Rollup merge of #111181 - bvanjoi:fix-issue-111148, r=davidtwco

fix(parse): return unpected when current token is EOF

close https://github.com/rust-lang/rust/issues/111148

#111148 panic occurred because [FatalError.raise()](https://github.com/bvanjoi/rust/blob/master/compiler/rustc_parse/src/parser/mod.rs#LL540C3-L540C3) was encountered which caused by `Eof` and `Pound`(the last token) had same span, when parsing `#` in `fn a<<i<Y<w<>#`.

<img width="825" alt="image" src="https://user-images.githubusercontent.com/30187863/236612589-9e2c6a0b-18cd-408c-b636-c12a51cbcf1c.png">

There are a few ways to solve this problem:

- Change the action assign for [self.last_unexpected_token_span](https://github.com/rust-lang/rust/blob/master/compiler/rustc_parse/src/parser/diagnostics.rs#L592), for example, if current token is `Eof`, then return Error directly.
- Avoid triggering the `FatalError` when the current token is `Eof`.

I have chosen the second option because executing `expected_one_of_not_found` when the token is `Eof` but not in `ediable` seems reasonable.
This commit is contained in:
Matthias Krüger 2023-05-27 20:40:28 +02:00 committed by GitHub
commit 97fae38bf9
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3 changed files with 13 additions and 1 deletions

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@ -536,7 +536,9 @@ pub fn expect_one_of(
} else if inedible.contains(&self.token.kind) {
// leave it in the input
Ok(false)
} else if self.last_unexpected_token_span == Some(self.token.span) {
} else if self.token.kind != token::Eof
&& self.last_unexpected_token_span == Some(self.token.span)
{
FatalError.raise();
} else {
self.expected_one_of_not_found(edible, inedible)

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@ -0,0 +1,2 @@
fn a<<i<Y<w<>#
//~^ ERROR expected one of `#`, `>`, `const`, identifier, or lifetime, found `<`

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@ -0,0 +1,8 @@
error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `<`
--> $DIR/issue-111148.rs:1:6
|
LL | fn a<<i<Y<w<>#
| ^ expected one of `#`, `>`, `const`, identifier, or lifetime
error: aborting due to previous error