Similar to `let_underscore_drop`, this lint checks for statements similar
to `let _ = foo`, where `foo` is a lock guard. These types of let
statements are especially problematic because the lock gets released
immediately, instead of at the end of the scope. This behavior is almost
always the wrong thing.
This lint checks for statements similar to `let _ = foo`, where `foo` is
a type that implements `Drop`. These types of let statements cause the
expression in them to be dropped immediately, instead of at the end of
the scope. Such behavior can be surprizing, especially if you are
relying on the value to be dropped at the end of the scope. Instead, the
binding should be an underscore prefixed name (like `_unused`) or the
value should explicitly be passed to `std::mem::drop()` if the value
really should be dropped immediately.
Cache more queries on disk
One of the principles of incremental compilation is to allow saving results on disk to avoid recomputing them.
This PR investigates persisting a lot of queries whose result are to be saved into metadata.
Some of the queries are cheap reads from HIR, but we may also want to get rid of these reads for incremental lowering.
Do not emit the lint `unused_attributes` for *inherent* `#[doc(hidden)]` associated items
Fixes#97205 (embarrassing oversight from #96008).
`@rustbot` label A-lint
Rollup of 6 pull requests
Successful merges:
- #96565 (rustdoc: show implementations on `#[fundamental]` wrappers)
- #97179 (Add new lint to enforce whitespace after keywords)
- #97185 (interpret/validity: separately control checking numbers for being init and non-ptr)
- #97188 (Remove unneeded null pointer asserts in ptr2int casts)
- #97189 (Update .mailmap)
- #97192 (Say "last" instead of "rightmost" in the documentation for `std::str:rfind`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Remove unneeded null pointer asserts in ptr2int casts
This removes an assert that a pointer with address 0 has no provenance. This change is needed to support permissive provenance work in Miri, and seems justified by `ptr.with_addr(0)` working and a discussion on Zulip regarding LLVM semantics.
r? `@RalfJung`
interpret/validity: separately control checking numbers for being init and non-ptr
This lets Miri control this in a more fine-grained way.
r? `@oli-obk`
generator_interior: Count match pattern bindings as borrowed for the whole guard expression
The test case `yielding-in-match-guard.rs` was failing with `-Zdrop-tracking` enabled. The reason is that the copy of a local (`y`) was not counted as a borrow in typeck, while MIR did consider this as borrowed.
The correct thing to do here is to count pattern bindings are borrowed for the whole guard. Instead, what we were doing is to record the type at the use site of the variable and check if the variable comes from a borrowed pattern. Due to the fix for #57017, we were considering too small of a scope for this variable, which meant it was not counted as borrowed.
Because we now unconditionally record the borrow, rather than only for bindings that are used, this PR is also able to remove a lot of the logic around match bindings that was there before.
r? `@nikomatsakis`
move processing of `source_scope_data` into `MutVisitor`'s impl of `Integrator` when inline
This PR fixes the FIXME in the inline mir-opt which moves processing of `source_scope_data` into `MutVisitor`'s impl of `Integrator` when inline
`simplify_type` improvements and cursed docs
the existing `TreatParams` enum pretty much mixes everything up. Not sure why this looked right to me in #94057
This also includes two changes which impact perf:
- `ty::Projection` with inference vars shouldn't be treated as a rigid type, even if fully normalized
- `ty::Placeholder` only unifies with itself, so actually return `Some` for them
r? `@nikomatsakis`
Permit `asm_const` and `asm_sym` to reference generic params
Related #96557
These constructs will be allowed:
```rust
fn foofoo<const N: usize>() {}
unsafe fn foo<const N: usize>() {
asm!("/* {0} */", const N);
asm!("/* {0} */", const N + 1);
asm!("/* {0} */", sym foofoo::<N>);
}
fn barbar<T>() {}
unsafe fn bar<T>() {
asm!("/* {0} */", const std::mem::size_of::<T>());
asm!("/* {0} */", const std::mem::size_of::<(T, T)>());
asm!("/* {0} */", sym barbar::<T>);
asm!("/* {0} */", sym barbar::<(T, T)>);
}
```
`@Amanieu,` I didn't switch inline asms to use `DefKind::InlineAsm`, as I see little value doing that; given that no type inference is needed, it will only make typecking slower and more complex but will have no real gains. I did switch them to follow the same code path as inline asm during symbol resolution, though.
The `error: unconstrained generic constant` you mentioned in #76001 is due to the fact that `to_const` will actually add a wfness obligation to the constant, which we don't need for `asm_const`, so I have that removed.
`@rustbot` label: +A-inline-assembly +F-asm
--remap-path-prefix: Fix duplicated path components in debuginfo
This PR fixes an issue with `--remap-path-prefix` where path components could appear twice in the remapped version of the path (e.g. https://github.com/rust-lang/rust/issues/78479). The underlying problem was that `--remap-path-prefix` is often used to map an absolute path to something that looks like a relative path, e.g.:
```
--remap-path-prefix=/home/calvin/.cargo/registry/src/github.com-1ecc6299db9ec823=crates.io",
```
and relative paths in debuginfo are interpreted as being relative to the compilation directory. So if Cargo invokes the compiler with `/home/calvin/.cargo/registry/src/github.com-1ecc6299db9ec823/some_crate-0.1.0/src/lib.rs` as input and `/home/calvin/.cargo/registry/src/github.com-1ecc6299db9ec823/some_crate-0.1.0` as the compiler's working directory, then debuginfo will state that the working directory was `crates.io/some_crate-0.1.0` and the file is question was `crates.io/some_crate-0.1.0/src/lib.rs`, which combined gives the path:
```
crates.io/some_crate-0.1.0/crates.io/some_crate-0.1.0/src/lib.rs
```
With this PR the compiler will detect this situation and set up debuginfo in LLVM in a way that makes it strip the duplicated path components when emitting DWARF.
The PR also extracts the logic for making remapped paths absolute into a common helper function that is now used by debuginfo too (instead of just during crate metadata generation).
Clean fix for #96223
Okay, so here we are (hopefully) 👍Closes#96223
Thanks a lot to `@jackh726` for your help and explanation 🙏
- Modified `InferCtxt::mk_trait_obligation_with_new_self_ty` to take as argument a `Binder<(TraitPredicate, Ty)>` instead of a `Binder<TraitPredicate>` and a separate `Ty` with no bound vars.
- Modified all call places to avoid calling `Binder::no_bounds_var` or `Binder::skip_binder` when it is not safe.
r? `@jackh726`
Mention traits and types involved in unstable trait upcasting
Fixes#95972 by printing the traits being upcasted and the types being coerced that cause that upcasting...
---
the poor span mentioned in the original issue has nothing to do with trait upcasting diagnostic here...
> The original example I had that made me run into this issue had an even longer expression there (multiple chained
iterator methods) which just got all highlighted as one big block saying "somewhere here trait coercion is used and it's not allowed".
I don't think I can solve that issue in general without fixing the ObligationCauseCode and span that gets passed into Coerce.
