Foo {
| --- this trait cannot be made into an object...
LL | type Bar<T>;
| ^^^ ...because it contains the generic associated type `Bar`
= help: consider moving `Bar` to another trait
error: aborting due to 4 previous errors
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0038`.

3
tests/ui/issues/issue-21950.rs
View file

@ -8,6 +8,5 @@ impl Add for i32 {
fn main() {
let x = &10 as &dyn Add;
//~^ ERROR E0393
//~| ERROR E0191
//~^ ERROR E0191
}

20
tests/ui/issues/issue-21950.stderr
View file

@ -7,22 +7,6 @@ LL | type Output;
LL | let x = &10 as &dyn Add;
| ^^^ help: specify the associated type: `Add<Output = Type>`
error[E0393]: the type parameter `Rhs` must be explicitly specified
--> $DIR/issue-21950.rs:10:25
|
LL | trait Add<Rhs=Self> {
| ------------------- type parameter `Rhs` must be specified for this
...
LL | let x = &10 as &dyn Add;
| ^^^
|
= note: because of the default `Self` reference, type parameters must be specified on object types
help: set the type parameter to the desired type
|
LL | let x = &10 as &dyn Add<Rhs>;
| +++++
error: aborting due to 1 previous error
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0191, E0393.
For more information about an error, try `rustc --explain E0191`.
For more information about this error, try `rustc --explain E0191`.

2
tests/ui/issues/issue-28344.rs
View file

@ -3,13 +3,11 @@ use std::ops::BitXor;
fn main() {
let x: u8 = BitXor::bitor(0 as u8, 0 as u8);
//~^ ERROR must be specified
//~| no function or associated item named
//~| WARN trait objects without an explicit `dyn` are deprecated
//~| WARN this is accepted in the current edition
let g = BitXor::bitor;
//~^ ERROR must be specified
//~| no function or associated item named
//~| WARN trait objects without an explicit `dyn` are deprecated
//~| WARN this is accepted in the current edition
}

27
tests/ui/issues/issue-28344.stderr
View file

@ -18,17 +18,8 @@ error[E0191]: the value of the associated type `Output` in `BitXor` must be spec
LL | let x: u8 = BitXor::bitor(0 as u8, 0 as u8);
| ^^^^^^ help: specify the associated type: `BitXor::<Output = Type>`
error[E0599]: no function or associated item named `bitor` found for trait object `dyn BitXor<_>` in the current scope
--> $DIR/issue-28344.rs:4:25
|
LL | let x: u8 = BitXor::bitor(0 as u8, 0 as u8);
| ^^^^^ function or associated item not found in `dyn BitXor<_>`
|
help: there is a method `bitxor` with a similar name, but with different arguments
--> $SRC_DIR/core/src/ops/bit.rs:LL:COL
warning: trait objects without an explicit `dyn` are deprecated
--> $DIR/issue-28344.rs:10:13
--> $DIR/issue-28344.rs:9:13
|
LL | let g = BitXor::bitor;
| ^^^^^^
@ -41,21 +32,11 @@ LL | let g = <dyn BitXor>::bitor;
| ++++ +
error[E0191]: the value of the associated type `Output` in `BitXor` must be specified
--> $DIR/issue-28344.rs:10:13
--> $DIR/issue-28344.rs:9:13
|
LL | let g = BitXor::bitor;
| ^^^^^^ help: specify the associated type: `BitXor::<Output = Type>`
error[E0599]: no function or associated item named `bitor` found for trait object `dyn BitXor<_>` in the current scope
--> $DIR/issue-28344.rs:10:21
|
LL | let g = BitXor::bitor;
| ^^^^^ function or associated item not found in `dyn BitXor<_>`
|
help: there is a method `bitxor` with a similar name
--> $SRC_DIR/core/src/ops/bit.rs:LL:COL
error: aborting due to 2 previous errors; 2 warnings emitted
error: aborting due to 4 previous errors; 2 warnings emitted
Some errors have detailed explanations: E0191, E0599.
For more information about an error, try `rustc --explain E0191`.
For more information about this error, try `rustc --explain E0191`.

2
tests/ui/suggestions/trait-hidden-method.rs
View file

@ -1,8 +1,6 @@
// #107983 - testing that `__iterator_get_unchecked` isn't suggested
// HELP included so that compiletest errors on the bad suggestion
pub fn i_can_has_iterator() -> impl Iterator<Item = u32> {
//~^ ERROR expected `Box<dyn Iterator>`
//~| HELP consider constraining the associated type
Box::new(1..=10) as Box<dyn Iterator>
//~^ ERROR the value of the associated type `Item`
//~| HELP specify the associated type

21
tests/ui/suggestions/trait-hidden-method.stderr
View file

@ -1,24 +1,9 @@
error[E0191]: the value of the associated type `Item` in `Iterator` must be specified
--> $DIR/trait-hidden-method.rs:6:33
--> $DIR/trait-hidden-method.rs:4:33
|
LL | Box::new(1..=10) as Box<dyn Iterator>
| ^^^^^^^^ help: specify the associated type: `Iterator<Item = Type>`
error[E0271]: expected `Box<dyn Iterator>` to be an iterator that yields `u32`, but it yields `<dyn Iterator as Iterator>::Item`
--> $DIR/trait-hidden-method.rs:3:32
|
LL | pub fn i_can_has_iterator() -> impl Iterator<Item = u32> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `u32`, found associated type
...
LL | Box::new(1..=10) as Box<dyn Iterator>
| ------------------------------------- return type was inferred to be `Box<dyn Iterator>` here
|
= note: expected type `u32`
found associated type `<dyn Iterator as Iterator>::Item`
= help: consider constraining the associated type `<dyn Iterator as Iterator>::Item` to `u32`
= note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
error: aborting due to 1 previous error
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0191, E0271.
For more information about an error, try `rustc --explain E0191`.
For more information about this error, try `rustc --explain E0191`.