Rehome 30 `tests/ui/issues/` tests to other subdirectories under `tests/ui/` [#3 of Batch #2]
Part of rust-lang/rust#133895
Methodology:
1. Refer to the previously written `tests/ui/SUMMARY.md`
2. Find an appropriate category for the test, using the original issue thread and the test contents.
3. Add the issue URL at the bottom (not at the top, as that would mess up stderr line numbers)
4. Rename the tests to make their purpose clearer
Inspired by the methodology that `@Kivooeo` was using.
r? `@jieyouxu`
When encountering an unmet trait bound, point at local type that doesn't implement the trait:
```
error[E0277]: the trait bound `Bar<T>: Foo` is not satisfied
--> $DIR/issue-64855.rs:9:19
|
LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ;
| ^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
|
help: the trait `Foo` is not implemented for `Bar<T>`
--> $DIR/issue-64855.rs:9:1
|
LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ;
| ^^^^^^^^^^^^^^^^^
```
Do not use effective_visibilities query for Adt types of a local trait while proving a where-clause
Partially fixrust-lang/rust#145611, but we should do something make cycle in this situation ICE.
Instead of using a query, call `&tcx.resolutions(()).effective_visibilities`.
r? `````@lcnr`````
cc `````@compiler-errors`````
Reject relaxed bounds inside associated type bounds (ATB)
**Reject** relaxed bounds — most notably `?Sized` — inside associated type bounds `TraitRef<AssocTy: …>`.
This was previously accepted without warning despite being incorrect: ATBs are *not* a place where we perform *sized elaboration*, meaning `TraitRef<AssocTy: …>` does *not* elaborate to `TraitRef<AssocTy: Sized + …>` if `…` doesn't contain `?Sized`. Therefore `?Sized` is meaningless. In no other (stable) place do we (intentionally) allow relaxed bounds where we don't also perform sized elab, this is highly inconsistent and confusing! Another point of comparison: For the desugared `$SelfTy: TraitRef, $SelfTy::AssocTy: …` we don't do sized elab either (and thus also don't allow relaxed bounds).
Moreover — as I've alluded to back in https://github.com/rust-lang/rust/pull/135841#pullrequestreview-2619462717 — some later validation steps only happen during sized elaboration during HIR ty lowering[^1]. Namely, rejecting duplicates (e.g., `?Trait + ?Trait`) and ensuring that `Trait` in `?Trait` is equal to `Sized`[^2]. As you can probably guess, on stable/master we don't run these checks for ATBs (so we allow even more nonsensical bounds like `Iterator<Item: ?Copy>` despite T-types's ruling established in the FCP'ed rust-lang/rust#135841).
This PR rectifies all of this. I cratered this back in 2025-01-10 with (allegedly) no regressions found ([report](https://github.com/rust-lang/rust/pull/135331#issuecomment-2585330783), [its analysis](https://github.com/rust-lang/rust/pull/135331#issuecomment-2585356422)). [However a contributor manually found two occurrences](https://github.com/rust-lang/rust/issues/135229#issuecomment-2581832852) of `TraitRef<AssocTy: ?Sized>` in small hobby projects (presumably via GH code search). I immediately sent downstream PRs: https://github.com/Gui-Yom/turbo-metrics/pull/14, https://github.com/ireina7/summon/pull/1 (however, the owners have showed no reaction so far).
I'm leaning towards banning these forms **without a FCW** because a FCW isn't worth the maintenance cost[^3]. Note that associated type bounds were stabilized in 1.79.0 (released 2024-06-13 which is 13 months ago), so the proliferation of ATBs shouldn't be that high yet. If you think we should do another crater run since the last one was 6 months ago, I'm fine with that.
Fixesrust-lang/rust#135229.
[^1]: I consider this a flaw in the implementation and [I've already added a huge FIXME](82a02aefe0/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs (L195-L207)).
[^2]: To be more precise, if the internal flag `-Zexperimental-default-bounds` is provided other "default traits" (needs internal feature `lang_items`) are permitted as well (cc closely related internal feature: `more_maybe_bounds`).
[^3]: Having to track this and adding an entire lint whose remnants would remain in the code base forever (we never *fully* remove lints).
`tests/ui/issues/`: The Issues Strike Back [3/N]
Some `tests/ui/issues/` housekeeping, to trim down number of tests directly under `tests/ui/issues/`. Part of https://github.com/rust-lang/rust/issues/133895.
r? ```@jieyouxu```
Having multiple relaxed bounds like `?Sized + ?Iterator` is actually *fine*.
We actually want to reject *duplicate* relaxed bounds like `?Sized + ?Sized`
because these most certainly represent a user error.
