This converts all of borrowck's `mut` suggestions to a new
`mc::ImmutabilityBlame` API instead of the current mix of various hacks.
Fixes#35937.
Fixes#40823.
Fix suggestion span error with a line containing multibyte characters
This PR fixes broken suggestions caused by multibyte characters.
e.g. for this code, rustc provides a broken suggestion ([playground](https://is.gd/DWGLu7)):
```rust
fn main() {
let tup = (1,);
println!("☃{}", tup[0]);
}
```
```
error: cannot index a value of type `({integer},)`
--> <anon>:3:21
|
3 | println!("☃{}", tup[0]);
| ^^^^^^
|
help: to access tuple elements, use tuple indexing syntax as shown
| println!("☃{}"tup.00]);
error: aborting due to previous error
```
`CodeSuggestion::splice_lines` is misusing `Loc.col` (`CharPos`) as a byte offset when slicing source.
When declaring nested unsafe blocks (`unsafe {unsafe {}}`) that trigger
the "unnecessary `unsafe` block" error, point out the enclosing `unsafe
block` or `unsafe fn` that makes it unnecessary.
Group "missing variable bind" spans in `or` matches and clarify wording
for the two possible cases: when a variable from the first pattern is
not in any of the subsequent patterns, and when a variable in any of the
other patterns is not in the first one.
Before:
```
error[E0408]: variable `a` from pattern #1 is not bound in pattern #2
--> file.rs:10:23
|
10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); }
| ^^^^^^^^^^^ pattern doesn't bind `a`
error[E0408]: variable `b` from pattern #2 is not bound in pattern #1
--> file.rs:10:32
|
10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); }
| ^ pattern doesn't bind `b`
error[E0408]: variable `a` from pattern #1 is not bound in pattern #3
--> file.rs:10:37
|
10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); }
| ^^^^^^^^ pattern doesn't bind `a`
error[E0408]: variable `d` from pattern #1 is not bound in pattern #3
--> file.rs:10:37
|
10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); }
| ^^^^^^^^ pattern doesn't bind `d`
error[E0408]: variable `c` from pattern #3 is not bound in pattern #1
--> file.rs:10:43
|
10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); }
| ^ pattern doesn't bind `c`
error[E0408]: variable `d` from pattern #1 is not bound in pattern #4
--> file.rs:10:48
|
10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); }
| ^^^^^^^^ pattern doesn't bind `d`
error: aborting due to 6 previous errors
```
After:
```
error[E0408]: variable `a` is not bound in all patterns
--> file.rs:20:37
|
20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => {
intln!("{:?}", a); }
| - ^^^^^^^^^^^ ^^^^^^^^ - variable
t in all patterns
| | | |
| | | pattern doesn't bind `a`
| | pattern doesn't bind `a`
| variable not in all patterns
error[E0408]: variable `d` is not bound in all patterns
--> file.rs:20:37
|
20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => {
intln!("{:?}", a); }
| - - ^^^^^^^^ ^^^^^^^^ pattern
esn't bind `d`
| | | |
| | | pattern doesn't bind `d`
| | variable not in all patterns
| variable not in all patterns
error[E0408]: variable `b` is not bound in all patterns
--> file.rs:20:37
|
20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => {
intln!("{:?}", a); }
| ^^^^^^^^^^^ - ^^^^^^^^ ^^^^^^^^ pattern
esn't bind `b`
| | | |
| | | pattern doesn't bind `b`
| | variable not in all patterns
| pattern doesn't bind `b`
error[E0408]: variable `c` is not bound in all patterns
--> file.rs:20:48
|
20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => {
intln!("{:?}", a); }
| ^^^^^^^^^^^ ^^^^^^^^^^^ - ^^^^^^^^ pattern
esn't bind `c`
| | | |
| | | variable not in all
tterns
| | pattern doesn't bind `c`
| pattern doesn't bind `c`
error: aborting due to 4 previous errors
```
* Have only one presentation for binding consistency errors
* Point to same binding in multiple patterns when possible
* Check inconsistent bindings in all arms
* Simplify wording of diagnostic message
* Sort emition and spans of binding errors for deterministic output
Warning or error messages set via a lint group attribute
(e.g. `#[deny(warnings)]`) should still make it clear which individual
lint (by name) was triggered, similarly to how we include "on by
default" language for default lints. This—and, while we're here, the
existing "on by default" language—can be tucked into a note rather than
cluttering the main error message. This occasions the slightest of
refactorings (we now have to get the diagnostic-builder with the main
message first, before matching on the lint source).
