Hmm having trouble finding the bisect, but this at least would work

Author: stephen-lazaro

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -682,7 +682,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
         for init_idx in inits {
             let init = &self.move_data.inits[*init_idx];
             let span = init.span(self.body);
-            if !span.is_dummy() {
+            if !span.is_dummy() && !spans.contains(&span) {
                 spans.push(span);
             }
         }
@@ -779,7 +779,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
             }
         }
         if !shown {
-            spans.dedup();
             for sp in &spans {
                 if *sp < span && !sp.overlaps(span) {
                     err.span_label(*sp, "binding initialized here in some conditions");