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add hint for =< as <=#111230

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zacklukem:eq-less-to-less-eq
May 6, 2023
Merged

add hint for =< as <=#111230
bors merged 1 commit intorust-lang:masterfrom
zacklukem:eq-less-to-less-eq

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@zacklukem zacklukem commented May 5, 2023

Adds a compiler hint for when =< is typed instead of <=

Example hint:

fn foo() {
    if 1 =< 3 {
        println!("Hello, World!");
    }
}
error: expected type, found `3`
 --> main.rs:2:13
  |
2 |     if 1 =< 3 {
  |          -- ^ expected type
  |          |
  |          help: did you mean: `<=`

This PR only emits the suggestion if there is no space between the = and <. This hopefully narrows the scope of when this error is emitted, however this still allows this error to be emitted in cases such as this:

error: expected expression, found `;`
 --> main.rs:2:18
  |
2 |     if 1 =< [i32;; 3]>::hello() {
  |          --      ^ expected expression
  |          |
  |          help: did you mean: `<=`

Which could be a good reason not to merge since I haven't been able to think of any other ways of narrowing the scope of this diagnostic.

closes #111128

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rustbot commented May 5, 2023

r? @oli-obk

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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 5, 2023
compiler-errors
compiler-errors reviewed May 5, 2023
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Comment thread compiler/rustc_parse/src/parser/expr.rs Outdated
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oli-obk commented May 5, 2023

I am wondering if the current logic could end up with weird spans in case of x =thing!() where thing!() expands to something starting with <. I can't come up with anything as a test, but maybe we should still guard against it by requiring that the spans' expansion info is the same?

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compiler-errors commented May 5, 2023

This happens before macro expansion though. I don't think we need that extra commit on top.

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oli-obk commented May 5, 2023

😆 too many reviewers. Seems fine to me to leave out the last commit since this can't happen. We don't re-parse the macro expansion in its context, but instead parse it as an expression.

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compiler-errors commented May 5, 2023

Drop that commit, squash the rest of the commits into one then r=me

@zacklukem zacklukem force-pushed the eq-less-to-less-eq branch from c59e887 to a183ac6 Compare May 5, 2023 15:17
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oli-obk commented May 5, 2023

@bors r=compiler-errors

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bors commented May 5, 2023

📌 Commit a183ac6 has been approved by compiler-errors

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 May 5, 2023
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request May 5, 2023
@matthiaskrgr
Rollup merge of rust-lang#111230 - zacklukem:eq-less-to-less-eq, r=co…
dedc891 
…mpiler-errors

add hint for =< as <=

Adds a compiler hint for when `=<` is typed instead of `<=`

Example hint:
```rust
fn foo() {
    if 1 =< 3 {
        println!("Hello, World!");
    }
}
```
```
error: expected type, found `3`
 --> main.rs:2:13
  |
2 |     if 1 =< 3 {
  |          -- ^ expected type
  |          |
  |          help: did you mean: `<=`
```

This PR only emits the suggestion if there is no space between the `=` and `<`.  This hopefully narrows the scope of when this error is emitted, however this still allows this error to be emitted in cases such as this:
```
error: expected expression, found `;`
 --> main.rs:2:18
  |
2 |     if 1 =< [i32;; 3]>::hello() {
  |          --      ^ expected expression
  |          |
  |          help: did you mean: `<=`
```

Which could be a good reason not to merge since I haven't been able to think of any other ways of narrowing the scope of this diagnostic.

closes rust-lang#111128
This was referenced May 5, 2023
Closed
Closed
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request May 6, 2023
@matthiaskrgr
Rollup merge of rust-lang#111230 - zacklukem:eq-less-to-less-eq, r=co…
a08e689 
…mpiler-errors

add hint for =< as <=

Adds a compiler hint for when `=<` is typed instead of `<=`

Example hint:
```rust
fn foo() {
    if 1 =< 3 {
        println!("Hello, World!");
    }
}
```
```
error: expected type, found `3`
 --> main.rs:2:13
  |
2 |     if 1 =< 3 {
  |          -- ^ expected type
  |          |
  |          help: did you mean: `<=`
```

This PR only emits the suggestion if there is no space between the `=` and `<`.  This hopefully narrows the scope of when this error is emitted, however this still allows this error to be emitted in cases such as this:
```
error: expected expression, found `;`
 --> main.rs:2:18
  |
2 |     if 1 =< [i32;; 3]>::hello() {
  |          --      ^ expected expression
  |          |
  |          help: did you mean: `<=`
```

Which could be a good reason not to merge since I haven't been able to think of any other ways of narrowing the scope of this diagnostic.

closes rust-lang#111128
@matthiaskrgr matthiaskrgr mentioned this pull request May 6, 2023
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request May 6, 2023
@bors
Auto merge of rust-lang#111287 - matthiaskrgr:rollup-9lzax2c, r=matth…
905d5a3 
…iaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#110577 (Use fulfillment to check `Drop` impl compatibility)
 - rust-lang#110610 (Add Terminator conversion from MIR to SMIR, part #1)
 - rust-lang#110985 (Fix spans in LLVM-generated inline asm errors)
 - rust-lang#110989 (Make the BUG_REPORT_URL configurable by tools )
 - rust-lang#111167 (debuginfo: split method declaration and definition)
 - rust-lang#111230 (add hint for =< as <=)
 - rust-lang#111279 (More robust debug assertions for `Instance::resolve` on built-in traits with non-standard trait items)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 83b29ec into rust-lang:master May 6, 2023
@rustbot rustbot added this to the 1.71.0 milestone May 6, 2023
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Successfully merging this pull request may close these issues.

Writing =< instead of <= gives an error about types

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@zacklukem @rustbot @oli-obk @compiler-errors @bors