Continuing the work started in #136466.
Every method gains a `hir_` prefix, though for the ones that already
have a `par_` or `try_par_` prefix I added the `hir_` after that.
First of all, note that `Map` has three different relevant meanings.
- The `intravisit::Map` trait.
- The `map::Map` struct.
- The `NestedFilter::Map` associated type.
The `intravisit::Map` trait is impl'd twice.
- For `!`, where the methods are all unreachable.
- For `map::Map`, which gets HIR stuff from the `TyCtxt`.
As part of getting rid of `map::Map`, this commit changes `impl
intravisit::Map for map::Map` to `impl intravisit::Map for TyCtxt`. It's
fairly straightforward except various things are renamed, because the
existing names would no longer have made sense.
- `trait intravisit::Map` becomes `trait intravisit::HirTyCtxt`, so named
because it gets some HIR stuff from a `TyCtxt`.
- `NestedFilter::Map` assoc type becomes `NestedFilter::MaybeTyCtxt`,
because it's always `!` or `TyCtxt`.
- `Visitor::nested_visit_map` becomes `Visitor::maybe_tcx`.
I deliberately made the new trait and associated type names different to
avoid the old `type Map: Map` situation, which I found confusing. We now
have `type MaybeTyCtxt: HirTyCtxt`.
The end goal is to eliminate `Map` altogether.
I added a `hir_` prefix to all of them, that seemed simplest. The
exceptions are `module_items` which became `hir_module_free_items` because
there was already a `hir_module_items`, and `items` which became
`hir_free_items` for consistency with `hir_module_free_items`.
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.
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);
| ++++++++++++++
```
Shorten error message for callable with wrong return type
```
error: expected `{closure@...}` to return `Ret`, but it returns `Other`
```
instead of
```
error: expected `{closure@...}` to be a closure that returns `Ret`, but it returns `Other`
```
Highlight clarifying information in "expected/found" error
When the expected and found types have the same textual representation, we add clarifying in parentheses. We now visually highlight it in the output.
Detect a corner case where the clarifying information would be the same for both types and skip it, as it doesn't add anything useful.
Tweak fn pointer suggestion span
Use a more targeted span when suggesting casting an `fn` item to an `fn` pointer.
```
error[E0308]: cannot coerce functions which must be inlined to function pointers
--> $DIR/cast.rs:10:33
|
LL | let _: fn(isize) -> usize = callee;
| ------------------ ^^^^^^ cannot coerce functions which must be inlined to function pointers
| |
| expected due to this
|
= note: expected fn pointer `fn(_) -> _`
found fn item `fn(_) -> _ {callee}`
= note: fn items are distinct from fn pointers
help: consider casting to a fn pointer
|
LL | let _: fn(isize) -> usize = callee as fn(isize) -> usize;
| +++++++++++++++++++++
```
```
error[E0308]: mismatched types
--> $DIR/fn-pointer-mismatch.rs:42:30
|
LL | let d: &fn(u32) -> u32 = foo;
| --------------- ^^^ expected `&fn(u32) -> u32`, found fn item
| |
| expected due to this
|
= note: expected reference `&fn(_) -> _`
found fn item `fn(_) -> _ {foo}`
help: consider using a reference
|
LL | let d: &fn(u32) -> u32 = &foo;
| +
```
Previously we'd point at the whole expression for replacement, instead of marking what was being added.
We could also modify the suggestions for `&(name as fn())`, but for that we require storing more accurate spans than we have now.
Rework "long type names" printing logic
Make it so more type-system types can be printed in a shortened version (like `Predicate`s).
Centralize printing the information about the "full type name path".
Make the "long type path" for the file where long types are written part of `Diag`, so that it becomes easier to keep track of it, and ensure it will always will be printed out last in the diagnostic by making its addition to the output implicit.
Tweak the shortening of types in "expected/found" labels.
Remove dead file `note.rs`.
When the expected and found types have the same textual representation, we add clarifying in parentheses. We now visually highlight it in the output.
Detect a corner case where the clarifying information would be the same for both types and skip it, as it doesn't add anything useful.
```
error: expected `{closure@...}` to return `Ret`, but it returns `Other`
```
instead of
```
error: expected `{closure@...}` to be a closure that returns `Ret`, but it returns `Other`
```
Use a more targeted span when suggesting casting an `fn` item to an `fn` pointer.
