Rollup merge of #101431 - compiler-errors:move-place-ty-for-move-place-sugg, r=cjgillot

Look at move place's type when suggesting mutable reborrow

Not sure why we are looking at the use site's ty instead of the move site's ty in order to suggest reborrowing the move site, but it was suppressing a perfectly valid reborrow suggestion.

r? `@estebank` who i think touched this last in 520461f1fb, though that was quite a while ago so feel free to reassign.

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -198,7 +198,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     move_span,
                     move_spans,
                     *moved_place,
-                    Some(used_place),
                     partially_str,
                     loop_message,
                     move_msg,

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -972,7 +972,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         move_span: Span,
         move_spans: UseSpans<'tcx>,
         moved_place: Place<'tcx>,
-        used_place: Option<PlaceRef<'tcx>>,
         partially_str: &str,
         loop_message: &str,
         move_msg: &str,
@@ -1060,9 +1059,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 place_name, partially_str, loop_message
                             ),
                         );
-                        // If we have a `&mut` ref, we need to reborrow.
-                        if let Some(ty::Ref(_, _, hir::Mutability::Mut)) = used_place
-                            .map(|used_place| used_place.ty(self.body, self.infcx.tcx).ty.kind())
+                        // If the moved place was a `&mut` ref, then we can
+                        // suggest to reborrow it where it was moved, so it
+                        // will still be valid by the time we get to the usage.
+                        if let ty::Ref(_, _, hir::Mutability::Mut) =
+                            moved_place.ty(self.body, self.infcx.tcx).ty.kind()
                         {
                             // If we are in a loop this will be suggested later.
                             if !is_loop_move {

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -401,7 +401,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         };
         if let Some(use_spans) = use_spans {
             self.explain_captures(
-                &mut err, span, span, use_spans, move_place, None, "", "", "", false, true,
+                &mut err, span, span, use_spans, move_place, "", "", "", false, true,
             );
         }
         err