More precise spans for HIR paths
`Ty::assoc_item` is lowered to `<Ty>::assoc_item` in HIR, but `Ty` got span from the whole path.
This PR fixes that, and adjusts some diagnostic code that relied on `Ty` having the whole path span.
This is a pre-requisite for https://github.com/rust-lang/rust/pull/82868 (we cannot report suggestions like `Tr::assoc` -> `<dyn Tr>::assoc` with the current imprecise spans).
r? ````@estebank````
Allow rustdoc to handle asm! of foreign architectures
This allows rustdoc to process code containing `asm!` for architectures other than the current one. Since this never reaches codegen, we just replace target-specific registers and register classes with a dummy one.
Fixes#82869
Fixes issue #82920
Even if an item does not change between compilation sessions, it may end
up with a different `DefId`, since inserting/deleting an item affects
the `DefId`s of all subsequent items. Therefore, we use a `DefPathHash`
in the incremental compilation system, which is stable in the face of
changes to unrelated items.
In particular, the query system will consider the inputs to a query to
be unchanged if any `DefId`s in the inputs have their `DefPathHash`es
unchanged. Queries are pure functions, so the query result should be
unchanged if the query inputs are unchanged.
Unfortunately, it's possible to inadvertantly make a query result
incorrectly change across compilations, by relying on the specific value
of a `DefId`. Specifically, if the query result is a slice that gets
sorted by `DefId`, the precise order will depend on how the `DefId`s got
assigned in a particular compilation session. If some definitions end up
with different `DefId`s (but the same `DefPathHash`es) in a subsequent
compilation session, we will end up re-computing a *different* value for
the query, even though the query system expects the result to unchanged
due to the unchanged inputs.
It turns out that we have been sorting the predicates computed during
`astconv` by their `DefId`. These predicates make their way into the
`super_predicates_that_define_assoc_type`, which ends up getting used to
compute the vtables of trait objects. This, re-ordering these predicates
between compilation sessions can lead to undefined behavior at runtime -
the query system will re-use code built with a *differently ordered*
vtable, resulting in the wrong method being invoked at runtime.
This PR avoids sorting by `DefId` in `astconv`, fixing the
miscompilation. However, it's possible that other instances of this
issue exist - they could also be easily introduced in the future.
To fully fix this issue, we should
1. Turn on `-Z incremental-verify-ich` by default. This will cause the
compiler to ICE whenver an 'unchanged' query result changes between
compilation sessions, instead of causing a miscompilation.
2. Remove the `Ord` impls for `CrateNum` and `DefId`. This will make it
difficult to introduce ICEs in the first place.
Edition-specific preludes
This changes `{std,core}::prelude` to export edition-specific preludes under `rust_2015`, `rust_2018` and `rust_2021`. (As suggested in https://github.com/rust-lang/rust/issues/51418#issuecomment-395630382.) For now they all just re-export `v1::*`, but this allows us to add things to the 2021edition prelude soon.
This also changes the compiler to make the automatically injected prelude import dependent on the selected edition.
cc `@rust-lang/libs` `@djc`
Add suggestion `.collect()` for iterators in iterators
Closes#81584
```
error[E0515]: cannot return value referencing function parameter `y`
--> main3.rs:4:38
|
4 | ... .map(|y| y.iter().map(|x| x + 1))
| -^^^^^^^^^^^^^^^^^^^^^^
| |
| returns a value referencing data owned by the current function
| `y` is borrowed here
| help: Maybe use `.collect()` to allocate the iterator
```
Added the suggestion: `help: Maybe use `.collect()` to allocate the iterator`
Improve anonymous lifetime note to indicate the target span
Improvement for #81650
Cc #81995
Message after this improvement:
(Improve note in the middle)
```
error[E0311]: the parameter type `T` may not live long enough
--> src/main.rs:25:11
|
24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) {
| -- help: consider adding an explicit lifetime bound...: `T: 'a +`
25 | scope.spawn(move |_| {
| ^^^^^
|
note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40...
--> src/main.rs:24:40
|
24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) {
| ^^^^^
note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds
--> src/main.rs:25:11
|
25 | scope.spawn(move |_| {
| ^^^^^
```
r? ``````@estebank``````
fix the false 'defined here' messages
Closes#80853.
