make trait-aliases work across crates
This is rebase of a small part of @alexreg's PR #55994. It focuses just on the changes that integrate trait aliases properly into crate metadata, excluding the stylistic edits and the trait objects.
The stylistic edits I also rebased and can open a separate PR.
The trait object stuff I found challenging and decided it basically needed to be reimplemented. For now I've excluded it.
Since this is really @alexreg's work (I really just rebased) I am going to make it r=me once it is working.
Fixes#56488.
Fixes#57023.
Generalize `huge-enum.rs` test and expected stderr for more cross platform cases
With this change, I am able to build and test cross-platform `rustc`
In particular, I can use the following in my `config.toml`:
```
[build]
host = ["i686-unknown-linux-gnu", "x86_64-unknown-linux-gnu"]
target = ["i686-unknown-linux-gnu", "x86_64-unknown-linux-gnu"]
```
Before this change, my attempt to run the test suite would fail
because the error output differs depending on what your host and
targets are.
----
To be concrete, here are the actual messages one can observe:
```
% ./build/x86_64-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=x86_64-unknown-linux-gnu
error: the type `std::option::Option<[u32; 35184372088831]>` is too big for the current architecture
error: aborting due to previous error
% ./build/x86_64-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=i686-unknown-linux-gnu
error: the type `std::option::Option<[u32; 536870911]>` is too big for the current architecture
error: aborting due to previous error
% ./build/i686-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=i686-unknown-linux-gnu
error: the type `std::option::Option<[u32; 536870911]>` is too big for the current architecture
error: aborting due to previous error
% ./build/i686-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=x86_64-unknown-linux-gnu
error: the type `[u32; 35184372088831]` is too big for the current architecture
error: aborting due to previous error
```
To address these variations, I changed the test to be more aggressive
in its normalization strategy. We cannot (and IMO should not)
guarantee that `Option` will appear in the error output here. So I
normalized both types `Option<[u32; N]>` and `[u32; N]` to just `TYPE`
High priority resolutions for associated variants
In https://github.com/rust-lang/rust/pull/56225 variants were assigned lowest priority during name resolution to avoid crater run and potential breakage.
This PR changes the rules to give variants highest priority instead.
Some motivation:
- If variants (and their constructors) are treated as associated items, then they are obviously *inherent* associated items since they don't come from traits.
- Inherent associated items have higher priority during resolution than associated items from traits.
- The reason is that there is a way to disambiguate in favor of trait items (`<Type as Trait>::Ambiguous`), but there's no way to disambiguate in favor of inherent items, so they became unusable in case of ambiguities if they have low priority.
- It's technically problematic to fallback from associated types to anything until lazy normalization (?) is implemented.
Crater found some regressions from this change, but they are all in type positions, e.g.
```rust
fn f() -> Self::Ambiguos { ... } // Variant `Ambiguous` or associated type `Ambiguous`?
```
, so variants are not usable there right now, but they may become usable in the future if https://github.com/rust-lang/rfcs/pull/2593 is accepted.
This PR keeps code like this successfully resolving, but introduces a future-compatibility lint `ambiguous_associated_items` that recommends rewriting it as `<Self as Trait>::Ambiguous`.
Fix stack overflow when finding blanket impls
Currently, SelectionContext tries to prevent stack overflow by keeping
track of the current recursion depth. However, this depth tracking is
only used when performing normal section (which includes confirmation).
No such tracking is performed for evaluate_obligation_recursively, which
can allow a stack overflow to occur.
To fix this, this commit tracks the current predicate evaluation depth.
This is done separately from the existing obligation depth tracking:
an obligation overflow can occur across multiple calls to 'select' (e.g.
when fulfilling a trait), while a predicate evaluation overflow can only
happen as a result of a deep recursive call stack.
Fixes#56701
I've re-used `tcx.sess.recursion_limit` when checking for predication evaluation overflows. This is such a weird corner case that I don't believe it's necessary to have a separate setting controlling the maximum depth.
