bjoernager/rust
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Implement &pin const self and &pin mut self sugars

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This commit is contained in:
Frank King 2025-01-19 23:30:58 +08:00
parent 4559163ccb
commit cb7d687e96
10 changed files with 304 additions and 13 deletions
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45
compiler/rustc_parse/src/parser/item.rs
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@ -2959,9 +2959,20 @@ impl<'a> Parser<'a> {
this.is_keyword_ahead(n, &[kw::SelfLower])
&& this.look_ahead(n + 1, |t| t != &token::PathSep)
};
// Is `pin const self` `n` tokens ahead?
let is_isolated_pin_const_self = |this: &Self, n| {
this.look_ahead(n, |token| token.is_ident_named(sym::pin))
&& this.is_keyword_ahead(n + 1, &[kw::Const])
&& is_isolated_self(this, n + 2)
};
// Is `mut self` `n` tokens ahead?
let is_isolated_mut_self =
|this: &Self, n| this.is_keyword_ahead(n, &[kw::Mut]) && is_isolated_self(this, n + 1);
// Is `pin mut self` `n` tokens ahead?
let is_isolated_pin_mut_self = |this: &Self, n| {
this.look_ahead(n, |token| token.is_ident_named(sym::pin))
&& is_isolated_mut_self(this, n + 1)
};
// Parse `self` or `self: TYPE`. We already know the current token is `self`.
let parse_self_possibly_typed = |this: &mut Self, m| {
let eself_ident = expect_self_ident(this);
@ -3021,6 +3032,20 @@ impl<'a> Parser<'a> {
self.bump();
self.bump();
SelfKind::Region(None, Mutability::Mut)
} else if is_isolated_pin_const_self(self, 1) {
// `&pin const self`
self.bump(); // &
self.psess.gated_spans.gate(sym::pin_ergonomics, self.token.span);
self.bump(); // pin
self.bump(); // const
SelfKind::Pinned(None, Mutability::Not)
} else if is_isolated_pin_mut_self(self, 1) {
// `&pin mut self`
self.bump(); // &
self.psess.gated_spans.gate(sym::pin_ergonomics, self.token.span);
self.bump(); // pin
self.bump(); // mut
SelfKind::Pinned(None, Mutability::Mut)
} else if self.look_ahead(1, |t| t.is_lifetime()) && is_isolated_self(self, 2) {
// `&'lt self`
self.bump();
@ -3032,6 +3057,26 @@ impl<'a> Parser<'a> {
let lt = self.expect_lifetime();
self.bump();
SelfKind::Region(Some(lt), Mutability::Mut)
} else if self.look_ahead(1, |t| t.is_lifetime())
&& is_isolated_pin_const_self(self, 2)
{
// `&'lt pin const self`
self.bump(); // &
let lt = self.expect_lifetime();
self.psess.gated_spans.gate(sym::pin_ergonomics, self.token.span);
self.bump(); // pin
self.bump(); // const
SelfKind::Pinned(Some(lt), Mutability::Not)
} else if self.look_ahead(1, |t| t.is_lifetime())
&& is_isolated_pin_mut_self(self, 2)
{
// `&'lt pin mut self`
self.bump(); // &
let lt = self.expect_lifetime();
self.psess.gated_spans.gate(sym::pin_ergonomics, self.token.span);
self.bump(); // pin
self.bump(); // mut
SelfKind::Pinned(Some(lt), Mutability::Mut)
} else {
// `&not_self`
return Ok(None);