Fix incorrect Box::pin suggestion
The suggestion checked if `Pin<Box<T>>` could be coeerced to the expected
type, but did not check predicates created by the coercion. We now
look for predicates that definitely cannot be satisfied before giving
the suggestion.
The suggestion is still marked MaybeIncorrect because we allow predicates that
are still ambiguous and can't be proven.
Fixes#72117.
The suggestion checked if Pin<Box<T>> could be coeerced to the expected
type, but did not check predicates created by the coercion. We now
look for predicates that definitely cannot be satisfied before giving
the suggestion.
The suggestion is marked MaybeIncorrect because we allow predicates that
are still ambiguous and can't be proven.
suggestion for typoed crate or module
Previously, the compiler didn't suggest similarly named crates or modules. This pull request adds a suggestion for typoed crates or modules.
#76208
before:
```
error[E0433]: failed to resolve: use of undeclared type or module `chono`
--> src/main.rs:2:5
|
2 | use chono::prelude::*;
| ^^^^^ use of undeclared type or module `chono`
```
after:
```
error[E0433]: failed to resolve: use of undeclared type or module `chono`
--> src/main.rs:2:5
|
2 | use chono::prelude::*;
| ^^^^^
| |
| use of undeclared crate or module `chono`
| help: a similar crate or module exists: `chrono`
```
avoid suggesting the same name
sort candidates
fix a message
use `opt_def_id` instead of `def_id`
move `find_similarly_named_module_or_crate` to rustc_resolve/src/diagnostics.rs
Introduce `tcx.get_diagnostic_name`
Introduces a "reverse lookup" for diagnostic items. This is mainly intended for `@rust-lang/clippy` which often does a long series of `is_diagnostic_item` calls for the same `DefId`.
r? `@oli-obk`
Note specific regions involved in 'borrowed data escapes' error
Fixes#67007
Currently, a 'borrowed data escapes' error does not mention
the specific lifetime involved (except indirectly through a suggestion
about adding a lifetime bound). We now explain the specific lifetime
relationship that failed to hold, which improves otherwise vague
error messages.
Consider unfulfilled obligations in binop errors
When encountering a binop where the types would have been accepted, if
all the predicates had been fulfilled, include information about the
predicates and suggest appropriate `#[derive]`s if possible.
Fix#84515.
When encountering a binop where the types would have been accepted, if
all the predicates had been fulfilled, include information about the
predicates and suggest appropriate `#[derive]`s if possible.
Point at trait(s) that needs to be `impl`emented.
Fixes#67007
Currently, a 'borrowed data escapes' error does not mention
the specific lifetime involved (except indirectly through a suggestion
about adding a lifetime bound). We now explain the specific lifetime
relationship that failed to hold, which improves otherwise vague
error messages.
Fixes#73159
This is similar to #69350 - if the user didn't initially
write out a 'static lifetime, adding 'static in response to
a lifetime error is usually the wrong thing to do.
fix(lint): don't suggest refutable patterns to "fix" irrefutable bind
In function arguments and let bindings, do not suggest changing `C` to `Foo::C` unless `C` is the only variant of `Foo`, because it won't work.
The general warning is still kept, because code like this is confusing.
Fixes#88730
p.s. `src/test/ui/lint/lint-uppercase-variables.rs` already tests the one-variant case.
Suggest similarly named associated items in trait impls
Fix#85942
Previously, the compiler didn't suggest similarly named associated items unlike we do in many situations. This patch adds such diagnostics for associated functions, types, and constants.
Use larger span for adjustment THIR expressions
Currently, we use a relatively 'small' span for THIR
expressions generated by an 'adjustment' (e.g. an autoderef,
autoborrow, unsizing). As a result, if a borrow generated
by an adustment ends up causing a borrowcheck error, for example:
```rust
let mut my_var = String::new();
let my_ref = &my_var
my_var.push('a');
my_ref;
```
then the span for the mutable borrow may end up referring
to only the base expression (e.g. `my_var`), rather than
the method call which triggered the mutable borrow
(e.g. `my_var.push('a')`)
Due to a quirk of the MIR borrowck implementation,
this doesn't always get exposed in migration mode,
but it does in many cases.
This commit makes THIR building consistently use 'larger'
spans for adjustment expressions. These spans are recoded
when we first create the adjustment during typecheck. For
example, an autoref adjustment triggered by a method call
will record the span of the entire method call.
The intent of this change it make it clearer to users
when it's the specific way in which a variable is
used (for example, in a method call) that produdes
a borrowcheck error. For example, an error message
claiming that a 'mutable borrow occurs here' might
be confusing if it just points at a usage of a variable
(e.g. `my_var`), when no `&mut` is in sight. Pointing
at the entire expression should help to emphasize
that the method call itself is responsible for
the mutable borrow.
In several cases, this makes the `#![feature(nll)]` diagnostic
output match up exactly with the default (migration mode) output.
As a result, several `.nll.stderr` files end up getting removed
entirely.
In function arguments and let bindings, do not suggest changing `C` to `Foo::C`
unless `C` is the only variant of `Foo`, because it won't work.
The general warning is still kept, because code like this is confusing.