Fix suggestions given mulitple bad lifetimes
When given multiple lifetimes prior to type parameters in generic
parameters, do not ICE and print the correct suggestion.
r? @estebank
CC @pnkfelix
Fixes: #57521
librustc_metadata: Pass a default value when unwrapping a span
Fixes#57323.
When compiling with `static-nobundle` a-la
`rustc -l static-nobundle=nonexistent main.rs`
we now get a neat output in the form of:
```
error[E0658]: kind="static-nobundle" is feature gated (see issue #37403)
|
= help: add #![feature(static_nobundle)] to the crate attributes to enable
error: aborting due to previous error
For more information about this error, try `rustc --explain E0658`.
```
The build and tests completed successfully on my machine. Should I be adding a new test?
Better error note on unimplemented Index trait for string
fixes#56740
I've tried to compile suggestion from comments in the issue #56740, but unsure of it. So I'm open to advice :)
Current output will be like this:
```rust
error[E0277]: the type `str` cannot be indexed by `{integer}`
--> $DIR/str-idx.rs:3:17
|
LL | let c: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
| ^^^^ `str` cannot be indexed by `{integer}`
|
= help: the trait `std::ops::Index<{integer}>` is not implemented for `str`
= note: you can use `.chars().nth()` or `.bytes().nth()`
see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.
```
`x.py test src/test/ui` succeeded and I've also tested output manually by compiling the following code:
```rust
fn _f() {
let s = std::string::String::from("hello");
let _c = s[0];
let s = std::string::String::from("hello");
let mut _c = s[0];
let s = "hello";
let _c = s[0];
let s = "hello";
let mut _c = &s[0];
}
```
Not sure if some docs should be changed too. I will also fix error message in the [Book :: Indexing into Strings](db53e2e3cd/src/ch08-02-strings.md (indexing-into-strings)) if that PR will get approved :)
Additionally, the root implementation was changed a bit: it now uses
`all` instead of coding that logic manually.
To avoid duplicate code, the inherent `[T]::is_sorted_by` method now
calls `self.iter().is_sorted_by(...)`. This should always be inlined
and not result in overhead.
Multiple people have asked for them, in
https://github.com/rust-lang/rust/issues/49137.
Given that the unsigned ones already exist,
they are very easy to add and not an additional maintenance burden.
Implement basic input validation for built-in attributes
Correct top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is enforced for built-in attributes, built-in attributes must also fit into the "meta-item" syntax (aka the "classic attribute syntax").
For some subset of attributes (found by crater run), errors are lowered to deprecation warnings.
NOTE: This PR previously included https://github.com/rust-lang/rust/pull/57367 as well.
In particular, I can use the following in my `config.toml`:
```
[build]
host = ["i686-unknown-linux-gnu", "x86_64-unknown-linux-gnu"]
target = ["i686-unknown-linux-gnu", "x86_64-unknown-linux-gnu"]
```
Before this change, my attempt to run the test suite would fail
because the error output differs depending on what your host and
targets are.
----
To be concrete, here are the actual messages one can observe:
```
% ./build/x86_64-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=x86_64-unknown-linux-gnu
error: the type `std::option::Option<[u32; 35184372088831]>` is too big for the current architecture
error: aborting due to previous error
% ./build/x86_64-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=i686-unknown-linux-gnu
error: the type `std::option::Option<[u32; 536870911]>` is too big for the current architecture
error: aborting due to previous error
% ./build/i686-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=i686-unknown-linux-gnu
error: the type `std::option::Option<[u32; 536870911]>` is too big for the current architecture
error: aborting due to previous error
% ./build/i686-unknown-linux-gnu/stage1/bin/rustc ../src/test/ui/huge-enum.rs -Aunused --target=x86_64-unknown-linux-gnu
error: the type `[u32; 35184372088831]` is too big for the current architecture
error: aborting due to previous error
```
To address these variations, I changed the test to be more aggressive
in its normalization strategy. We cannot (and IMO should not)
guarantee that `Option` will appear in the error output here. So I
normalized both types `Option<[u32; N]>` and `[u32; N]` to just `TYPE`
rustc: Remove platform intrinsics crate
This was originally attempted in #57048 but it was realized that we
could fully remove the crate via the `"unadjusted"` ABI on intrinsics.
