bjoernager/rust
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Prepare for invisible delimiters.

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Current places where `Interpolated` is used are going to change to
instead use invisible delimiters. This prepares for that.
- It adds invisible delimiter cases to the `can_begin_*`/`may_be_*`
  methods and the `failed_to_match_macro` that are equivalent to the
  existing `Interpolated` cases.
- It adds panics/asserts in some places where invisible delimiters
  should never occur.
- In `Parser::parse_struct_fields` it excludes an ident + invisible
  delimiter from special consideration in an error message, because
  that's quite different to an ident + paren/brace/bracket.
This commit is contained in:
Nicholas Nethercote 2024-04-17 09:37:00 +10:00
parent cfafa9380b
commit cee88f7a3f
5 changed files with 108 additions and 14 deletions
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16
compiler/rustc_parse/src/lexer/tokentrees.rs
View file

@ -43,11 +43,19 @@ impl<'psess, 'src> TokenTreesReader<'psess, 'src> {
let mut buf = Vec::new();
loop {
match self.token.kind {
token::OpenDelim(delim) => buf.push(match self.lex_token_tree_open_delim(delim) {
Ok(val) => val,
Err(errs) => return (open_spacing, TokenStream::new(buf), Err(errs)),
}),
token::OpenDelim(delim) => {
// Invisible delimiters cannot occur here because `TokenTreesReader` parses
// code directly from strings, with no macro expansion involved.
debug_assert!(!matches!(delim, Delimiter::Invisible(_)));
buf.push(match self.lex_token_tree_open_delim(delim) {
Ok(val) => val,
Err(errs) => return (open_spacing, TokenStream::new(buf), Err(errs)),
})
}
token::CloseDelim(delim) => {
// Invisible delimiters cannot occur here because `TokenTreesReader` parses
// code directly from strings, with no macro expansion involved.
debug_assert!(!matches!(delim, Delimiter::Invisible(_)));
return (
open_spacing,
TokenStream::new(buf),

12
compiler/rustc_parse/src/parser/expr.rs
View file

@ -3591,11 +3591,19 @@ impl<'a> Parser<'a> {
&& !self.token.is_reserved_ident()
&& self.look_ahead(1, |t| {
AssocOp::from_token(t).is_some()
|| matches!(t.kind, token::OpenDelim(_))
|| matches!(
t.kind,
token::OpenDelim(
Delimiter::Parenthesis
| Delimiter::Bracket
| Delimiter::Brace
)
)
|| *t == token::Dot
})
{
// Looks like they tried to write a shorthand, complex expression.
// Looks like they tried to write a shorthand, complex expression,
// E.g.: `n + m`, `f(a)`, `a[i]`, `S { x: 3 }`, or `x.y`.
e.span_suggestion_verbose(
self.token.span.shrink_to_lo(),
"try naming a field",

50
compiler/rustc_parse/src/parser/nonterminal.rs
View file

@ -3,7 +3,9 @@ use rustc_ast::ptr::P;
use rustc_ast::token::Nonterminal::*;
use rustc_ast::token::NtExprKind::*;
use rustc_ast::token::NtPatKind::*;
use rustc_ast::token::{self, Delimiter, NonterminalKind, Token};
use rustc_ast::token::{
self, Delimiter, InvisibleOrigin, MetaVarKind, Nonterminal, NonterminalKind, Token,
};
use rustc_ast_pretty::pprust;
use rustc_data_structures::sync::Lrc;
use rustc_errors::PResult;
@ -22,7 +24,28 @@ impl<'a> Parser<'a> {
#[inline]
pub fn nonterminal_may_begin_with(kind: NonterminalKind, token: &Token) -> bool {
/// Checks whether the non-terminal may contain a single (non-keyword) identifier.
fn may_be_ident(nt: &token::Nonterminal) -> bool {
fn may_be_ident(kind: MetaVarKind) -> bool {
match kind {
MetaVarKind::Stmt
| MetaVarKind::Pat(_)
| MetaVarKind::Expr { .. }
| MetaVarKind::Ty
| MetaVarKind::Literal // `true`, `false`
| MetaVarKind::Meta
| MetaVarKind::Path => true,
MetaVarKind::Item
| MetaVarKind::Block
| MetaVarKind::Vis => false,
MetaVarKind::Ident
| MetaVarKind::Lifetime
| MetaVarKind::TT => unreachable!(),
}
}
/// Old variant of `may_be_ident`. Being phased out.
fn nt_may_be_ident(nt: &Nonterminal) -> bool {
match nt {
NtStmt(_)
| NtPat(_)
@ -69,7 +92,8 @@ impl<'a> Parser<'a> {
| token::Ident(..)
| token::NtIdent(..)
| token::NtLifetime(..)
| token::Interpolated(_) => true,
| token::Interpolated(_)
| token::OpenDelim(Delimiter::Invisible(InvisibleOrigin::MetaVar(_))) => true,
_ => token.can_begin_type(),
},
NonterminalKind::Block => match &token.kind {
@ -79,11 +103,29 @@ impl<'a> Parser<'a> {
NtBlock(_) | NtStmt(_) | NtExpr(_) | NtLiteral(_) => true,
NtItem(_) | NtPat(_) | NtTy(_) | NtMeta(_) | NtPath(_) | NtVis(_) => false,
},
token::OpenDelim(Delimiter::Invisible(InvisibleOrigin::MetaVar(k))) => match k {
MetaVarKind::Block
| MetaVarKind::Stmt
| MetaVarKind::Expr { .. }
| MetaVarKind::Literal => true,
MetaVarKind::Item
| MetaVarKind::Pat(_)
| MetaVarKind::Ty
| MetaVarKind::Meta
| MetaVarKind::Path
| MetaVarKind::Vis => false,
MetaVarKind::Lifetime | MetaVarKind::Ident | MetaVarKind::TT => {
unreachable!()
}
},
_ => false,
},
NonterminalKind::Path | NonterminalKind::Meta => match &token.kind {
token::PathSep | token::Ident(..) | token::NtIdent(..) => true,
token::Interpolated(nt) => may_be_ident(nt),
token::Interpolated(nt) => nt_may_be_ident(nt),
token::OpenDelim(Delimiter::Invisible(InvisibleOrigin::MetaVar(kind))) => {
may_be_ident(*kind)
}
_ => false,
},
NonterminalKind::Pat(pat_kind) => token.can_begin_pattern(pat_kind),