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Improves parser diagnostics, fixes #93867

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This commit is contained in:
threadexception 2022-05-01 19:05:35 +02:00
parent d201c812d4
commit 21fdd549f6
22 changed files with 135 additions and 33 deletions
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20
compiler/rustc_parse/src/parser/path.rs
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@ -2,7 +2,7 @@ use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
use super::{Parser, Restrictions, TokenType};
use crate::maybe_whole;
use rustc_ast::ptr::P;
use rustc_ast::token::{self, Delimiter, Token};
use rustc_ast::token::{self, Delimiter, Token, TokenKind};
use rustc_ast::{
self as ast, AngleBracketedArg, AngleBracketedArgs, AnonConst, AssocConstraint,
AssocConstraintKind, BlockCheckMode, GenericArg, GenericArgs, Generics, ParenthesizedArgs,
@ -96,7 +96,7 @@ impl<'a> Parser<'a> {
/// ^ help: use double colon
/// ```
fn recover_colon_before_qpath_proj(&mut self) -> bool {
if self.token.kind != token::Colon
if !self.check_noexpect(&TokenKind::Colon)
|| self.look_ahead(1, |t| !t.is_ident() || t.is_reserved_ident())
{
return false;
@ -478,7 +478,7 @@ impl<'a> Parser<'a> {
while let Some(arg) = self.parse_angle_arg(ty_generics)? {
args.push(arg);
if !self.eat(&token::Comma) {
if self.token.kind == token::Semi
if self.check_noexpect(&TokenKind::Semi)
&& self.look_ahead(1, |t| t.is_ident() || t.is_lifetime())
{
// Add `>` to the list of expected tokens.
@ -517,7 +517,11 @@ impl<'a> Parser<'a> {
let arg = self.parse_generic_arg(ty_generics)?;
match arg {
Some(arg) => {
if self.check(&token::Colon) | self.check(&token::Eq) {
// we are using noexpect here because we first want to find out if either `=` or `:`
// is present and then use that info to push the other token onto the tokens list
let separated =
self.check_noexpect(&token::Colon) || self.check_noexpect(&token::Eq);
if separated && (self.check(&token::Colon) | self.check(&token::Eq)) {
let arg_span = arg.span();
let (binder, ident, gen_args) = match self.get_ident_from_generic_arg(&arg) {
Ok(ident_gen_args) => ident_gen_args,
@ -553,6 +557,14 @@ impl<'a> Parser<'a> {
AssocConstraint { id: ast::DUMMY_NODE_ID, ident, gen_args, kind, span };
Ok(Some(AngleBracketedArg::Constraint(constraint)))
} else {
// we only want to suggest `:` and `=` in contexts where the previous token
// is an ident and the current token or the next token is an ident
if self.prev_token.is_ident()
&& (self.token.is_ident() || self.look_ahead(1, |token| token.is_ident()))
{
self.check(&token::Colon);
self.check(&token::Eq);
}
Ok(Some(AngleBracketedArg::Arg(arg)))
}
}