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Unrolled build for rust-lang#126571
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Rollup merge of rust-lang#126571 - nnethercote:less-maybe_whole-expr-2, r=petrochenkov

Less `maybe_whole_expr`, take 2

I first tried this in rust-lang#107550. I now think it's worth doing again, as a precursor to rust-lang#124141.

r? ```@petrochenkov```
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rust-timer authored Jun 27, 2024
2 parents 536235f + 379b761 commit 1c32639
Showing 1 changed file with 41 additions and 32 deletions.
73 changes: 41 additions & 32 deletions compiler/rustc_parse/src/parser/expr.rs
Original file line number Diff line number Diff line change
Expand Up @@ -39,36 +39,6 @@ use rustc_span::{BytePos, ErrorGuaranteed, Pos, Span};
use thin_vec::{thin_vec, ThinVec};
use tracing::instrument;

/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
/// dropped into the token stream, which happens while parsing the result of
/// macro expansion). Placement of these is not as complex as I feared it would
/// be. The important thing is to make sure that lookahead doesn't balk at
/// `token::Interpolated` tokens.
macro_rules! maybe_whole_expr {
($p:expr) => {
if let token::Interpolated(nt) = &$p.token.kind {
match &**nt {
token::NtExpr(e) | token::NtLiteral(e) => {
let e = e.clone();
$p.bump();
return Ok(e);
}
token::NtPath(path) => {
let path = (**path).clone();
$p.bump();
return Ok($p.mk_expr($p.prev_token.span, ExprKind::Path(None, path)));
}
token::NtBlock(block) => {
let block = block.clone();
$p.bump();
return Ok($p.mk_expr($p.prev_token.span, ExprKind::Block(block, None)));
}
_ => {}
};
}
};
}

#[derive(Debug)]
pub(super) enum LhsExpr {
// Already parsed just the outer attributes.
Expand Down Expand Up @@ -1421,7 +1391,27 @@ impl<'a> Parser<'a> {
/// correctly if called from `parse_dot_or_call_expr()`.
fn parse_expr_bottom(&mut self) -> PResult<'a, P<Expr>> {
maybe_recover_from_interpolated_ty_qpath!(self, true);
maybe_whole_expr!(self);

if let token::Interpolated(nt) = &self.token.kind {
match &**nt {
token::NtExpr(e) | token::NtLiteral(e) => {
let e = e.clone();
self.bump();
return Ok(e);
}
token::NtPath(path) => {
let path = (**path).clone();
self.bump();
return Ok(self.mk_expr(self.prev_token.span, ExprKind::Path(None, path)));
}
token::NtBlock(block) => {
let block = block.clone();
self.bump();
return Ok(self.mk_expr(self.prev_token.span, ExprKind::Block(block, None)));
}
_ => {}
};
}

// Outer attributes are already parsed and will be
// added to the return value after the fact.
Expand Down Expand Up @@ -2190,7 +2180,26 @@ impl<'a> Parser<'a> {
/// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
/// Keep this in sync with `Token::can_begin_literal_maybe_minus`.
pub fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
maybe_whole_expr!(self);
if let token::Interpolated(nt) = &self.token.kind {
match &**nt {
// FIXME(nnethercote) The `NtExpr` case should only match if
// `e` is an `ExprKind::Lit` or an `ExprKind::Unary` containing
// an `UnOp::Neg` and an `ExprKind::Lit`, like how
// `can_begin_literal_maybe_minus` works. But this method has
// been over-accepting for a long time, and to make that change
// here requires also changing some `parse_literal_maybe_minus`
// call sites to accept additional expression kinds. E.g.
// `ExprKind::Path` must be accepted when parsing range
// patterns. That requires some care. So for now, we continue
// being less strict here than we should be.
token::NtExpr(e) | token::NtLiteral(e) => {
let e = e.clone();
self.bump();
return Ok(e);
}
_ => {}
};
}

let lo = self.token.span;
let minus_present = self.eat(&token::BinOp(token::Minus));
Expand Down

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