This means that all intrinsics in stdsimd are implemented directly
against LLVM rather than using the abstraction layer provided here. That
ends up meaning that this crate is no longer used at all.
This crate developed long ago to implement the SIMD intrinsics, but we
didn't end up using it in the long run. In that case let's remove it!
forbid manually impl'ing one of an object type's marker traits
This shouldn't break compatibility for crates that do not use
`feature(optin_builtin_traits)`, because as the test shows, it is
only possible to impl a marker trait for a trait object in the crate the
marker trait is defined in, which must define
`feature(optin_builtin_traits)`.
Fixes#56934.
r? @nikomatsakis
Modify some parser diagnostics to continue evaluating beyond the parser
Continue evaluating further errors after parser errors on:
- trailing type argument attribute
- lifetime in incorrect location
- incorrect binary literal
- missing `for` in `impl Trait for Foo`
- type argument in `where` clause
- incorrect float literal
- incorrect `..` in pattern
- associated types
- incorrect discriminator value variant error
and others. All of these were found by making `continue-parse-after-error` `true` by default to identify errors that would need few changes. There are now only a handful of errors that have any change with `continue-parse-after-error` enabled.
These changes make it so `rust` _won't_ stop evaluation after finishing parsing, enabling type checking errors to be displayed on the existing code without having to fix the parse errors.
Each commit has an individual diagnostic change with their corresponding tests.
CC #48724.
This was originally attempted in #57048 but it was realized that we
could fully remove the crate via the `"unadjusted"` ABI on intrinsics.
This means that all intrinsics in stdsimd are implemented directly
against LLVM rather than using the abstraction layer provided here. That
ends up meaning that this crate is no longer used at all.
This crate developed long ago to implement the SIMD intrinsics, but we
didn't end up using it in the long run. In that case let's remove it!
Stabilize cfg_target_vendor
This stabilizes the use of `cfg(target_vendor = "...")` and removes the corresponding `cfg_target_vendor` feature. Other unstable cfgs remain behind their existing feature gates.
This functionality was added back in 2015 in #28612 to complete the coverage of target tuples (`<arch><sub>-<vendor>-<os>-<env>`). [RFC 131](https://github.com/rust-lang/rfcs/blob/master/text/0131-target-specification.md) governs the target specification, not including `target_vendor` seems to have just been an oversight. `target_os`, `target_family`, and `target_arch` are stable as of 1.0.0. `target_env` was also not mentioned in RFC 131, was added in #24777, never behind a feature_gate, and insta-stable at 1.1.0.
The functionality is tested in [test/run-pass/cfg/cfg-target-vendor.rs](https://github.com/rust-lang/rust/blob/master/src/test/run-pass/cfg/cfg-target-vendor.rs).
Closes#29718
Stabilize core::convert::identity
r? @SimonSapin
fixes https://github.com/rust-lang/rust/issues/53500
This is waiting for FCP to complete but in the interim it would be good to review.
Use structured suggestions for nonstandard style lints
This PR modifies the lints in the nonstandard_style group to use structured suggestions. Note that there's a bit of tricky span calculation going on for the `crate_name` attribute. It also simplifies the code a bit: I don't think the "fallback" suggestions for these lints can actually be triggered.
Fixes#48103.
Fixes#52414.
Rollup of 4 pull requests
Successful merges:
- #56874 (Simplify foreign type rendering.)
