Go to file
Esteban Küber 2c2f3ed2c4 Provide more context on recursive impl evaluation overflow
When an associated type `Self::Assoc` is part of a `where` clause,
we end up unable to evaluate the requirement and emit a E0275.

We now point at the associated type if specified in the `impl`. If
so, we also suggest using that type instead of `Self::Assoc`.
Otherwise, we explain that these are not allowed.

```
error[E0275]: overflow evaluating the requirement `<(T,) as Grault>::A == _`
  --> $DIR/impl-wf-cycle-1.rs:15:1
   |
LL | / impl<T: Grault> Grault for (T,)
LL | |
LL | | where
LL | |     Self::A: Baz,
LL | |     Self::B: Fiz,
   | |_________________^
LL |   {
LL |       type A = ();
   |       ------ associated type `<(T,) as Grault>::A` is specified here
   |
note: required for `(T,)` to implement `Grault`
  --> $DIR/impl-wf-cycle-1.rs:15:17
   |
LL | impl<T: Grault> Grault for (T,)
   |                 ^^^^^^     ^^^^
...
LL |     Self::A: Baz,
   |              --- unsatisfied trait bound introduced here
   = note: 1 redundant requirement hidden
   = note: required for `(T,)` to implement `Grault`
help: associated type for the current `impl` cannot be restricted in `where` clauses, remove this bound
   |
LL -     Self::A: Baz,
LL +     ,
   |
```
```
error[E0275]: overflow evaluating the requirement `<T as B>::Type == <T as B>::Type`
  --> $DIR/impl-wf-cycle-3.rs:7:1
   |
LL | / impl<T> B for T
LL | | where
LL | |     T: A<Self::Type>,
   | |_____________________^
LL |   {
LL |       type Type = bool;
   |       --------- associated type `<T as B>::Type` is specified here
   |
note: required for `T` to implement `B`
  --> $DIR/impl-wf-cycle-3.rs:7:9
   |
LL | impl<T> B for T
   |         ^     ^
LL | where
LL |     T: A<Self::Type>,
   |        ------------- unsatisfied trait bound introduced here
help: replace the associated type with the type specified in this `impl`
   |
LL |     T: A<bool>,
   |          ~~~~
```
```
error[E0275]: overflow evaluating the requirement `<T as Filter>::ToMatch == <T as Filter>::ToMatch`
  --> $DIR/impl-wf-cycle-4.rs:5:1
   |
LL | / impl<T> Filter for T
LL | | where
LL | |     T: Fn(Self::ToMatch),
   | |_________________________^
   |
note: required for `T` to implement `Filter`
  --> $DIR/impl-wf-cycle-4.rs:5:9
   |
LL | impl<T> Filter for T
   |         ^^^^^^     ^
LL | where
LL |     T: Fn(Self::ToMatch),
   |        ----------------- unsatisfied trait bound introduced here
note: associated types for the current `impl` cannot be restricted in `where` clauses
  --> $DIR/impl-wf-cycle-4.rs:7:11
   |
LL |     T: Fn(Self::ToMatch),
   |           ^^^^^^^^^^^^^
```

Fix #116925
2024-01-19 23:55:05 +00:00
.github
.reuse Rollup merge of #119189 - henrispriet:move-installing-from-source, r=Mark-Simulacrum 2024-01-13 22:35:08 +01:00
compiler Provide more context on recursive impl evaluation overflow 2024-01-19 23:55:05 +00:00
library Rollup merge of #120110 - invpt:patch-1, r=the8472 2024-01-19 08:15:05 +01:00
LICENSES
src Auto merge of #120121 - matthiaskrgr:rollup-razammh, r=matthiaskrgr 2024-01-19 16:26:37 +00:00
tests Provide more context on recursive impl evaluation overflow 2024-01-19 23:55:05 +00:00
.editorconfig
.git-blame-ignore-revs
.gitattributes
.gitignore
.gitmodules
.mailmap
Cargo.lock Rollup merge of #120039 - Nadrieril:remove-idx, r=compiler-errors 2024-01-17 20:21:23 +01:00
Cargo.toml
CODE_OF_CONDUCT.md
config.example.toml
configure
CONTRIBUTING.md
COPYRIGHT
INSTALL.md Move section "Installing from Source" to seperate file 2024-01-13 17:22:55 +01:00
LICENSE-APACHE
LICENSE-MIT
README.md Move section "Installing from Source" to seperate file 2024-01-13 17:22:55 +01:00
RELEASES.md
rust-bors.toml
rustfmt.toml
triagebot.toml Remove myself from review rotation 2024-01-18 21:04:31 +01:00
x
x.ps1
x.py

The Rust Programming Language

Rust Community

This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.

Note: this README is for users rather than contributors. If you wish to contribute to the compiler, you should read CONTRIBUTING.md instead.

Table of Contents

Quick Start

Read "Installation" from The Book.

Installing from source

If you really want to install from source (though this is not recommended), see INSTALL.md.

Getting Help

See https://www.rust-lang.org/community for a list of chat platforms and forums.

Contributing

See CONTRIBUTING.md.

License

Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.

See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.

Trademark

The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the "Rust Trademarks").

If you want to use these names or brands, please read the media guide.

Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.