```
error[E0308]: cannot coerce functions which must be inlined to function pointers
--> $DIR/cast.rs:10:33
|
LL | let _: fn(isize) -> usize = callee;
| ------------------ ^^^^^^ cannot coerce functions which must be inlined to function pointers
| |
| expected due to this
|
= note: expected fn pointer `fn(_) -> _`
found fn item `fn(_) -> _ {callee}`
= note: fn items are distinct from fn pointers
help: consider casting to a fn pointer
|
LL | let _: fn(isize) -> usize = callee as fn(isize) -> usize;
| +++++++++++++++++++++
```
```
error[E0308]: mismatched types
--> $DIR/fn-pointer-mismatch.rs:42:30
|
LL | let d: &fn(u32) -> u32 = foo;
| --------------- ^^^ expected `&fn(u32) -> u32`, found fn item
| |
| expected due to this
|
= note: expected reference `&fn(_) -> _`
found fn item `fn(_) -> _ {foo}`
help: consider using a reference
|
LL | let d: &fn(u32) -> u32 = &foo;
| +
```
Previously we'd point at the whole expression for replacement, instead of marking what was being added.
We could also modify the suggestions for `&(name as fn())`, but for that we require storing more accurate spans than we have now.
Make it so more type-system types can be printed in a shortened version (like `Predicate`s).
Centralize printing the information about the "full type name path".
Make the "long type path" for the file where long types are written part of `Diag`, so that it becomes easier to keep track of it, and ensure it will always will be printed out last in the diagnostic by making its addition to the output implicit.
Tweak the shortening of types in "expected/found" labels.
Remove dead file `note.rs`.
Compiler: Finalize dyn compatibility renaming
Update the Reference link to use the new URL fragment from https://github.com/rust-lang/reference/pull/1666 (this change has finally hit stable). Fixes a FIXME.
Follow-up to #130826.
Part of #130852.
~~Blocking it on #133372.~~ (merged)
r? ghost
When encountering unexpected closure return type, point at return type/expression
```
error[E0271]: expected `{closure@fallback-closure-wrap.rs:18:40}` to be a closure that returns `()`, but it returns `!`
--> $DIR/fallback-closure-wrap.rs:19:9
|
LL | let error = Closure::wrap(Box::new(move || {
| -------
LL | panic!("Can't connect to server.");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `!`
|
= note: expected unit type `()`
found type `!`
= note: required for the cast from `Box<{closure@$DIR/fallback-closure-wrap.rs:18:40: 18:47}>` to `Box<dyn FnMut()>`
```
```
error[E0271]: expected `{closure@dont-ice-for-type-mismatch-in-closure-in-async.rs:6:10}` to be a closure that returns `bool`, but it returns `Option<()>`
--> $DIR/dont-ice-for-type-mismatch-in-closure-in-async.rs:6:16
|
LL | call(|| -> Option<()> {
| ---- ------^^^^^^^^^^
| | |
| | expected `bool`, found `Option<()>`
| required by a bound introduced by this call
|
= note: expected type `bool`
found enum `Option<()>`
note: required by a bound in `call`
--> $DIR/dont-ice-for-type-mismatch-in-closure-in-async.rs:3:25
|
LL | fn call(_: impl Fn() -> bool) {}
| ^^^^ required by this bound in `call`
```
```
error[E0271]: expected `{closure@f670.rs:28:13}` to be a closure that returns `Result<(), _>`, but it returns `!`
--> f670.rs:28:20
|
28 | let c = |e| -> ! {
| -------^
| |
| expected `Result<(), _>`, found `!`
...
32 | f().or_else(c);
| ------- required by a bound introduced by this call
-Ztrack-diagnostics: created at compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs:1433:28
|
= note: expected enum `Result<(), _>`
found type `!`
note: required by a bound in `Result::<T, E>::or_else`
--> /home/gh-estebank/rust/library/core/src/result.rs:1406:39
|
1406 | pub fn or_else<F, O: FnOnce(E) -> Result<T, F>>(self, op: O) -> Result<T, F> {
| ^^^^^^^^^^^^ required by this bound in `Result::<T, E>::or_else`
```
CC #111539.
```
error[E0271]: expected `{closure@return-type-doesnt-match-bound.rs:18:13}` to be a closure that returns `Result<(), _>`, but it returns `!`
--> tests/ui/closures/return-type-doesnt-match-bound.rs:18:20
|
18 | let c = |e| -> ! { //~ ERROR to be a closure that returns
| -------^
| |
| expected `Result<(), _>`, found `!`
...
