add suggestion for inverted function parameters

Fixes #54065.
This commit is contained in:
Andy Russell 2018-10-03 22:21:05 -04:00
parent 6ddab3e078
commit f5db411410
No known key found for this signature in database
GPG Key ID: BE2221033EDBC374
3 changed files with 106 additions and 1 deletions

View File

@ -1777,7 +1777,26 @@ impl<'a> Parser<'a> {
require_name);
let pat = self.parse_pat()?;
self.expect(&token::Colon)?;
if let Err(mut err) = self.expect(&token::Colon) {
// If we find a pattern followed by an identifier, it could be an (incorrect)
// C-style parameter declaration.
if self.check_ident() && self.look_ahead(1, |t| {
*t == token::Comma || *t == token::CloseDelim(token::Paren)
}) {
let ident = self.parse_ident().unwrap();
let span = pat.span.with_hi(ident.span.hi());
err.span_suggestion_with_applicability(
span,
"declare the type after the parameter binding",
String::from("<identifier>: <type>"),
Applicability::HasPlaceholders,
);
}
return Err(err);
}
(pat, self.parse_ty()?)
} else {
debug!("parse_arg_general ident_to_pat");

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@ -0,0 +1,39 @@
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
struct S;
impl S {
fn foo(&self, &str bar) {}
//~^ ERROR expected one of `:` or `@`
//~| HELP declare the type after the parameter binding
//~| SUGGESTION <identifier>: <type>
}
fn baz(S quux, xyzzy: i32) {}
//~^ ERROR expected one of `:` or `@`
//~| HELP declare the type after the parameter binding
//~| SUGGESTION <identifier>: <type>
fn one(i32 a b) {}
//~^ ERROR expected one of `:` or `@`
fn pattern((i32, i32) (a, b)) {}
//~^ ERROR expected `:`
fn fizz(i32) {}
//~^ ERROR expected one of `:` or `@`
fn missing_colon(quux S) {}
//~^ ERROR expected one of `:` or `@`
//~| HELP declare the type after the parameter binding
//~| SUGGESTION <identifier>: <type>
fn main() {}

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@ -0,0 +1,47 @@
error: expected one of `:` or `@`, found `bar`
--> $DIR/inverted-parameters.rs:14:24
|
LL | fn foo(&self, &str bar) {}
| -----^^^
| | |
| | expected one of `:` or `@` here
| help: declare the type after the parameter binding: `<identifier>: <type>`
error: expected one of `:` or `@`, found `quux`
--> $DIR/inverted-parameters.rs:20:10
|
LL | fn baz(S quux, xyzzy: i32) {}
| --^^^^
| | |
| | expected one of `:` or `@` here
| help: declare the type after the parameter binding: `<identifier>: <type>`
error: expected one of `:` or `@`, found `a`
--> $DIR/inverted-parameters.rs:25:12
|
LL | fn one(i32 a b) {}
| ^ expected one of `:` or `@` here
error: expected `:`, found `(`
--> $DIR/inverted-parameters.rs:28:23
|
LL | fn pattern((i32, i32) (a, b)) {}
| ^ expected `:`
error: expected one of `:` or `@`, found `)`
--> $DIR/inverted-parameters.rs:31:12
|
LL | fn fizz(i32) {}
| ^ expected one of `:` or `@` here
error: expected one of `:` or `@`, found `S`
--> $DIR/inverted-parameters.rs:34:23
|
LL | fn missing_colon(quux S) {}
| -----^
| | |
| | expected one of `:` or `@` here
| help: declare the type after the parameter binding: `<identifier>: <type>`
error: aborting due to 6 previous errors