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Detect if-else chains with a missing final else in type errors #135558

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Merged
merged 1 commit into from
Jan 17, 2025
Merged

Detect if-else chains with a missing final else in type errors #135558

merged 1 commit into from
Jan 17, 2025

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estebank
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error[E0308]: `if` and `else` have incompatible types
  --> $DIR/if-else-chain-missing-else.rs:12:12
   |
LL |        let x = if let Ok(x) = res {
   |  ______________-
LL | |          x
   | |          - expected because of this
LL | |      } else if let Err(e) = res {
   | | ____________^
LL | ||         return Err(e);
LL | ||     };
   | ||     ^
   | ||_____|
   |  |_____`if` and `else` have incompatible types
   |        expected `i32`, found `()`
   |
   = note: `if` expressions without `else` evaluate to `()`
   = note: consider adding an `else` block that evaluates to the expected type

We probably want a longer explanation and fewer spans on this case.

Partially address #133316.

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rustbot commented Jan 15, 2025

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@estebank
Detect if-else chains with a missing final else in type errors
f78a1bd 
```
error[E0308]: `if` and `else` have incompatible types
  --> $DIR/if-else-chain-missing-else.rs:12:12
   |
LL |        let x = if let Ok(x) = res {
   |  ______________-
LL | |          x
   | |          - expected because of this
LL | |      } else if let Err(e) = res {
   | | ____________^
LL | ||         return Err(e);
LL | ||     };
   | ||     ^
   | ||_____|
   |  |_____`if` and `else` have incompatible types
   |        expected `i32`, found `()`
   |
   = note: `if` expressions without `else` evaluate to `()`
   = note: consider adding an `else` block that evaluates to the expected type
```

We probably want a longer explanation and fewer spans on this case.

Partially address rust-lang#133316.
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@bors r=chenyukang

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bors commented Jan 17, 2025

📌 Commit f78a1bd has been approved by chenyukang

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 17, 2025
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Jan 17, 2025
@matthiaskrgr
Rollup merge of rust-lang#135558 - estebank:issue-133316, r=chenyukang
f477eca 
Detect if-else chains with a missing final else in type errors

```
error[E0308]: `if` and `else` have incompatible types
  --> $DIR/if-else-chain-missing-else.rs:12:12
   |
LL |        let x = if let Ok(x) = res {
   |  ______________-
LL | |          x
   | |          - expected because of this
LL | |      } else if let Err(e) = res {
   | | ____________^
LL | ||         return Err(e);
LL | ||     };
   | ||     ^
   | ||_____|
   |  |_____`if` and `else` have incompatible types
   |        expected `i32`, found `()`
   |
   = note: `if` expressions without `else` evaluate to `()`
   = note: consider adding an `else` block that evaluates to the expected type
```

We probably want a longer explanation and fewer spans on this case.

Partially address rust-lang#133316.
@matthiaskrgr matthiaskrgr mentioned this pull request Jan 17, 2025
Closed
bors added a commit to rust-lang-ci/rust that referenced this pull request Jan 17, 2025
@bors
Auto merge of rust-lang#135613 - matthiaskrgr:rollup-4m1o3zz, r=matth…
14d68e9 
…iaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#131806 (Treat other items as functions for the purpose of type-based search)
 - rust-lang#134290 (Windows x86: Change i128 to return via the vector ABI)
 - rust-lang#134980 (Location-sensitive polonius prototype: endgame)
 - rust-lang#135558 (Detect if-else chains with a missing final else in type errors)
 - rust-lang#135594 (fix error for when results in a rustdoc-js test are in the wrong order)
 - rust-lang#135601 (Fix suggestion to convert dereference of raw pointer to ref)
 - rust-lang#135604 (Expand docs for `E0207` with additional example)

r? `@ghost`
`@rustbot` modify labels: rollup
@matthiaskrgr matthiaskrgr mentioned this pull request Jan 17, 2025
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request Jan 17, 2025
@bors
Auto merge of rust-lang#135615 - matthiaskrgr:rollup-ra7vftt, r=matth…
73c0ae6 
…iaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#131806 (Treat other items as functions for the purpose of type-based search)
 - rust-lang#134980 (Location-sensitive polonius prototype: endgame)
 - rust-lang#135558 (Detect if-else chains with a missing final else in type errors)
 - rust-lang#135594 (fix error for when results in a rustdoc-js test are in the wrong order)
 - rust-lang#135601 (Fix suggestion to convert dereference of raw pointer to ref)
 - rust-lang#135604 (Expand docs for `E0207` with additional example)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit c438930 into rust-lang:master Jan 17, 2025
6 checks passed
@rustbot rustbot added this to the 1.86.0 milestone Jan 17, 2025
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Jan 17, 2025
@rust-timer
Unrolled build for rust-lang#135558
8562ed3 
Rollup merge of rust-lang#135558 - estebank:issue-133316, r=chenyukang

Detect if-else chains with a missing final else in type errors

```
error[E0308]: `if` and `else` have incompatible types
  --> $DIR/if-else-chain-missing-else.rs:12:12
   |
LL |        let x = if let Ok(x) = res {
   |  ______________-
LL | |          x
   | |          - expected because of this
LL | |      } else if let Err(e) = res {
   | | ____________^
LL | ||         return Err(e);
LL | ||     };
   | ||     ^
   | ||_____|
   |  |_____`if` and `else` have incompatible types
   |        expected `i32`, found `()`
   |
   = note: `if` expressions without `else` evaluate to `()`
   = note: consider adding an `else` block that evaluates to the expected type
```

We probably want a longer explanation and fewer spans on this case.

Partially address rust-lang#133316.
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