22 | f().or_else(c);
| ------- -
| |
| required by a bound introduced by this call
|
= note: expected enum `Result<(), _>`
found type `!`
note: required by a bound in `Result::<T, E>::or_else`
--> /home/gh-estebank/rust/library/core/src/result.rs:1406:39
|
1406 | pub fn or_else<F, O: FnOnce(E) -> Result<T, F>>(self, op: O) -> Result<T, F> {
| ^^^^^^^^^^^^ required by this bound in `Result::<T, E>::or_else`
```
```
error[E0271]: expected `{closure@fallback-closure-wrap.rs:18:40}` to be a closure that returns `()`, but it returns `!`
--> $DIR/fallback-closure-wrap.rs:19:9
|
LL | let error = Closure::wrap(Box::new(move || {
| -------
LL | panic!("Can't connect to server.");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `!`
|
= note: expected unit type `()`
found type `!`
= note: required for the cast from `Box<{closure@$DIR/fallback-closure-wrap.rs:18:40: 18:47}>` to `Box<dyn FnMut()>`
```
```
error[E0271]: expected `{closure@dont-ice-for-type-mismatch-in-closure-in-async.rs:6:10}` to be a closure that returns `bool`, but it returns `Option<()>`
--> $DIR/dont-ice-for-type-mismatch-in-closure-in-async.rs:6:16
|
LL | call(|| -> Option<()> {
| ---- ------^^^^^^^^^^
| | |
| | expected `bool`, found `Option<()>`
| required by a bound introduced by this call
|
= note: expected type `bool`
found enum `Option<()>`
note: required by a bound in `call`
--> $DIR/dont-ice-for-type-mismatch-in-closure-in-async.rs:3:25
|
LL | fn call(_: impl Fn() -> bool) {}
| ^^^^ required by this bound in `call`
```
```
error[E0271]: expected `{closure@f670.rs:28:13}` to be a closure that returns `Result<(), _>`, but it returns `!`
--> f670.rs:28:20
|
28 | let c = |e| -> ! {
| -------^
| |
| expected `Result<(), _>`, found `!`
...
32 | f().or_else(c);
| ------- required by a bound introduced by this call
-Ztrack-diagnostics: created at compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs:1433:28
|
= note: expected enum `Result<(), _>`
found type `!`
note: required by a bound in `Result::<T, E>::or_else`
--> /home/gh-estebank/rust/library/core/src/result.rs:1406:39
|
1406 | pub fn or_else<F, O: FnOnce(E) -> Result<T, F>>(self, op: O) -> Result<T, F> {
| ^^^^^^^^^^^^ required by this bound in `Result::<T, E>::or_else`
```
Properly check that array length is valid type during built-in unsizing in index
This results in duplicated errors, but this class of errors is not new; in general, we aren't really equipped to detect cases where a WF error due to a field type would be shadowed by the parent struct of that field also not being WF.
This also adds a note for these types of mismatches to make it clear that this is due to an array type.
Fixes#134352
r? boxyuwu
Rename `Piece::String` to `Piece::Lit`
This renames Piece::String to Piece::Lit to avoid shadowing std::string::String and removes "pub use Piece::*;".
Use identifiers more in diagnostics code
This should make the diagnostics code slightly more correct when rendering idents in mixed crate edition situations. Kinda a no-op, but a cleanup regardless.
r? oli-obk or reassign
Use short type string in E0308 secondary span label
We were previously printing the full type on the "this expression has type" label.
```
error[E0308]: mismatched types
--> $DIR/secondary-label-with-long-type.rs:8:9
|
LL | let () = x;
| ^^ - this expression has type `((..., ..., ..., ...), ..., ..., ...)`
| |
| expected `((..., ..., ..., ...), ..., ..., ...)`, found `()`
|
= note: expected tuple `((..., ..., ..., ...), ..., ..., ...)`
found unit type `()`
= note: the full type name has been written to '$TEST_BUILD_DIR/diagnostic-width/secondary-label-with-long-type/secondary-label-with-long-type.long-type-3987761834644699448.txt'
= note: consider using `--verbose` to print the full type name to the console
```
Reported in a comment of #135919.
Forbid usage of `hir` `Infer` const/ty variants in ambiguous contexts
The feature `generic_arg_infer` allows providing `_` as an argument to const generics in order to infer them. This introduces a syntactic ambiguity as to whether generic arguments are type or const arguments. In order to get around this we introduced a fourth `GenericArg` variant, `Infer` used to represent `_` as an argument to generic parameters when we don't know if its a type or a const argument.
This made hir visitors that care about `TyKind::Infer` or `ConstArgKind::Infer` very error prone as checking for `TyKind::Infer`s in `visit_ty` would find *some* type infer arguments but not *all* of them as they would sometimes be lowered to `GenericArg::Infer` instead.
Additionally the `visit_infer` method would previously only visit `GenericArg::Infer` not *all* infers (e.g. `TyKind::Infer`), this made it very easy to override `visit_infer` and expect it to visit all infers when in reality it would only visit *some* infers.
---
This PR aims to fix those issues by making the `TyKind` and `ConstArgKind` types generic over whether the infer types/consts are represented by `Ty/ConstArgKind::Infer` or out of line (e.g. by a `GenericArg::Infer` or accessible by overiding `visit_infer`). We then make HIR Visitors convert all const args and types to the versions where infer vars are stored out of line and call `visit_infer` in cases where a `Ty`/`Const` would previously have had a `Ty/ConstArgKind::Infer` variant:
API Summary
```rust
enum AmbigArg {}
enum Ty/ConstArgKind<Unambig = ()> {
...
