`rustc` will start marking the suggestions for prefacing unused bindings
with underscores as "maybe incorrect", which makes them no longer auto
applicable by `rustfix`.
Change done at https://github.com/rust-lang/rust/pull/120470.
This adds a set of tests which validates various edge cases around how
`cargo fix` works in terms of calling `rustc` multiple times. This uses
a replacement of `rustc` so it doesn't depend on the behavior of rustc
itself which is not always stable.
Show feature resolver differences for dev-dependencies.
During the crater run for 2021, there was a package that failed to update in a confusing way. The issue is that a feature was removed in the new resolver, but only for a dev-dependency. The report displayed with `cargo fix --edition` did not say anything about that, so it took me a bit to figure it out. This changes it so that the report also includes changes to features of dev-dependencies. I honestly don't remember my thought process behind the original code.
For example, the offending package now says:
```
When building the following dependencies, the given features will no longer be used:
log v0.4.8 removed features: std
syn v0.15.44 (as host dependency) removed features: extra-traits, visit
The following differences only apply when building with dev-dependencies:
phf_shared v0.7.24 (as host dependency) removed features: unicase
```
And the error that happens after updating to 2021 is:
```
error[E0277]: the trait bound `UniCase<&str>: phf_shared::PhfHash` is not satisfied
--> /Users/eric/.cargo/registry/src/github.com-1ecc6299db9ec823/mime_guess-1.8.7/build.rs:37:21
|
37 | forward_map.entry(UniCase(key), &format!("{:?}", val));
| ^^^^^ the trait `phf_shared::PhfHash` is not implemented for `UniCase<&str>`
```
Hopefully developers will be able to see the note about the feature `unicase` being removed from `phf_shared`, and the error message about `UniCase` not implementing `PhfHash`, and connect the two together. Previously, the upgrade report didn't mention anything about `phf_shared`, and thus no clues on what went wrong.
Serialize `cargo fix`
This changes `cargo fix` so that it only fixes one crate at a time. Previously, it would allow concurrent fixing across packages. This caused a problem if a workspace uses things like `#[path]` or `include!()` of a shared file between packages. A real-world example of this is serde, which has [this](9c39115f82/serde_derive_internals/lib.rs (L43-L45)) which reuses the some source files between the `serde` and `serde_derive` packages. Modifying those files concurrently causes corruption and the fix will fail.
Closes#6528
This works by introspecting rustc's error output, using the JSON format
to determine whether it's a warning or error, then skipping it
altogether if it's a summary of the diagnostics printed.
Before:
```
src/main.rs:1:10: warning: trait objects without an explicit `dyn` are deprecated
src/main.rs:1:1: error[E0601]: `main` function not found in crate `wrong`
src/main.rs:1:9: error[E0038]: the trait `Clone` cannot be made into an object
error: aborting due to 2 previous errors; 1 warning emitted
error: could not compile `wrong`
```
After:
```
$ cargo check --message-format short
src/main.rs:1:10: warning: trait objects without an explicit `dyn` are deprecated
src/main.rs:1:1: error[E0601]: `main` function not found in crate `wrong`
src/main.rs:1:9: error[E0038]: the trait `Clone` cannot be made into an object
error: could not compile `wrong` due to 2 previous errors; 1 warning emitted
```
Fix rustc/rustdoc config values to be config-relative.
The `rustc`, `rustdoc`, `rustc_wrapper`, and `rustc_workspace_wrapper` config values (in the `[build]` table) were being interpreted literally. This caused a problem if you used a relative path like `foo/rustc`. This would be interpreted as a relative path from whatever cwd cargo launches rustc from, which changes for different scenarios, making it essentially unusuable (since crates.io dependencies wouldn't be buildable).
Additionally, due to https://github.com/rust-lang/rust/issues/37868, it is a bad idea to use relative paths.
This changes it so that those paths are config-relative. Bare names (like "my-rustc-program") still use PATH as before.
This also includes a commit to centralize the rustc-wrapper program used by several tests so that it isn't built multiple times (and to allow several tests to work on windows).
Fixes#8202
This attempts to centralize all the edition stuff in one place (the
`Edition` enum) so that adding a new edition or stabilizing one should
be relatively little work (and more importantly, we don't miss things).
Importantly, this changes `cargo new` to default to the latest stable.
It also changes the `cargo fix --edition-idiom` behavior to only apply
idioms for the *current* edition.
* `--edition` always means "next" edition.
* `--edition` when on the most recent edition is not an error, just a warning.
* Support fix to 2021 edition.
