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Fix let_chains and if_let_guard feature flags

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This commit is contained in:
Caio 2022-01-22 17:45:45 -03:00
parent ecf72996ed
commit cbb0fffe59
5 changed files with 112 additions and 23 deletions
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20
compiler/rustc_parse/src/parser/expr.rs
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@ -2383,6 +2383,17 @@ impl<'a> Parser<'a> {
}
pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
fn check_let_expr(expr: &Expr) -> (bool, bool) {
match expr.kind {
ExprKind::Binary(_, ref lhs, ref rhs) => {
let lhs_rslt = check_let_expr(lhs);
let rhs_rslt = check_let_expr(rhs);
(lhs_rslt.0 || rhs_rslt.0, false)
}
ExprKind::Let(..) => (true, true),
_ => (false, true),
}
}
let attrs = self.parse_outer_attributes()?;
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
let lo = this.token.span;
@ -2390,9 +2401,12 @@ impl<'a> Parser<'a> {
let guard = if this.eat_keyword(kw::If) {
let if_span = this.prev_token.span;
let cond = this.parse_expr()?;
if let ExprKind::Let(..) = cond.kind {
// Remove the last feature gating of a `let` expression since it's stable.
this.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
let (has_let_expr, does_not_have_bin_op) = check_let_expr(&cond);
if has_let_expr {
if does_not_have_bin_op {
// Remove the last feature gating of a `let` expression since it's stable.
this.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
}
let span = if_span.to(cond.span);
this.sess.gated_spans.gate(sym::if_let_guard, span);
}