Fixes#88730
Previously, the compiler didn't suggest similarly named associated items
unlike we do in many situations. This patch adds such diagnostics for
associated functions, types and constants.
Support incremental in compiletest for non-incremental modes.
This adds first-class support for using incremental builds in non-incremental-mode tests. These tests previously manually passed `-C incremental=tmp/foo` which resulted in reusing the same tmp folder between runs. This means that these tests could fail whenever the on-disk incremental format changed (such as when updating one's local source tree). This changes it so that these tests can pass a `// incremental-build` header which instructs compiletest to create a set aside a dedicated incremental directory which will be cleared before the test starts to ensure it has a clean slate.
Currently, we use a relatively 'small' span for THIR
expressions generated by an 'adjustment' (e.g. an autoderef,
autoborrow, unsizing). As a result, if a borrow generated
by an adustment ends up causing a borrowcheck error, for example:
```rust
let mut my_var = String::new();
let my_ref = &my_var
my_var.push('a');
my_ref;
```
then the span for the mutable borrow may end up referring
to only the base expression (e.g. `my_var`), rather than
the method call which triggered the mutable borrow
(e.g. `my_var.push('a')`)
Due to a quirk of the MIR borrowck implementation,
this doesn't always get exposed in migration mode,
but it does in many cases.
This commit makes THIR building consistently use 'larger'
spans for adjustment expressions
The intent of this change it make it clearer to users
when it's the specific way in which a variable is
used (for example, in a method call) that produdes
a borrowcheck error. For example, an error message
claiming that a 'mutable borrow occurs here' might
be confusing if it just points at a usage of a variable
(e.g. `my_var`), when no `&mut` is in sight. Pointing
at the entire expression should help to emphasize
that the method call itself is responsible for
the mutable borrow.
In several cases, this makes the `#![feature(nll)]` diagnostic
output match up exactly with the default (migration mode) output.
As a result, several `.nll.stderr` files end up getting removed
entirely.
Point to closure when emitting 'cannot move out' for captured variable
Attempts to fix#87456. The error message now points to the capturing closure, but I was not able to explain _why_ the closure implements `Fn` or `FnMut` (`TypeckResults::closure_kind_origins` did not contain anything for the closure in question).
cc `@Aaron1011`
Point at argument instead of call for their obligations
When an obligation is introduced by a specific `fn` argument, point at
the argument instead of the `fn` call if the obligation fails to be
fulfilled.
Move the information about pointing at the call argument expression in
an unmet obligation span from the `FulfillmentError` to a new
`ObligationCauseCode`.
When giving an error about an obligation introduced by a function call
that an argument doesn't fulfill, and that argument is a block, add a
span_label pointing at the innermost tail expression.
Current output:
```
error[E0425]: cannot find value `x` in this scope
--> f10.rs:4:14
|
4 | Some(x * 2)
| ^ not found in this scope
error[E0277]: expected a `FnOnce<({integer},)>` closure, found `Option<_>`
--> f10.rs:2:31
|
2 | let p = Some(45).and_then({
| ______________________--------_^
| | |
| | required by a bound introduced by this call
3 | | |x| println!("doubling {}", x);
4 | | Some(x * 2)
| | -----------
5 | | });
| |_____^ expected an `FnOnce<({integer},)>` closure, found `Option<_>`
|
= help: the trait `FnOnce<({integer},)>` is not implemented for `Option<_>`
```
Previous output:
```
error[E0425]: cannot find value `x` in this scope
--> f10.rs:4:14
|
4 | Some(x * 2)
| ^ not found in this scope
error[E0277]: expected a `FnOnce<({integer},)>` closure, found `Option<_>`
--> f10.rs:2:22
|
2 | let p = Some(45).and_then({
| ^^^^^^^^ expected an `FnOnce<({integer},)>` closure, found `Option<_>`
|
= help: the trait `FnOnce<({integer},)>` is not implemented for `Option<_>`
```
Partially address #27300. Will require rebasing on top of #88546.
When evaluating an `ExprKind::Call`, we first have to `check_expr` on it's
callee. When this one is a `ExprKind::Path`, we had to evaluate the bounds
introduced for its arguments, but by the time we evaluated them we no
longer had access to the argument spans. Now we special case this so
that we can point at the right place on unsatisfied bounds. This also
allows the E0277 deduplication to kick in correctly, so we now emit
fewer errors.
Use smaller spans for some structured suggestions
Use more accurate suggestion spans for
* argument parse error
* fully qualified path
* missing code block type
* numeric casts
Improve structured tuple struct suggestion
Previously, the span was just for the constructor name, which meant it
would result in syntactically-invalid code when applied. Now, the span
is for the entire expression.
I also changed it to use `span_suggestion_verbose`, for two reasons:
1. Now that the suggestion span has been corrected, the output is a bit
cluttered and hard to read. Putting the suggestion its own window
creates more space.
2. It's easier to see what's being suggested, since now the version
after the suggestion is applied is shown.
r? `@davidtwco`
For two reasons:
1. Now that the suggestion span has been corrected, the output is a bit
cluttered and hard to read. Putting the suggestion its own window
creates more space.
2. It's easier to see what's being suggested, since now the version
after the suggestion is applied is shown.
