Rollup of 8 pull requests
Successful merges:
- #135549 (Document some safety constraints and use more safe wrappers)
- #135965 (In "specify type" suggestion, skip type params that are already known)
- #136193 (Implement pattern type ffi checks)
- #136646 (Add a TyPat in the AST to reuse the generic arg lowering logic)
- #136874 (Change the issue number for `likely_unlikely` and `cold_path`)
- #136884 (Lower fn items as ZST valtrees and delay a bug)
- #136885 (i686-linux-android: increase CPU baseline to Pentium 4 (without an actual change)
- #136891 (Check sig for errors before checking for unconstrained anonymous lifetime)
r? `@ghost`
`@rustbot` modify labels: rollup
i686-linux-android: increase CPU baseline to Pentium 4 (without an actual change
As per ``@maurer's`` [comment](https://github.com/rust-lang/rust/issues/136495#issuecomment-2648743078), this shouldn't actually change anything since we anyway add a bunch of extensions that bump things up way beyond Pentium 4. But Pentium 4 is consistent with the other i686 targets and I don't know enough about the exact sequence of CPU generations to be confident with more than this. ;)
Lower fn items as ZST valtrees and delay a bug
Lower it as a ZST instead of a const error, which we can handle mostly fine. Delay a bug so we don't accidentally support it tho.
r? BoxyUwU
Fixes#136855Fixes#136853Fixes#136854Fixes#136337
Only added one test bc that's really the crux of the issue (fn item in array length position).
Add a TyPat in the AST to reuse the generic arg lowering logic
This simplifies ast lowering significantly with little cost to the pattern types parser.
Also fixes any problems we've had with generic args (well, pushes any problems onto the `generic_const_exprs` feature gate)
follow-up to https://github.com/rust-lang/rust/pull/136284#discussion_r1939292367
r? ``@BoxyUwU``
Implement pattern type ffi checks
Previously we just rejected pattern types outright in FFI, but that was never meant to be a permanent situation. We'll need them supported to use them as the building block for `NonZero` and `NonNull` after all (both of which are FFI safe).
best reviewed commit by commit.
In "specify type" suggestion, skip type params that are already known
When we suggest specifying a type for an expression or pattern, like in a `let` binding, we previously would print the entire type as the type system knew it. We now look at the params that have *no* inference variables, so they are fully known to the type system which means that they don't need to be specified.
This helps in suggestions for types that are really long, because we can usually skip most of the type params and make the annotation as short as possible:
```
error[E0282]: type annotations needed for `Result<_, ((..., ..., ..., ...), ..., ..., ...)>`
--> $DIR/really-long-type-in-let-binding-without-sufficient-type-info.rs:7:9
|
LL | let y = Err(x);
| ^ ------ type must be known at this point
|
help: consider giving `y` an explicit type, where the type for type parameter `T` is specified
|
LL | let y: Result<T, _> = Err(x);
| ++++++++++++++
```
Fix#135919.
Document some safety constraints and use more safe wrappers
Lots of unsafe codegen_llvm code has safe wrappers already, so I used some of them and added some where applicable. I stopped here because this diff is large enough and should probably be reviewed independently of other changes.
Properly deeply normalize in the next solver
Turn deep normalization into a `TypeOp`. In the old solver, just dispatch to the `Normalize` type op, but in the new solver call `deeply_normalize`. I chose to separate it into a different type op b/c some normalization is a no-op in the new solver, so this distinguishes just the normalization we need for correctness.
Then use `DeeplyNormalize` in the callsites we used to be using a `CustomTypeOp` (for normalizing known type outlives obligations), and also use it to normalize function args and impl headers in the new solver.
Finally, use it to normalize signatures for WF checks in the new solver as well. This addresses https://github.com/rust-lang/trait-system-refactor-initiative/issues/146.
Simplify intra-crate qualifiers.
The following is a weird pattern for a file within `rustc_middle`:
```
use rustc_middle::aaa;
use crate::bbb;
```
More sensible and standard would be this:
```
use crate::{aaa, bbb};
```
I.e. we generally prefer using `crate::` to using a crate's own name. (Exceptions are things like in macros where `crate::` doesn't work because the macro is used in multiple crates.)
This commit fixes a bunch of these weird qualifiers.
r? `@jieyouxu`
compiler: die immediately instead of handling unknown target codegen
We cannot produce anything useful if asked to compile unknown targets. We should handle the error immediately at the point of discovery instead of propagating it upward, and preferably in the simplest way: Die.
This allows cleaning up our "error-handling" spread across 5 crates.
show supported register classes in error message
a simple diagnostic change that shows the supported register classes when an invalid one is found.
This information can be hard to find (especially for unstable targets), and this message now gives at least something to try or search for. I've followed the pattern for invalid clobber ABIs.
`@rustbot` label +A-inline-assembly
fix ensure_monomorphic_enough
When polymorphization was still a thing, the visitor was used to only recurse into *used generic parameters* of function/closure/coroutine types and allow unused parameters (i.e. the polymorphized parameters) to remain generic.