Take this code:
```rust
struct S;
fn repro_ref(thing: S) {
thing();
}
```
Previously, the error message would be this:
```
error[E0618]: expected function, found `S`
--> src/lib.rs:4:5
|
3 | fn repro_ref(thing: S) {
| ----- `S` defined here
4 | thing();
| ^^^^^--
| |
| call expression requires function
error: aborting due to previous error
```
This is incorrect as `S` is not defined in the function arguments, `thing` is defined there. With this change, the following is emitted:
```
error[E0618]: expected function, found `S`
--> $DIR/80853.rs:4:5
|
LL | fn repro_ref(thing: S) {
| ----- is of type `S`
LL | thing();
| ^^^^^--
| |
| call expression requires function
|
= note: local variable `S` is not a function
error: aborting due to previous error
```
As you can see, this error message points out that `thing` is of type `S` and later in a note, that `S` is not a function. This change does seem like a downside for some error messages. Take this example:
```
LL | struct Empty2;
| -------------- is of type `Empty2`
```
As you can see, the error message shows that the definition of `Empty2` is of type `Empty2`. Although this isn't wrong, it would be more helpful if it would say something like this (which was there previously):
```
LL | struct Empty2;
| -------------- `Empty2` defined here
```
If there is a better way of doing this, where the `Empty2` example would stay the same as without this change, please inform me.
**Update: This is now fixed**
CC `@camelid`
Improve suggestion for tuple struct pattern matching errors.
Closes#80174
This change allows numbers to be parsed as field names when pattern matching on structs, which allows us to provide better error messages when tuple structs are matched using a struct pattern.
r? ``@estebank``
Make "missing field" error message more natural
```rust
struct A {
x: i32,
y: i32,
z: i32,
}
fn main() {
A { };
}
```
```
error[E0063]: missing fields `x`, `y`, `z` in initializer of `A`
--> src/main.rs:8:5
|
8 | A { };
| ^ missing `x`, `y`, `z`
```
This error is now:
```
error[E0063]: missing fields `x`, `y` and `z` in initializer of `A`
--> src/main.rs:8:5
|
8 | A { };
| ^ missing `x`, `y` and `z`
```
I thought it looked nicer and more natural this way. Also, if there is >3 fields missing, there is an "and" as well ("missing \`x\`, \`y\`, \`z\` *and* 1 other field"), but for <=3 there is not. As such it improves consistency too.
As for the implementation, originally I ended up with a chunky `push_str` algorithm but then I figured I could just do the formatting manually since it's just 3 field names at maximum. It is comparatively readable.
As a sidenote, one thing I was wondering about is, isn't there more cases where you have a list of things like field names? Maybe this whole thing can at some point later be made into a more general function to be used in multiple areas.
Improve assert_eq! and assert_ne!
This PR improves `assert_eq!` and `assert_ne!` by moving the panicking code in an external function.
It does not change the fast path, but the move of the formatting in the cold path (the panic) may have a positive effect on in instruction cache use and with inlining.
Moreover, the use of trait objects instead of generic may improve compile times for `assert_eq!`-heavy code.
Godbolt link: ~~https://rust.godbolt.org/z/TYa9MT~~ \
Updated: https://rust.godbolt.org/z/bzE84x
ast: Keep expansion status for out-of-line module items
I.e. whether a module `mod foo;` is already loaded from a file or not.
This is a pre-requisite to correctly treating inner attributes on such modules (https://github.com/rust-lang/rust/issues/81661).
With this change AST structures for `mod` items diverge even more for AST structure for the crate root, which previously used `ast::Mod`.
Therefore this PR removes `ast::Mod` from `ast::Crate` in the first commit, these two things are sufficiently different from each other, at least at syntactic level.
Customization points for visiting a "`mod` item or crate root" were also removed from AST visitors (`fn visit_mod`).
`ast::Mod` itself was refactored away in the second commit in favor of `ItemKind::Mod(Unsafe, ModKind)`.
Replace if-let and while-let with `if let` and `while let`
This pull request replaces if-let and while-let with `if let` and `while let`.
closes https://github.com/rust-lang/rust/issues/82205
Crate root is sufficiently different from `mod` items, at least at syntactic level.
Also remove customization point for "`mod` item or crate root" from AST visitors.
Placeholder lifetime error cleanup
- Remove note of trait definition
- Avoid repeating the same self type
- Use original region names when possible
- Use this error kind more often
- Print closure signatures when they are suppose to implement `Fn*` traits
Works towards #57374
r? ```@nikomatsakis```
Add 'consider using' message to overflowing_literals
Fixes#79744.
Ironically, the `overflowing_literals` handler for binary or hex already
had this message! You would think it would be the other way around :)
cc ```@scottmcm```
Fixing bad suggestion for `_` in `const` type when a function #81885Closes#81885
```
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> $DIR/typeck_type_placeholder_item_help.rs:13:22
|
LL | const TEST4: fn() -> _ = 42;
| ^
| |
| not allowed in type signatures
| help: use type parameters instead: `T`
```
Do not show the suggestion `help: use type parameters instead: T` when `fn`
If we have a cause containing `ValuePairs::PolyTraitRefs` but neither
TraitRef has any escaping bound regions then we report the same error as
for `ValuePairs::TraitRefs`.