- #57113 (Move diagnostics out from QueryJob and optimize for the case with no diagnostics)
- #57366 (Point at match discriminant on type error in match arm pattern)
- #57538 (librustc_mir: Fix ICE with slice patterns)
Failed merges:
- #57381 (Tweak output of type mismatch between "then" and `else` `if` arms)
r? @ghost
librustc_mir: Fix ICE with slice patterns
If a match arm does not include all fields in a structure and a later
pattern includes a field that is an array, we will attempt to use the
array type from the prior arm. When calculating the field type, treat
a array of an unknown size as a `TyErr`.
Fixes: #57472
Point at match discriminant on type error in match arm pattern
```
error[E0308]: mismatched types
--> src/main.rs:5:9
|
4 | let temp: usize = match a + b {
| ----- this expression has type `usize`
5 | Ok(num) => num,
| ^^^^^^^ expected usize, found enum `std::result::Result`
|
= note: expected type `usize`
found type `std::result::Result<_, _>`
```
Fix#57279.
This shouldn't break compatibility for crates that do not use
`feature(optin_builtin_traits)`, because as the test shows, it is
only possible to impl a marker trait for a trait object in the crate the
marker trait is defined in, which must define
`feature(optin_builtin_traits)`.
Fixes#56934
NLL: Add union justifications to conflicting borrows.
Fixes#57100.
This PR adds justifications to error messages for conflicting borrows of union fields.
Where previously an error message would say ``cannot borrow `u.b` as mutable..``, it now says ``cannot borrow `u` (via `u.b`) as mutable..``.
r? @pnkfelix
If a match arm does not include all fields in a structure and a later
pattern includes a field that is an array, we will attempt to use the
array type from the prior arm. When calculating the field type, treat
a array of an unknown size as a TyErr.
Update the const fn tracking issue to the new metabug
The new `const fn` tracking issue is #57563. We don't want to point to a closed issue in the diagnostics (or FIXMEs), so these have been updated (from the old issue, #24111).
r? @Centril
...while still keeping ambiguity errors future-proofing for uniform paths.
This corner case is not going to be stabilized for 1.32 and needs some more general experiments about retrofitting 2018 import rules to 2015 edition
Rollup of 26 pull requests
Successful merges:
- #56425 (Redo the docs for Vec::set_len)
- #56906 (Issue #56905)
- #57042 (Don't call `FieldPlacement::count` when count is too large)
- #57175 (Stabilize `let` bindings and destructuring in constants and const fn)
- #57192 (Change std::error::Error trait documentation to talk about `source` instead of `cause`)
- #57296 (Fixed the link to the ? operator)
- #57368 (Use CMAKE_{C,CXX}_COMPILER_LAUNCHER for ccache)
- #57400 (Rustdoc: update Source Serif Pro and replace Heuristica italic)
- #57417 (rustdoc: use text-based doctest parsing if a macro is wrapping main)
- #57433 (Add link destination for `read-ownership`)
- #57434 (Remove `CrateNum::Invalid`.)
- #57441 (Supporting backtrace for x86_64-fortanix-unknown-sgx.)
- #57450 (actually take a slice in this example)
- #57459 (Reference tracking issue for inherent associated types in diagnostic)
- #57463 (docs: Fix some 'second-edition' links)
- #57466 (Remove outdated comment)
- #57493 (use structured suggestion when casting a reference)
- #57498 (make note of one more normalization that Paths do)
- #57499 (note that FromStr does not work for borrowed types)
- #57505 (Remove submodule step from README)
- #57510 (Add a profiles section to the manifest)
- #57511 (Fix undefined behavior)
- #57519 (Correct RELEASES.md for 1.32.0)
- #57522 (don't unwrap unexpected tokens in `format!`)
- #57530 (Fixing a typographical error.)
