bjoernager/rust
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Syntatically accept become expressions

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This commit is contained in:
Maybe Waffle 2022-11-16 18:36:17 +00:00
parent 8d1fa473dd
commit d7713feb99
14 changed files with 71 additions and 2 deletions
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12
compiler/rustc_parse/src/parser/expr.rs
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@ -1430,6 +1430,8 @@ impl<'a> Parser<'a> {
self.parse_expr_yield()
} else if self.is_do_yeet() {
self.parse_expr_yeet()
} else if self.eat_keyword(kw::Become) {
self.parse_expr_become()
} else if self.check_keyword(kw::Let) {
self.parse_expr_let()
} else if self.eat_keyword(kw::Underscore) {
@ -1746,6 +1748,16 @@ impl<'a> Parser<'a> {
self.maybe_recover_from_bad_qpath(expr)
}
/// Parse `"become" expr`, with `"become"` token already eaten.
fn parse_expr_become(&mut self) -> PResult<'a, P<Expr>> {
let lo = self.prev_token.span;
let kind = ExprKind::Become(self.parse_expr()?);
let span = lo.to(self.prev_token.span);
self.sess.gated_spans.gate(sym::explicit_tail_calls, span);
let expr = self.mk_expr(span, kind);
self.maybe_recover_from_bad_qpath(expr)
}
/// Parse `"break" (('label (:? expr)?) | expr?)` with `"break"` token already eaten.
/// If the label is followed immediately by a `:` token, the label and `:` are
/// parsed as part of the expression (i.e. a labeled loop). The language team has