Note that this doesn't mean that we accept more code because a bound like
`?Iterator` is still invalid as it's not relaxing a *default* trait and
the only way to define / use more default bounds is under the experimental
and internal feature `more_maybe_bounds` plus `lang_items` plus unstable
flag `-Zexperimental-default-bounds` (historical context: for the longest
time, bounds like `?Iterator` were actually allowed and lead to a hard
warning).
Ultimately, this simply *reframes* the diagnostic. The scope of
`more_maybe_bounds` / `-Zexperimental-default-bounds` remains unchanged
as well.
* The phrasing "only does something for" made sense back when this
diagnostic was a (hard) warning. Now however, it's simply a hard
error and thus completely rules out "doing something".
* The primary message was way too long
* The new wording more closely mirrors the wording we use for applying
other bound modifiers (like `const` and `async`) to incompatible
traits.
* "all other traits are not bound by default" is no longer accurate
under Sized Hierarchy. E.g., traits and assoc tys are (currently)
bounded by `MetaSized` by default but can't be relaxed using
`?MetaSized` (instead, you relax it by adding `PointeeSized`).
* I've decided against adding any diagnositic notes or suggestions
for now like "trait `Trait` can't be relaxed as it's not bound by
default" which would be incorrect for `MetaSized` and assoc tys
as mentioned above) or "consider changing `?MetaSized` to
`PointeeSized`" as the Sized Hierarchy impl is still WIP)
When a trait bound fails due to the Self type parameter, adjust_fulfillment_errors
now correctly points to the corresponding function argument instead of incorrectly
pointing to other arguments.
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
On nightly, we mention the trait is unstable
```
error[E0277]: the trait bound `T: Unstable` is not satisfied
--> $DIR/unstable-trait-suggestion.rs:13:9
|
LL | foo(t)
| --- ^ the trait `Unstable` is not implemented for `T`
| |
| required by a bound introduced by this call
|
note: required by a bound in `foo`
--> $DIR/unstable-trait-suggestion.rs:9:11
|
LL | fn foo<T: Unstable>(_: T) {}
| ^^^^^^^^ required by this bound in `foo`
help: consider restricting type parameter `T` but it is an `unstable` trait
|
LL | pub fn demo<T: Unstable>(t: T) {
| ++++++++++
```
On stable, we don't suggest the trait at all
```
error[E0277]: the trait bound `T: Unstable` is not satisfied
--> $DIR/unstable-trait-suggestion.rs:13:9
|
LL | foo(t)
| --- ^ the trait `Unstable` is not implemented for `T`
| |
| required by a bound introduced by this call
|
note: required by a bound in `foo`
--> $DIR/unstable-trait-suggestion.rs:9:11
|
LL | fn foo<T: Unstable>(_: T) {}
| ^^^^^^^^ required by this bound in `foo`
```
Remove the "which is required by `{root_obligation}`" post-script in
"the trait `X` is not implemented for `Y`" explanation in E0277. This
information is already conveyed in the notes explaining requirements,
making it redundant while making the text (particularly in labels)
harder to read.
```
error[E0277]: the trait bound `NotCopy: Copy` is not satisfied
--> $DIR/wf-static-type.rs:10:13
|
LL | static FOO: IsCopy<Option<NotCopy>> = IsCopy { t: None };
| ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `NotCopy`
|
= note: required for `Option<NotCopy>` to implement `Copy`
note: required by a bound in `IsCopy`
--> $DIR/wf-static-type.rs:7:17
|
LL | struct IsCopy<T:Copy> { t: T }
| ^^^^ required by this bound in `IsCopy`
```
vs the prior
```
error[E0277]: the trait bound `NotCopy: Copy` is not satisfied
--> $DIR/wf-static-type.rs:10:13
|
LL | static FOO: IsCopy<Option<NotCopy>> = IsCopy { t: None };
| ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `NotCopy`, which is required by `Option<NotCopy>: Copy`
|
= note: required for `Option<NotCopy>` to implement `Copy`
note: required by a bound in `IsCopy`
--> $DIR/wf-static-type.rs:7:17
|
LL | struct IsCopy<T:Copy> { t: T }
| ^^^^ required by this bound in `IsCopy`
```
Instead of
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:20
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^ doesn't have a size known at compile-time
```
output
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:29
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
```
Note that the caller chooses a type for type param
```
error[E0308]: mismatched types
--> $DIR/return-impl-trait.rs:23:5
|
LL | fn other_bounds<T>() -> T
| - -
| | |
| | expected `T` because of return type
| | help: consider using an impl return type: `impl Trait`
| expected this type parameter
...
LL | ()
| ^^ expected type parameter `T`, found `()`
|
= note: expected type parameter `T`
found unit type `()`
= note: the caller chooses the type of T which can be different from ()
```
Tried to see if "expected this type parameter" can be replaced, but that goes all the way to `rustc_infer` so seems not worth the effort and can affect other diagnostics.
Revives #112088 and #104755.
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
