Remove unused helper function

Author: ecstatic-morse

compiler/rustc_mir/src/dataflow/drop_flag_effects.rs

@@ -1,7 +1,6 @@
 use crate::util::elaborate_drops::DropFlagState;
 use rustc_middle::mir::{self, Body, Location};
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_target::abi::VariantIdx;
 
 use super::indexes::MovePathIndex;
 use super::move_paths::{InitKind, LookupResult, MoveData};
@@ -229,42 +228,3 @@ pub(crate) fn for_location_inits<'tcx, F>(
         }
     }
 }
-
-/// Calls `handle_inactive_variant` for each descendant move path of `enum_place` that contains a
-/// `Downcast` to a variant besides the `active_variant`.
-///
-/// NOTE: If there are no move paths corresponding to an inactive variant,
-/// `handle_inactive_variant` will not be called for that variant.
-pub(crate) fn on_all_inactive_variants<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    body: &mir::Body<'tcx>,
-    move_data: &MoveData<'tcx>,
-    enum_place: mir::Place<'tcx>,
-    active_variant: VariantIdx,
-    mut handle_inactive_variant: impl FnMut(MovePathIndex),
-) {
-    let enum_mpi = match move_data.rev_lookup.find(enum_place.as_ref()) {
-        LookupResult::Exact(mpi) => mpi,
-        LookupResult::Parent(_) => return,
-    };
-
-    let enum_path = &move_data.move_paths[enum_mpi];
-    for (variant_mpi, variant_path) in enum_path.children(&move_data.move_paths) {
-        // Because of the way we build the `MoveData` tree, each child should have exactly one more
-        // projection than `enum_place`. This additional projection must be a downcast since the
-        // base is an enum.
-        let (downcast, base_proj) = variant_path.place.projection.split_last().unwrap();
-        assert_eq!(enum_place.projection.len(), base_proj.len());
-
-        let variant_idx = match *downcast {
-            mir::ProjectionElem::Downcast(_, idx) => idx,
-            _ => unreachable!(),
-        };
-
-        if variant_idx != active_variant {
-            on_all_children_bits(tcx, body, move_data, variant_mpi, |mpi| {
-                handle_inactive_variant(mpi)
-            });
-        }
-    }
-}