Rollup merge of rust-lang#72941 - nagisa:ensure-stack-for-match, r=ol…

…i-obk

Ensure stack when building MIR for matches

In particular matching on complex types such as strings will cause
deep recursion to happen.

Fixes rust-lang#72933

r? @matthewjasper @oli-obk

src/librustc_mir_build/build/matches/mod.rs

@@ -10,7 +10,7 @@ use crate::build::ForGuard::{self, OutsideGuard, RefWithinGuard};
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
 use crate::build::{GuardFrame, GuardFrameLocal, LocalsForNode};
 use crate::hair::{self, *};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::{fx::{FxHashMap, FxHashSet}, stack::ensure_sufficient_stack};
 use rustc_hir::HirId;
 use rustc_index::bit_set::BitSet;
 use rustc_middle::middle::region;
@@ -909,30 +909,32 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
  split_or_candidate |= self.simplify_candidate(candidate);
  }
 
- if split_or_candidate {
- // At least one of the candidates has been split into subcandidates.
- // We need to change the candidate list to include those.
- let mut new_candidates = Vec::new();
+ ensure_sufficient_stack(|| {
+ if split_or_candidate {
+ // At least one of the candidates has been split into subcandidates.
+ // We need to change the candidate list to include those.
+ let mut new_candidates = Vec::new();
 
- for candidate in candidates {
- candidate.visit_leaves(|leaf_candidate| new_candidates.push(leaf_candidate));
+ for candidate in candidates {
+ candidate.visit_leaves(|leaf_candidate| new_candidates.push(leaf_candidate));
+ }
+ self.match_simplified_candidates(
+ span,
+ start_block,
+ otherwise_block,
+ &mut *new_candidates,
+ fake_borrows,
+ );
+ } else {
+ self.match_simplified_candidates(
+ span,
+ start_block,
+ otherwise_block,
+ candidates,
+ fake_borrows,
+ );
  }
- self.match_simplified_candidates(
- span,
- start_block,
- otherwise_block,
- &mut *new_candidates,
- fake_borrows,
- );
- } else {
- self.match_simplified_candidates(
- span,
- start_block,
- otherwise_block,
- candidates,
- fake_borrows,
- );
- };
+ });
  }
 
  fn match_simplified_candidates(