- #57535 (Stabilise irrefutable if-let and while-let patterns)
Failed merges:
r? @ghost
Reference tracking issue for inherent associated types in diagnostic
This makes it clearer that associated types in inherent impls are an intended feature, like the diagnostic for equality constraints in where clauses. (This is more helpful, because the lack of associated types is a confusing omission and it lets users more easily track the state of the feature.)
Stabilize `let` bindings and destructuring in constants and const fn
r? @Centril
This PR stabilizes the following features in constants and `const` functions:
* irrefutable destructuring patterns (e.g. `const fn foo((x, y): (u8, u8)) { ... }`)
* `let` bindings (e.g. `let x = 1;`)
* mutable `let` bindings (e.g. `let mut x = 1;`)
* assignment (e.g. `x = y`) and assignment operator (e.g. `x += y`) expressions, even where the assignment target is a projection (e.g. a struct field or index operation like `x[3] = 42`)
* expression statements (e.g. `3;`)
This PR does explicitly *not* stabilize:
* mutable references (i.e. `&mut T`)
* dereferencing mutable references
* refutable patterns (e.g. `Some(x)`)
* operations on `UnsafeCell` types (as that would need raw pointers and mutable references and such, not because it is explicitly forbidden. We can't explicitly forbid it as such values are OK as long as they aren't mutated.)
* We are not stabilizing `let` bindings in constants that use `&&` and `||` short circuiting operations. These are treated as `&` and `|` inside `const` and `static` items right now. If we stopped treating them as `&` and `|` after stabilizing `let` bindings, we'd break code like `let mut x = false; false && { x = true; false };`. So to use `let` bindings in constants you need to change `&&` and `||` to `&` and `|` respectively.
NLL: Fix bug in associated constant type annotations.
Fixes#57280.
This PR reverses the variance used when relating types from the type
annotation of an associated constant - this matches the behaviour of the
lexical borrow checker and fixes a bug whereby matching a `&'a str`
against a `&'static str` would produce an error.
r? @nikomatsakis
tests: Do not use `-Z parse-only`, continue compilation to test recovery
Make tests closer to reality!
The next step will be enabling `-Z continue-parse-after-error` by default and looking at the regressions.
A few instances of `-Z parse-only` are kept when it's appropriate, see e.g `ui/impl-trait/impl-trait-plus-priority.rs`, which tests mostly semantically wrong code and would generate too much useless noise if allowed to continue.
Make sure feature gate errors are recoverable (take 2)
Continuation of 15cefe4b2a.
Turns out I missed the most important part - the main feature gate checking pass.
use structured suggestion for method calls
Furthermore, don't suggest calling the method if it is part of a place
expression, as this is invalid syntax.
I'm thinking it might be worth putting a label on the method assignment span like "this is a method" and removing the span from the "methods are immutable" text so it isn't reported twice.
The suggestions in `src/test/ui/did_you_mean/issue-40396.stderr` are suboptimal. I could check if the containing expression is `BinOp`, but I'm not sure if that's general enough. Any ideas?
r? @estebank
Fix#56806 by using `delay_span_bug` in object safety layout sanity checks
It's possible that `is_object_safe` is called on a trait method that with an invalid receiver type. This caused an ICE in #56806, because `receiver_is_dispatchable` returns `true` for `self: Box<dyn Trait>`, which causes one of the layout sanity checks in object_safety.rs to fail. Replacing `bug!` with `delay_span_bug` solves this.
The fact that `receiver_is_dispatchable` returns `true` here could be considered a bug. It passes the check that the method implements, though: `Box<dyn Trait>` implements `DispatchFromDyn<Box<dyn Trait>>` because `dyn Trait` implements `Unsize<dyn Trait>`. It would be good to hear what @eddyb and @nikomatsakis think.
Note that I only added a test for the case encountered in #56806. I could not come up with a case that triggered an ICE from the other check, `bug!("receiver when Self = dyn Trait should be ScalarPair, found Scalar")`. There is no way, to my knowledge, that you can make `receiver_is_dispatchable` return true but still have a `Scalar` ABI when `Self = dyn Trait`.