Infer(Unambig),
}
impl Ty/ConstArg {
fn try_as_ambig_ty/ct(self) -> Option<Ty/ConstArg<AmbigArg>>;
}
impl Ty/ConstArg<AmbigArg> {
fn as_unambig_ty/ct(self) -> Ty/ConstArg;
}
enum InferKind {
Ty(Ty),
Const(ConstArg),
Ambig(InferArg),
}
trait Visitor {
...
fn visit_ty/const_arg(&mut self, Ty/ConstArg<AmbigArg>) -> Self::Result;
fn visit_infer(&mut self, id: HirId, sp: Span, kind: InferKind) -> Self::Result;
}
// blanket impl'd, not meant to be overriden
trait VisitorExt {
fn visit_ty/const_arg_unambig(&mut self, Ty/ConstArg) -> Self::Result;
}
fn walk_unambig_ty/const_arg(&mut V, Ty/ConstArg) -> Self::Result;
fn walk_ty/const_arg(&mut V, Ty/ConstArg<AmbigArg>) -> Self::Result;
```
The end result is that `visit_infer` visits *all* infer args and is also the *only* way to visit an infer arg, `visit_ty` and `visit_const_arg` can now no longer encounter a `Ty/ConstArgKind::Infer`. Representing this in the type system means that it is now very difficult to mess things up, either accessing `TyKind::Infer` "just works" and you won't miss *some* type infers- or it doesn't work and you have to look at `visit_infer` or some `GenericArg::Infer` which forces you to think about the full complexity involved.
Unfortunately there is no lint right now about explicitly matching on uninhabited variants, I can't find the context for why this is the case 🤷♀️
I'm not convinced the framing of un/ambig ty/consts is necessarily the right one but I'm not sure what would be better. I somewhat like calling them full/partial types based on the fact that `Ty<Partial>`/`Ty<Full>` directly specifies how many of the type kinds are actually represented compared to `Ty<Ambig>` which which leaves that to the reader to figure out based on the logical consequences of it the type being in an ambiguous position.
---
tool changes have been modified in their own commits for easier reviewing by anyone getting cc'd from subtree changes. I also attempted to split out "bug fixes arising from the refactoring" into their own commit so they arent lumped in with a big general refactor commit
Fixes#112110
We were previously printing the full type on the "this expression has type" label.
```
error[E0308]: mismatched types
--> $DIR/secondary-label-with-long-type.rs:8:9
|
LL | let () = x;
| ^^ - this expression has type `((..., ..., ..., ...), ..., ..., ...)`
| |
| expected `((..., ..., ..., ...), ..., ..., ...)`, found `()`
|
= note: expected tuple `((..., ..., ..., ...), ..., ..., ...)`
found unit type `()`
= note: the full type name has been written to '$TEST_BUILD_DIR/diagnostic-width/secondary-label-with-long-type/secondary-label-with-long-type.long-type-3987761834644699448.txt'
= note: consider using `--verbose` to print the full type name to the console
```
Reported in a comment of #135919.
Add missing check for async body when suggesting await on futures.
Currently the compiler suggests adding `.await` to resolve some type conflicts without checking if the conflict happens in an async context. This can lead to the compiler suggesting `.await` in function signatures where it is invalid. Example:
```rs
trait A {
fn a() -> impl Future<Output = ()>;
}
struct B;
impl A for B {
fn a() -> impl Future<Output = impl Future<Output = ()>> {
async { async { () } }
}
}
```
```
error[E0271]: expected `impl Future<Output = impl Future<Output = ()>>` to be a future that resolves to `()`, but it resolves to `impl Future<Output = ()>`
--> bug.rs:6:15
|
6 | fn a() -> impl Future<Output = impl Future<Output = ()>> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found future
|
note: calling an async function returns a future
--> bug.rs:6:15
|
6 | fn a() -> impl Future<Output = impl Future<Output = ()>> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `A::{synthetic#0}`
--> bug.rs:2:27
|
2 | fn a() -> impl Future<Output = ()>;
| ^^^^^^^^^^^ required by this bound in `A::{synthetic#0}`
help: consider `await`ing on the `Future`
|
6 | fn a() -> impl Future<Output = impl Future<Output = ()>>.await {
| ++++++
```
The documentation of suggest_await_on_expect_found (`compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs:156`) even mentions such a check but does not actually implement it.
This PR adds that check to ensure `.await` is only suggested within async blocks.
There were 3 unit tests whose expected output needed to be changed because they had the suggestion outside of async. One of them (`tests/ui/async-await/dont-suggest-missing-await.rs`) actually tests that exact problem but expects it to be present.
Thanks to `@llenck` for initially noticing the bug and helping with fixing it