When polymorphization got removed, this got changed to always treat all parameters as polymorphic and never recurse into them: https://github.com/rust-lang/rust/pull/133883/files#diff-210c59e321070d0ca4625c04e9fb064bf43ddc34082e7e33a7ee8a6c577e95afL44-L62
This is clearly wrong and can cause MIR opts to misbehave, for example this currently prints "false" in release mode:
```rust
#![feature(core_intrinsics)]
fn generic<T>() {}
const fn type_id_of_val<T: 'static>(_: &T) -> u128 {
std::intrinsics::type_id::<T>()
}
fn cursed_is_i32<T: 'static>() -> bool {
(const { type_id_of_val(&generic::<T>) } == const { type_id_of_val(&generic::<i32>) })
}
fn main() {
dbg!(cursed_is_i32::<i32>());
}
```
This PR reverts to the old behavior of always treating all types that contain type parameters as too generic, like we used to do without `-Zpolymorphize` before.
~~I'm not including the above as a test case here, because I think there is little value in testing code paths that have been removed and this seems unlikely to regress in a way that would be caught by a regression test, but let me know if you disagree and want me to add a test anyway.~~
Overhaul how contracts are lowered on fn-like bodies
Consolidates all of the contracts lowering logic into `lower_fn_body`, rather than having it be split between `lower_item_kind` and `lower_fn_body`. This should fix#136683.
r? celinval
Stop using span hack for contracts feature gating
The contracts machinery is a pretty straightforward case of an *external* feature using a (perma-unstable) *internal* feature within its implementation. There's no reason why it needs to be implemented any differently than other features by using global span tracking hacks to change whether the internals are gated behind the `contracts` or `contracts_internals` feature gate -- for the case of macro expansions we already have `allow_internal_unstable` for exactly this situation.
This PR changes the internal, perma-unstable AST syntax to use the `contracts_internals` gate always, and adjusts the macro expansion to use the right spans so that `allow_internal_unstable` works correctly.
As a follow-up, there's really no reason to have `contracts` be a *compiler feature* since it's at this point fully a *library feature*; the only reason it's a compiler feature today is so we can mark it as incomplete, but that seems like a weak reason. I didn't do anything in this PR for this.
r? ``@celinval``
cg_llvm: Reduce visibility of some items outside the `llvm` module
Next piece of #135502
This reduces the visibility of items (other than those in the `llvm` module) so that dead code analysis will correctly identify unused items.
The following is a weird pattern for a file within `rustc_middle`:
```
use rustc_middle::aaa;
use crate::bbb;
```
More sensible and standard would be this:
```
use crate::{aaa, bbb};
```
I.e. we generally prefer using `crate::` to using a crate's own name.
(Exceptions are things like in macros where `crate::` doesn't work
because the macro is used in multiple crates.)
This commit fixes a bunch of these weird qualifiers.
Show diff suggestion format on verbose replacement
```
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;
|
```
before:
```
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 _ = 2.0f64;
| ~~~~
```
r? `@oli-obk`
compiler: gate `extern "{abi}"` in ast_lowering
I don't believe low-level crates like `rustc_abi` should have to know or care about higher-level concerns like whether the ABI string is stable for users. These implementation details can be made less open to public inspection. This way the code that governs stability is near the code that enforces stability, and compiled together.
It also abstracts away certain error messages instead of constantly repeating them.
A few error messages are simply deleted outright, instead of made uniform, because they are either too dated to be useful or redundant with other diagnostic improvements we could make. These can be pursued in followups: my first concern was making sure there wasn't unnecessary diagnostics-related code in `rustc_abi`, which is not well-positioned to understand what kind of errors are going to be generated based on how it is used.
r? ``@ghost``
Prevent generic pattern types from being used in libstd
Pattern types should follow the same rules that patterns follow. So a pattern type range must not wrap and not be empty. While we reject such invalid ranges at layout computation time, that only happens during monomorphization in the case of const generics. This is the exact same issue as other const generic math has, and since there's no solution there yet, I put these pattern types behind a separate incomplete feature.
These are not necessary for the pattern types MVP (replacing the layout range attributes in libcore and rustc).
cc #136574 (new tracking issue for the `generic_pattern_types` feature gate)
r? ``@lcnr``
cc ``@scottmcm`` ``@joshtriplett``
Delay bug when method confirmation cannot upcast object pick of self
Justification is on the test comment. Simply delays a bug that we were previously ICEing on.
cc ``@adetaylor`` since this is a `arbitrary_self_types` ICE.
Introduce CoercePointeeWellformed for coherence checks at typeck stage
Fix#135206
This is the first PR to introduce the "wellformedness" check for `derive(CoercePointee)`.
This patch introduces a new error code to cover all the prerequisites of the said macro. The checks that is enforced with this patch is whether the data is indeed `struct` and whether the layout is set to `repr(transparent)`.
A following series of patch will arrive later to address the following concern.
1. #135217 so that we would only admit one single coercion on one type parameter, and leave the rest for future consideration in tandem of development of other coercion rules.
1. Enforcement of data field requirements.
**An open question** is whether there is a good schema to encode the `#[pointee]` as well, so that we could also check if the `#[pointee]` type parameter is indeed `?Sized`.
``@rustbot`` label F-derive_coerce_pointee
```
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;
|
```
