Incorrect bracket is pointed to for return type in closure

[varkor]

fn main() {
    let _ = || {
        if true {
            true
        } else {
            false
        } // Whoops, forgot a semicolon!
        false
    };
}

Gives the error:

error[E0308]: mismatched types
 --> src/main.rs:4:13
  |
1 | fn main() {
  |           - expected `()` because of default return type
...
4 |             true
  |             ^^^^ expected (), found bool
  |
  = note: expected type `()`
             found type `bool`

The return type of main is referenced, which is wrong — but really the problem is that there are two consecutive expressions that are not separated by a semicolon. It would be good to have an improvement in either respect, though.

[ashtneoi]

I did some poking around and it looks like it doesn't specifically involve closures. From what I saw, there are three possibly-distinct cases that trigger it, all with slightly different error messages:

1

fn main() {
    let a = { { true } true };
}

error[E0308]: mismatched types
 --> a.rs:2:17
  |
1 | fn main() {
  |           - expected `()` because of default return type
2 |     let a = { { true } true };
  |                 ^^^^ expected (), found bool
  |
  = note: expected type `()`
             found type `bool`

2

fn foo() {
    let a = { { true } true };
}

error[E0308]: mismatched types
 --> b.rs:2:17
  |
1 | fn foo() {
  |          - help: try adding a return type: `-> bool`
2 |     let a = { { true } true };
  |                 ^^^^ expected (), found bool
  |
  = note: expected type `()`
             found type `bool`

3

fn foo() -> () {
    let a = { { true } true };
}

error[E0308]: mismatched types
 --> c.rs:2:17
  |
1 | fn foo() -> () {
  |             -- expected `()` because of return type
2 |     let a = { { true } true };
  |                 ^^^^ expected (), found bool
  |
  = note: expected type `()`
             found type `bool`

---

It doesn't seem to happen with any other return type.

[estebank]

CC #46720

[estebank]

Current output:

error[E0308]: mismatched types
 --> file5.rs:4:13
  |
4 |             true
  |             ^^^^ expected (), found bool
  |
  = note: expected type `()`
             found type `bool`

error[E0308]: mismatched types
 --> file5.rs:6:13
  |
6 |             false
  |             ^^^^^ expected (), found bool
  |
  = note: expected type `()`
             found type `bool`

[varkor]

@estebank: do we have test cases for this sort of problem? It might be worth adding the test in the issue.

[estebank]

@varkor we do, can try and find them for you, but I'm 99% sure we already cover these cases.

[varkor]

I thought it was likely we did. They should be sufficient.