This is in the matter of #36846.
Add clearer error message using `&str + &str`
This is the first part of #39018. One of the common things for new users
coming from more dynamic languages like JavaScript, Python or Ruby is to
use `+` to concatenate strings. However, this doesn't work that way in
Rust unless the first type is a `String`. This commit adds a check for
this use case and outputs a new error as well as a suggestion to guide
the user towards the desired behavior. It also adds a new test case to
test the output of the error.
This is the first part of #39018. One of the common things for new users
coming from more dynamic languages like JavaScript, Python or Ruby is to
use `+` to concatenate strings. However, this doesn't work that way in
Rust unless the first type is a `String`. This commit adds a check for
this use case and outputs a new error as well as a suggestion to guide
the user towards the desired behavior. It also adds a new test case to
test the output of the error.
Point to immutable borrow arguments and fields when trying to use them as
mutable borrows. Add label to primary span on "cannot borrow as mutable"
errors.
Present the following output when trying to access an immutable borrow's
field as mutable:
```
error[E0389]: cannot borrow data mutably in a `&` reference
--> $DIR/issue-38147-1.rs:27:9
|
26 | fn f(&self) {
| ----- use `&mut self` here to make mutable
27 | f.s.push('x');
| ^^^ assignment into an immutable reference
```
And the following when trying to access an immutable struct field as mutable:
```
error: cannot borrow immutable borrowed content `*self.s` as mutable
--> $DIR/issue-38147-3.rs:17:9
|
12 | s: &'a String
| ------------- use `&'a mut String` here to make mutable
...|
16 | fn f(&self) {
| ----- use `&mut self` here to make mutable
17 | self.s.push('x');
| ^^^^^^ cannot borrow as mutable
```
Use multiline Diagnostic for candidate in other module
```
error[E0574]: expected struct, variant or union type, found enum `Result`
--> $DIR/issue-16058.rs:19:9
|
19 | Result {
| ^^^^^^ not a struct, variant or union type
|
= help: possible better candidates are found in other modules, you can import them into scope:
`use std::fmt::Result;`
`use std::io::Result;`
`use std:🧵:Result;`
error: aborting due to previous error
```
E0034: provide disambiguated syntax for candidates
For a given file
```rust
trait A { fn foo(&self) {} }
trait B : A { fn foo(&self) {} }
fn bar<T: B>(a: &T) {
a.foo()
}
```
provide the following output
```
error[E0034]: multiple applicable items in scope
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^ multiple `foo` found
|
note: candidate #1 is defined in the trait `A`
--> file.rs:2:11
|
2 | trait A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `A::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
note: candidate #2 is defined in the trait `B`
--> file.rs:3:15
|
3 | trait B : A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `B::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
```
Fix#37767.
Fix lint attributes on non-item nodes.
Currently, late lint checking uses two HIR visitors: LateContext and
IdVisitor. IdVisitor only overrides visit_id, and for each node searches
for builtin lints previously added to the session; LateContext overrides
a number of methods, and runs late lints. When LateContext encounters an
item, it first has IdVisitor walk everything in it except nested items
(OnlyBodies), then recurses into it itself - i.e. there are two separate
walks.
Aside from apparently being unnecessary, this separation prevents lint
attributes (allow/deny/warn) on non-item HIR nodes from working
properly. Test case:
```rust
// generates warning without this change
fn main() { #[allow(unreachable_code)] loop { break; break; } }
```
LateContext contains logic to merge attributes seen into the current lint
settings while walking (with_lint_attrs), but IdVisitor does not. So
such attributes will affect late lints (because they are called from
LateContext), and if the node contains any items within it, they will
affect builtin lints within those items (because that IdVisitor is run
while LateContext is within the attributed node), but otherwise the
attributes will be ignored for builtin lints.
This change simply removes IdVisitor and moves its visit_id into
LateContext itself. Hopefully this doesn't break anything...
Also added walk calls to visit_lifetime and visit_lifetime_def
respectively, so visit_lifetime_def will recurse into the lifetime and
visit_lifetime will recurse into the name. In principle this could
confuse lint plugins. This is "necessary" because walk_lifetime calls
visit_id on the lifetime; of course, an alternative would be directly
calling visit_id (which would require manually iterating over the
lifetimes in visit_lifetime_def), but that seems less clean.