One other case I encountered while debugging #56806 was that if you have a type parameter `T` that implements `Deref<Target=Self>` and `DispatchFromDyn<T>`, and use it as a method receiver, it will cause an ICE during `is_object_safe` because `T` has no layout ([playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=d9b7497b3be0ca8382fa7d9497263214)):
```rust
trait Trait<T: Deref<Target=Self> + DispatchFromDyn<T>> {
fn foo(self: T) -> dyn Trait<T>;
}
```
I don't intend to remove the ICE there because it is a pathological case, especially since there is no way to implement `DispatchFromDyn<T>` for `T` — the checks in typeck/coherence/builtin.rs do not allow that.
fixes#56806
r? @varkor
NLL: Add closure cannot be moved note.
Fixes#57098.
This PR extends existing logic for checking whether a closure that
is `FnOnce` and therefore moves variables that it captures from the
environment has already been invoked when being invoked again.
Now, this logic will also check whether the closure is being moved after
previously being moved or invoked and add an appropriate note.
r? @pnkfelix
Add support for trait-objects without a principal
The hard-error version of #56481 - should be merged after we do something about the `traitobject` crate.
Fixes#33140.
Fixes#57057.
r? @nikomatsakis
Implement the Re-rebalance coherence RFC
This is the first time I touch anything in the compiler so just tell me if I got something wrong.
Big thanks to @sgrif for the pointers where to look for those things.
cc #55437
It's possible that `is_object_safe` is called on a trait that is ill-formed, and we shouldn't ICE unless there are no errors being raised. Using `delay_span_bug` solves this.
fixes#56806
This commit improves the logic for place descriptions in conflicting
borrow errors so that borrows of union fields have better messages even
when the unions are embedded in other unions or structs.
make `panictry!` private to libsyntax
This commit completely removes usage of the `panictry!` macro from
outside libsyntax. The macro causes parse errors to be fatal, so using
it in libsyntax_ext caused parse failures *within* a syntax extension to
be fatal, which is probably not intended.
Furthermore, this commit adds spans to diagnostics emitted by empty
extensions if they were missing, à la #56491.
This commit reverses the variance used when relating types from the type
annotation of an associated constant - this matches the behaviour of the
lexical borrow checker and fixes a bug whereby matching a `&'a str`
against a `&'static str` would produce an error.
Universes
This PR transitions the compiler to use **universes** instead of the **leak-check**. It is marked as [WIP] for a few reasons:
- The diagnostics at present are terrible =)
- This changes the behavior of coherence, regressing some things that used to compile
The goals of this PR at present are:
- To start getting some eyes on the code
- To do a crater run
- To see the full travis results (due to https://github.com/rust-lang/rust/issues/52452, I am not able to run the full test suite locally anymore at present)
The first few commits in the PR are changing how `evaluate` treats regions. We now track whether region comparisons occurred, reverting the "staticized" query approach that @arielb1 put in. The problem with "staticized" queries is that it relied on the leak-check to get higher-ranked things correct, and we are removing the leak-check in this PR series, so that caused problems.
You can see at the end a collection of test updates. Mostly we behave the same but with atrocious diagnostics, but there are a number of cases where we used to error and now no longer do, as well as single case where we used to **not** error but we now do (the coherence-subtyping change).
(Note: it would be possible to do a version of leak-check that propagates universe information and recover the old behavior. I am reluctant to do so because I'd like to leave us room to get more precise -- e.g., I want to eventually handle things like `exists<'a> { for<'b> { if ('a: 'b) { 'a: 'b } } }` which presently the leak-check cannot cope with etc. Also because it seems more consistent to me: most folks I've talked to expect the new behavior and are surprised to learn that binding sites were so significant before when it comes to coherence. One question is, though, to what extent are people relying on this in the wild?)
