Uplift `clippy::{drop,forget}_{ref,copy}` lints
This PR aims at uplifting the `clippy::drop_ref`, `clippy::drop_copy`, `clippy::forget_ref` and `clippy::forget_copy` lints.
Those lints are/were declared in the correctness category of clippy because they lint on useless and most probably is not what the developer wanted.
## `drop_ref` and `forget_ref`
The `drop_ref` and `forget_ref` lint checks for calls to `std::mem::drop` or `std::mem::forget` with a reference instead of an owned value.
### Example
```rust
let mut lock_guard = mutex.lock();
std::mem::drop(&lock_guard) // Should have been drop(lock_guard), mutex
// still locked
operation_that_requires_mutex_to_be_unlocked();
```
### Explanation
Calling `drop` or `forget` on a reference will only drop the reference itself, which is a no-op. It will not call the `drop` or `forget` method on the underlying referenced value, which is likely what was intended.
## `drop_copy` and `forget_copy`
The `drop_copy` and `forget_copy` lint checks for calls to `std::mem::forget` or `std::mem::drop` with a value that derives the Copy trait.
### Example
```rust
let x: i32 = 42; // i32 implements Copy
std::mem::forget(x) // A copy of x is passed to the function, leaving the
// original unaffected
```
### Explanation
Calling `std::mem::forget` [does nothing for types that implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html) since the value will be copied and moved into the function on invocation.
-----
Followed the instructions for uplift a clippy describe here: https://github.com/rust-lang/rust/pull/99696#pullrequestreview-1134072751
cc `@m-ou-se` (as T-libs-api leader because the uplifting was discussed in a recent meeting)
My type ascription
Oh rip it out
Ah
If you think we live too much then
You can sacrifice diagnostics
Don't mix your garbage
Into my syntax
So many weird hacks keep diagnostics alive
Yet I don't even step outside
So many bad diagnostics keep tyasc alive
Yet tyasc doesn't even bother to survive!
Migrate trivially translatable `rustc_parse` diagnostics
cc #100717
Migrate diagnostics in `rustc_parse` which are emitted in a single statement. I worked on this by expanding the lint introduced in #108760, although that isn't included here as there is much more work to be done to satisfy it
Adds a link to the relevant part of The Rust Reference in the eror
message, and suggests a possible fix (replacing the fragment specifier
with :tt in the macro definition).
Fixes typos in the original message.
Signed-off-by: Lena Milizé <me@lvmn.org>
Migrate most of `rustc_builtin_macros` to diagnostic impls
cc #100717
This is a couple of days work, but I decided to stop for now before the PR becomes too big. There's around 50 unresolved failures when `rustc::untranslatable_diagnostic` is denied, which I'll finish addressing once this PR goes thtough
A couple of outputs have changed, but in all instances I think the changes are an improvement/are more consistent with other diagnostics (although I'm happy to revert any which seem worse)
Add suggestion to remove `derive()` if invoked macro is non-derive
Adds to the existing `expected derive macro, found {}` error message:
```
help: remove the surrounding "derive()":
--> $DIR/macro-path-prelude-fail-4.rs:1:3
|
LL | #[derive(inline)]
| ^^^^^^^ ^
```
This suggestion will either fix the issue, in the case that the macro was valid, or provide a better error message if not
Not ready for merge yet, as the highlighted span is only valid for trivial formatting. Is there a nice way to get the parent span of the macro path within `smart_resolve_macro_path`?
Closes#109589
Rollup of 9 pull requests
Successful merges:
- #104363 (Make `unused_allocation` lint against `Box::new` too)
- #106633 (Stabilize `nonzero_min_max`)
- #106844 (allow negative numeric literals in `concat!`)
- #108071 (Implement goal caching with the new solver)
- #108542 (Force parentheses around `match` expression in binary expression)
- #108690 (Place size limits on query keys and values)
- #108708 (Prevent overflow through Arc::downgrade)
- #108739 (Prevent the `start_bx` basic block in codegen from having two `Builder`s at the same time)
- #108806 (Querify register_tools and post-expansion early lints)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
allow negative numeric literals in `concat!`
Fixes#106837
While *technically* negative numeric literals are implemented as unary operations, users can reasonably expect that negative literals are treated the same as positive literals.
Explain compile-time vs run-time difference in env!() error message
This PR is clarifying error message of `env!()` based on this user question: https://users.rust-lang.org/t/environment-variable-out-dir-is-undefined/90067
It makes it clear that `env!()` is for env variables defined at compile-time. There's special-case help text for common Cargo build script variables.
I've also rearranged the code to avoid allocating error message on the happy path when the env var is defined.
Move format_args!() into AST (and expand it during AST lowering)
Implements https://github.com/rust-lang/compiler-team/issues/541
This moves FormatArgs from rustc_builtin_macros to rustc_ast_lowering. For now, the end result is the same. But this allows for future changes to do smarter things with format_args!(). It also allows Clippy to directly access the ast::FormatArgs, making things a lot easier.
This change turns the format args types into lang items. The builtin macro used to refer to them by their path. After this change, the path is no longer relevant, making it easier to make changes in `core`.
This updates clippy to use the new language items, but this doesn't yet make clippy use the ast::FormatArgs structure that's now available. That should be done after this is merged.
