Add a flag enabling drop range tracking in generators

Author: tmiasko

compiler/rustc_interface/src/tests.rs

@@ -730,6 +730,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(debug_info_for_profiling, true);
     tracked!(debug_macros, true);
     tracked!(dep_info_omit_d_target, true);
+    tracked!(drop_tracking, true);
     tracked!(dual_proc_macros, true);
     tracked!(fewer_names, Some(true));
     tracked!(force_unstable_if_unmarked, true);

compiler/rustc_session/src/options.rs

@@ -1173,6 +1173,8 @@ options! {
     dont_buffer_diagnostics: bool = (false, parse_bool, [UNTRACKED],
         "emit diagnostics rather than buffering (breaks NLL error downgrading, sorting) \
         (default: no)"),
+    drop_tracking: bool = (false, parse_bool, [TRACKED],
+        "enables drop tracking in generators (default: no)"),
     dual_proc_macros: bool = (false, parse_bool, [TRACKED],
         "load proc macros for both target and host, but only link to the target (default: no)"),
     dump_dep_graph: bool = (false, parse_bool, [UNTRACKED],

compiler/rustc_typeck/src/check/generator_interior.rs

@@ -22,11 +22,6 @@ use tracing::debug;
 
 mod drop_ranges;
 
-// FIXME(eholk): This flag is here to give a quick way to disable drop tracking in case we find
-// unexpected breakages while it's still new. It should be removed before too long. For example,
-// see #93161.
-const ENABLE_DROP_TRACKING: bool = false;
-
 struct InteriorVisitor<'a, 'tcx> {
     fcx: &'a FnCtxt<'a, 'tcx>,
     types: FxIndexSet<ty::GeneratorInteriorTypeCause<'tcx>>,
@@ -82,7 +77,7 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> {
                                 yield_data.expr_and_pat_count, self.expr_count, source_span
                             );
 
-                            if ENABLE_DROP_TRACKING
+                            if self.fcx.sess().opts.debugging_opts.drop_tracking
                                 && self
                                     .drop_ranges
                                     .is_dropped_at(hir_id, yield_data.expr_and_pat_count)

compiler/rustc_typeck/src/check/generator_interior/drop_ranges.rs

@@ -37,7 +37,7 @@ pub fn compute_drop_ranges<'a, 'tcx>(
     def_id: DefId,
     body: &'tcx Body<'tcx>,
 ) -> DropRanges {
-    if super::ENABLE_DROP_TRACKING {
+    if fcx.sess().opts.debugging_opts.drop_tracking {
         let consumed_borrowed_places = find_consumed_and_borrowed(fcx, def_id, body);
 
         let num_exprs = fcx.tcx.region_scope_tree(def_id).body_expr_count(body.id()).unwrap_or(0);