Ensure stack before parsing dot-or-call

There are many cases where, due to codegen or a massively unruly codebase,
a deeply nested call(call(call(call(call(call(call(call(call(f())))))))))
can happen. This is a spot where it would be good to grow our stack, so that
we can survive to tell the programmer their code is dubiously written.

Author: workingjubilee

compiler/rustc_parse/src/parser/expr.rs

@@ -943,7 +943,10 @@ impl<'a> Parser<'a> {
         // Stitch the list of outer attributes onto the return value.
         // A little bit ugly, but the best way given the current code
         // structure
-        let res = self.parse_expr_dot_or_call_with_(e0, lo);
+        let res = ensure_sufficient_stack(
+            // this expr demonstrates the recursion it guards against
+            || self.parse_expr_dot_or_call_with_(e0, lo),
+        );
         if attrs.is_empty() {
             res
         } else {