Expect pipe symbol after closure parameter list #44332
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Does your patch fix the ICE even if there is a curly bracket mismatch: struct MyStruct;
impl MyStruct {
fn f() {|x, y} |
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It doesn't ICE. It seems that the ICE was caused by the untracked consuming of |
arielb1
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petrochenkov
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Sep 6, 2017
| @@ -4699,7 +4699,7 @@ impl<'a> Parser<'a> { | |||
| SeqSep::trailing_allowed(token::Comma), | |||
| |p| p.parse_fn_block_arg() | |||
| ); | |||
| self.bump(); | |||
| self.expect(&token::BinOp(token::Or))?; | |||
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Hmm, token::OrOr should be possible here as well in theory, e.g.
#![allow(unused)]
fn main() {
let x = |x, y| |a, b| 0; // Legal
x(1, 2)(3, 4);
}, but |x, y||a, b| 0 (without space) doesn't parse on stable/beta/nightly already.
Worth fixing as well!
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I'm trying to fix this. Should I work on this double-closure parsing bug in a new PR?
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Yes, this can be done separately to avoid blocking this PR.
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@tirr-c |
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@bors r+ |
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📌 Commit 258ec30 has been approved by |
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@bors rollup |
frewsxcv
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Sep 9, 2017
Expect pipe symbol after closure parameter list Fixes rust-lang#44021. --- Originally, the parser just called `bump` to discard following token after parsing closure parameter list, because it assumes `|` is following. However, the following code breaks the assumption: ```rust struct MyStruct; impl MyStruct { fn f() {|x, y} } ``` Here, the parameter list is `x, y` and the following token is `}`. The parser discards `}`, and then we have a curly bracket mismatch. Indeed, this code has a syntax error. On current nightly, the compiler emits an syntax error, but with incorrect message and span, followed by an ICE. ``` error: expected expression, found `}` --> 44021.rs:4:1 | 4 | } | ^ error: internal compiler error: unexpected panic ``` Even worse, on current stable(1.20.0), the compiler falls into an infinite loop. This pull request fixes this problem. Now the compiler emits correct error message and span, and does not ICE. ``` error: expected one of `:`, `@`, or `|`, found `}` --> 44021.rs:3:20 | 3 | fn foo() {|x, y} | ^ expected one of `:`, `@`, or `|` here ```
frewsxcv
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Sep 9, 2017
Expect pipe symbol after closure parameter list Fixes rust-lang#44021. --- Originally, the parser just called `bump` to discard following token after parsing closure parameter list, because it assumes `|` is following. However, the following code breaks the assumption: ```rust struct MyStruct; impl MyStruct { fn f() {|x, y} } ``` Here, the parameter list is `x, y` and the following token is `}`. The parser discards `}`, and then we have a curly bracket mismatch. Indeed, this code has a syntax error. On current nightly, the compiler emits an syntax error, but with incorrect message and span, followed by an ICE. ``` error: expected expression, found `}` --> 44021.rs:4:1 | 4 | } | ^ error: internal compiler error: unexpected panic ``` Even worse, on current stable(1.20.0), the compiler falls into an infinite loop. This pull request fixes this problem. Now the compiler emits correct error message and span, and does not ICE. ``` error: expected one of `:`, `@`, or `|`, found `}` --> 44021.rs:3:20 | 3 | fn foo() {|x, y} | ^ expected one of `:`, `@`, or `|` here ```
GuillaumeGomez
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Sep 10, 2017
Expect pipe symbol after closure parameter list Fixes rust-lang#44021. --- Originally, the parser just called `bump` to discard following token after parsing closure parameter list, because it assumes `|` is following. However, the following code breaks the assumption: ```rust struct MyStruct; impl MyStruct { fn f() {|x, y} } ``` Here, the parameter list is `x, y` and the following token is `}`. The parser discards `}`, and then we have a curly bracket mismatch. Indeed, this code has a syntax error. On current nightly, the compiler emits an syntax error, but with incorrect message and span, followed by an ICE. ``` error: expected expression, found `}` --> 44021.rs:4:1 | 4 | } | ^ error: internal compiler error: unexpected panic ``` Even worse, on current stable(1.20.0), the compiler falls into an infinite loop. This pull request fixes this problem. Now the compiler emits correct error message and span, and does not ICE. ``` error: expected one of `:`, `@`, or `|`, found `}` --> 44021.rs:3:20 | 3 | fn foo() {|x, y} | ^ expected one of `:`, `@`, or `|` here ```
bors
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bors
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Sep 14, 2017
Parse nested closure with two consecutive parameter lists properly This is a followup of #44332. --- Currently, in nightly, this does not compile: ```rust fn main() { let f = |_||x, y| x+y; println!("{}", f(())(1, 2)); // should print 3 } ``` `|_||x, y| x+y` should be parsed as `|_| (|x, y| x+y)`, but the parser didn't accept `||` between `_` and `x`. This patch fixes the problem. r? @petrochenkov
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Fixes #44021.
Originally, the parser just called
bumpto discard following token after parsing closure parameter list, because it assumes|is following. However, the following code breaks the assumption:Here, the parameter list is
x, yand the following token is}. The parser discards}, and then we have a curly bracket mismatch.Indeed, this code has a syntax error. On current nightly, the compiler emits an syntax error, but with incorrect message and span, followed by an ICE.
Even worse, on current stable(1.20.0), the compiler falls into an infinite loop.
This pull request fixes this problem. Now the compiler emits correct error message and span, and does not ICE.