Use multiline Diagnostic for "relevant impl" list
Provide the following output:
```
error[E0277]: the trait bound `Bar: Foo<usize>` is not satisfied
--> $DIR/issue-21659-show-relevant-trait-impls-2.rs:38:8
|
38 | f1.foo(1usize);
| ^^^ the trait `Foo<usize>` is not implemented for `Bar`
|
= help: the following implementations were found:
<Bar as Foo<i8>>
<Bar as Foo<i16>>
<Bar as Foo<i32>>
<Bar as Foo<u8>>
and 2 others
error: aborting due to previous error
```
instead of
```
error[E0277]: the trait bound `Bar: Foo<usize>` is not satisfied
--> $DIR/issue-21659-show-relevant-trait-impls-2.rs:38:8
|
38 | f1.foo(1usize);
| ^^^ the trait `Foo<usize>` is not implemented for `Bar`
|
= help: the following implementations were found:
= help: <Bar as Foo<i8>>
= help: <Bar as Foo<i16>>
= help: <Bar as Foo<i32>>
= help: <Bar as Foo<u8>>
= help: and 2 others
error: aborting due to previous error
```
Provide the following output:
```
error[E0277]: the trait bound `Bar: Foo<usize>` is not satisfied
--> $DIR/issue-21659-show-relevant-trait-impls-2.rs:38:8
|
38 | f1.foo(1usize);
| ^^^ the trait `Foo<usize>` is not implemented for `Bar`
|
= help: the following implementations were found:
<Bar as Foo<i8>>
<Bar as Foo<i16>>
<Bar as Foo<i32>>
<Bar as Foo<u8>>
and 2 others
error: aborting due to previous error
```
instead of
```
error[E0277]: the trait bound `Bar: Foo<usize>` is not satisfied
--> $DIR/issue-21659-show-relevant-trait-impls-2.rs:38:8
|
38 | f1.foo(1usize);
| ^^^ the trait `Foo<usize>` is not implemented for `Bar`
|
= help: the following implementations were found:
= help: <Bar as Foo<i8>>
= help: <Bar as Foo<i16>>
= help: <Bar as Foo<i32>>
= help: <Bar as Foo<u8>>
= help: and 2 others
error: aborting due to previous error
```
For a given file
```rust
trait A { fn foo(&self) {} }
trait B : A { fn foo(&self) {} }
fn bar<T: B>(a: &T) {
a.foo()
}
```
provide the following output
```
error[E0034]: multiple applicable items in scope
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^ multiple `foo` found
|
note: candidate #1 is defined in the trait `A`
--> file.rs:2:11
|
2 | trait A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `A::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
note: candidate #2 is defined in the trait `B`
--> file.rs:3:15
|
3 | trait B : A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `B::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
```
Teach diagnostics to correct margin of multiline messages
Make the suggestion list have a correct padding:
```
error[E0308]: mismatched types
--> file.rs:3:20
|
3 | let x: usize = "";
| ^^ expected usize, found reference
|
= note: expected type `usize`
= note: found type `&'static str`
= help: here are some functions which might fulfill your needs:
- .len()
- .foo()
- .bar()
```
Make the suggestion list have a correct padding:
```
error[E0308]: mismatched types
--> file.rs:3:20
|
3 | let x: usize = "";
| ^^ expected usize, found reference
|
= note: expected type `usize`
= note: found type `&'static str`
= help: here are some functions which might fulfill your needs:
- .len()
- .foo()
- .bar()
```
Point arg num mismatch errors back to their definition
This PR updates the arg num errors (like E0061) to point back at the function definition where they were defined.
Before:
```
error[E0061]: this function takes 2 parameters but 1 parameter was supplied
--> E0061.rs:18:7
|
18 | f(0);
| ^
|
= note: the following parameter types were expected:
= note: u16, &str
```
Now:
```
error[E0061]: this function takes 2 parameters but 1 parameter was supplied
--> E0061.rs:18:7
|
11 | fn f(a: u16, b: &str) {}
| ------------------------ defined here
...
18 | f(0);
| ^ expected 2 parameters
```
This is an incremental improvement. We probably want to underline only the function name and also have support for functions defined in crates outside of the current crate.
r? @nikomatsakis
Show `Trait` instead of `<Struct as Trait>` in E0323
For a given file
```
trait Foo {
fn bar(&self);
}
pub struct FooConstForMethod;
impl Foo for FooConstForMethod {
const bar: u64 = 1;
}
```
show
```
error[E0323]: item `bar` is an associated const, which doesn't match its trait `Foo`
```
instead of
```
error[E0323]: item `bar` is an associated const, which doesn't match its trait `<FooConstForMethod as Foo>`
```
Fix#37618
