diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/expr.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/expr.rs | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index 192e87b4c01..26284728ff2 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -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); } |