change definitely unproductive cycles to error
builds on top of #136824 by adding a third variant to `PathKind` for paths which may change to be coinductive in the future but must not be so right now. Most notably, impl where-clauses of not yet coinductive traits.
With this, we can change cycles which are definitely unproductive to a proper error. This fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/114. This does not affect stable as we keep these cycles as ambiguous during coherence.
r? ````````@compiler-errors```````` ````````@nikomatsakis````````
```
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;
|
```
Only highlight unmatchable parameters at the definition site
Followup to #136497
This generally results more focused messages in the same vein as #99635 (see `test/ui/argument-suggestions/complex.rs`). There are still some cases (e.g. `test/ui/argument-suggestions/permuted_arguments.rs`) where it might be worth highlighting the arguments. This is mitigated by the fact that a suggestion with a suggested rearrangement is given.
r? `@compiler-errors`
handle global trait bounds defining assoc types
This also fixes the compare-mode for
- tests/ui/coherence/coherent-due-to-fulfill.rs
- tests/ui/codegen/mono-impossible-2.rs
- tests/ui/trivial-bounds/trivial-bounds-inconsistent-projection.rs
- tests/ui/nll/issue-61320-normalize.rs
I first considered the alternative to always prefer where-bounds during normalization, regardless of how the trait goal has been proven by changing `fn merge_candidates` instead. ecda83b30f/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs (L785)
This approach is more restrictive than behavior of the old solver to avoid mismatches between trait and normalization goals. This may be breaking in case the where-bound adds unnecessary region constraints and we currently don't ever try to normalize an associated type. I would like to detect these cases and change the approach to exactly match the old solver if required. I want to minimize cases where attempting to normalize in more places causes code to break.
r? `@compiler-errors`
Don't pick `T: FnPtr` nested goals as the leaf goal in diagnostics for new solver
r? `@lcnr`
See `tests/ui/traits/next-solver/diagnostics/dont-pick-fnptr-bound-as-leaf.rs` for a minimized example of what code this affects the diagnostics off. The output of running nightly `-Znext-solver` on that test is the following:
```
error[E0277]: the trait bound `Foo: Trait` is not satisfied
--> src/lib.rs:14:20
|
14 | requires_trait(Foo);
| -------------- ^^^ the trait `FnPtr` is not implemented for `Foo`
| |
| required by a bound introduced by this call
|
note: required for `Foo` to implement `Trait`
--> src/lib.rs:7:16
|
7 | impl<T: FnPtr> Trait for T {}
| ----- ^^^^^ ^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `requires_trait`
--> src/lib.rs:11:22
|
11 | fn requires_trait<T: Trait>(_: T) {}
| ^^^^^ required by this bound in `requires_trait`
```
Part of rust-lang/trait-system-refactor-initiative#148
Rollup of 12 pull requests
Successful merges:
- #129409 (Expand std::os::unix::fs::chown() doc with a warning)
- #133320 (Add release notes for Rust 1.83.0)
- #133368 (Delay a bug when encountering an impl with unconstrained generics in `codegen_select`)
- #133428 (Actually use placeholder regions for trait method late bound regions in `collect_return_position_impl_trait_in_trait_tys`)
- #133512 (Add `as_array` and `as_mut_array` conversion methods to slices.)
- #133519 (Check `xform_ret_ty` for WF in the new solver to improve method winnowing)
- #133520 (Structurally resolve before applying projection in borrowck)
- #133534 (extend group-forbid-always-trumps-cli test)
- #133537 ([rustdoc] Fix new clippy lints)
- #133543 ([AIX] create shim for lgammaf_r)
- #133547 (rustc_span: Replace a `HashMap<_, ()>` with `HashSet`)
- #133550 (print generated doc paths)
r? `@ghost`
`@rustbot` modify labels: rollup
Structurally resolve before applying projection in borrowck
As far as I can tell, all other `.normalize` calls in borrowck are noops and can remain that way. This is the only one that actually requires structurally resolving the type.
r? lcnr
