Fix a stack overflow with long else if chains

1 files changed, 2 insertions, 1 deletions

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index e308e5b3420..9ae3ef6172c 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -22,6 +22,7 @@ use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty
 use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
 use rustc_ast::{ClosureBinder, MetaItemLit, StmtKind};
 use rustc_ast_pretty::pprust;
+use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{
     AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic,
     PResult, StashKey,
@@ -2489,7 +2490,7 @@ impl<'a> Parser<'a> {
         let else_span = self.prev_token.span; // `else`
         let attrs = self.parse_outer_attributes()?; // For recovery.
         let expr = if self.eat_keyword(kw::If) {
-            self.parse_expr_if()?
+            ensure_sufficient_stack(|| self.parse_expr_if())?
         } else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
             self.parse_simple_block()?
         } else {