Verify receiver is of self: Pin<&mut Self>

Author: estebank

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -1132,9 +1132,13 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 place_name, partially_str, loop_message
                             ),
                         );
-                        let ty = moved_place.ty(self.body, self.infcx.tcx).ty;
-                        if let ty::Adt(def, ..) = ty.kind()
+                        let ty = tcx.erase_regions(moved_place.ty(self.body, self.infcx.tcx).ty);
+                        if let ty::Adt(def, substs) = ty.kind()
                             && Some(def.did()) == self.infcx.tcx.lang_items().pin_type()
+                            && let ty::Ref(_, _, hir::Mutability::Mut) = substs.type_at(0).kind()
+                            // FIXME: this is a hack because we can't call `can_eq`
+                            && ty.to_string() ==    
+                                tcx.fn_sig(method_did).input(0).skip_binder().to_string()
                         {
                             err.span_suggestion_verbose(
                                 fn_call_span.shrink_to_lo(),

src/test/ui/moves/move-fn-self-receiver.stderr

@@ -67,10 +67,6 @@ note: `Foo::use_pin_box_self` takes ownership of the receiver `self`, which move
    |
 LL |     fn use_pin_box_self(self: Pin<Box<Self>>) {}
    |                         ^^^^
-help: consider reborrowing the `Pin` instead of moving it
-   |
-LL |     pin_box_foo.as_mut().use_pin_box_self();
-   |                 +++++++++
 
 error[E0505]: cannot move out of `mut_foo` because it is borrowed
   --> $DIR/move-fn-self-receiver.rs:50:5