Auto merge of rust-lang#75302 - Aaron1011:feature/partial-move-diag, r=estebank

Be consistent when describing a move as a 'partial' in diagnostics

When an error occurs due to a partial move, we would use the world
"partial" in some parts of the error message, but not in others. This
commit ensures that we use the word 'partial' in either all or none of
the diagnostic messages.

Additionally, we no longer describe a move out of a `Box` via `*` as
a 'partial move'. This was a pre-existing issue, but became more
noticable when the word 'partial' is used in more places.

Author: bors

src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs

@@ -113,23 +113,32 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 }
             }
 
-            let msg = ""; //FIXME: add "partially " or "collaterally "
+            let is_partial_move = move_site_vec.iter().any(|move_site| {
+                let move_out = self.move_data.moves[(*move_site).moi];
+                let moved_place = &self.move_data.move_paths[move_out.path].place;
+                // `*(_1)` where `_1` is a `Box` is actually a move out.
+                let is_box_move = moved_place.as_ref().projection == &[ProjectionElem::Deref]
+                    && self.body.local_decls[moved_place.local].ty.is_box();
+
+                !is_box_move
+                    && used_place != moved_place.as_ref()
+                    && used_place.is_prefix_of(moved_place.as_ref())
+            });
+
+            let partial_str = if is_partial_move { "partial " } else { "" };
+            let partially_str = if is_partial_move { "partially " } else { "" };
 
             let mut err = self.cannot_act_on_moved_value(
                 span,
                 desired_action.as_noun(),
-                msg,
+                partially_str,
                 self.describe_place_with_options(moved_place, IncludingDowncast(true)),
             );
 
             self.add_moved_or_invoked_closure_note(location, used_place, &mut err);
 
             let mut is_loop_move = false;
-            let is_partial_move = move_site_vec.iter().any(|move_site| {
-                let move_out = self.move_data.moves[(*move_site).moi];
-                let moved_place = &self.move_data.move_paths[move_out.path].place;
-                used_place != moved_place.as_ref() && used_place.is_prefix_of(moved_place.as_ref())
-            });
+
             for move_site in &move_site_vec {
                 let move_out = self.move_data.moves[(*move_site).moi];
                 let moved_place = &self.move_data.move_paths[move_out.path].place;
@@ -142,13 +151,19 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 if location == move_out.source {
                     err.span_label(
                         span,
-                        format!("value moved{} here, in previous iteration of loop", move_msg),
+                        format!(
+                            "value {}moved{} here, in previous iteration of loop",
+                            partially_str, move_msg
+                        ),
                     );
                     is_loop_move = true;
                 } else if move_site.traversed_back_edge {
                     err.span_label(
                         move_span,
-                        format!("value moved{} here, in previous iteration of loop", move_msg),
+                        format!(
+                            "value {}moved{} here, in previous iteration of loop",
+                            partially_str, move_msg
+                        ),
                     );
                 } else {
                     if let UseSpans::FnSelfUse { var_span, fn_call_span, fn_span, kind } =
@@ -162,7 +177,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             FnSelfUseKind::FnOnceCall => {
                                 err.span_label(
                                     fn_call_span,
-                                    &format!("{} moved due to this call", place_name),
+                                    &format!(
+                                        "{} {}moved due to this call",
+                                        place_name, partially_str
+                                    ),
                                 );
                                 err.span_note(
                                     var_span,
@@ -172,7 +190,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             FnSelfUseKind::Operator { self_arg } => {
                                 err.span_label(
                                     fn_call_span,
-                                    &format!("{} moved due to usage in operator", place_name),
+                                    &format!(
+                                        "{} {}moved due to usage in operator",
+                                        place_name, partially_str
+                                    ),
                                 );
                                 if self.fn_self_span_reported.insert(fn_span) {
                                     err.span_note(
@@ -186,14 +207,17 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                     err.span_label(
                                         fn_call_span,
                                         &format!(
-                                            "{} moved due to this implicit call to `.into_iter()`",
-                                            place_name
+                                            "{} {}moved due to this implicit call to `.into_iter()`",
+                                            place_name, partially_str
                                         ),
                                     );
                                 } else {
                                     err.span_label(
                                         fn_call_span,
-                                        &format!("{} moved due to this method call", place_name),
+                                        &format!(
+                                            "{} {}moved due to this method call",
+                                            place_name, partially_str
+                                        ),
                                     );
                                 }
                                 // Avoid pointing to the same function in multiple different
@@ -207,10 +231,17 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             }
                         }
                     } else {
-                        err.span_label(move_span, format!("value moved{} here", move_msg));
+                        err.span_label(
+                            move_span,
+                            format!("value {}moved{} here", partially_str, move_msg),
+                        );
                         move_spans.var_span_label(
                             &mut err,
-                            format!("variable moved due to use{}", move_spans.describe()),
+                            format!(
+                                "variable {}moved due to use{}",
+                                partially_str,
+                                move_spans.describe()
+                            ),
                         );
                     }
                 }
@@ -250,9 +281,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 err.span_label(
                     span,
                     format!(
-                        "value {} here {}",
+                        "value {} here after {}move",
                         desired_action.as_verb_in_past_tense(),
-                        if is_partial_move { "after partial move" } else { "after move" },
+                        partial_str
                     ),
                 );
             }
@@ -321,7 +352,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 } else {
                     None
                 };
-                self.note_type_does_not_implement_copy(&mut err, &note_msg, ty, span);
+                self.note_type_does_not_implement_copy(&mut err, &note_msg, ty, span, partial_str);
             }
 
             if let Some((_, mut old_err)) =
@@ -1398,8 +1429,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
                 for moi in &self.move_data.loc_map[location] {
                     debug!("report_use_of_moved_or_uninitialized: moi={:?}", moi);
-                    if mpis.contains(&self.move_data.moves[*moi].path) {
-                        debug!("report_use_of_moved_or_uninitialized: found");
+                    let path = self.move_data.moves[*moi].path;
+                    if mpis.contains(&path) {
+                        debug!(
+                            "report_use_of_moved_or_uninitialized: found {:?}",
+                            move_paths[path].place
+                        );
                         result.push(MoveSite { moi: *moi, traversed_back_edge: is_back_edge });
 
                         // Strictly speaking, we could continue our DFS here. There may be

src/librustc_mir/borrow_check/diagnostics/mod.rs

@@ -412,10 +412,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         place_desc: &str,
         ty: Ty<'tcx>,
         span: Option<Span>,
+        move_prefix: &str,
     ) {
         let message = format!(
-            "move occurs because {} has type `{}`, which does not implement the `Copy` trait",
-            place_desc, ty,
+            "{}move occurs because {} has type `{}`, which does not implement the `Copy` trait",
+            move_prefix, place_desc, ty,
         );
         if let Some(span) = span {
             err.span_label(span, message);

src/librustc_mir/borrow_check/diagnostics/move_errors.rs

@@ -445,7 +445,13 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         None => "value".to_string(),
                     };
 
-                    self.note_type_does_not_implement_copy(err, &place_desc, place_ty, Some(span));
+                    self.note_type_does_not_implement_copy(
+                        err,
+                        &place_desc,
+                        place_ty,
+                        Some(span),
+                        "",
+                    );
                 } else {
                     binds_to.sort();
                     binds_to.dedup();
@@ -467,7 +473,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     Some(desc) => format!("`{}`", desc),
                     None => "value".to_string(),
                 };
-                self.note_type_does_not_implement_copy(err, &place_desc, place_ty, Some(span));
+                self.note_type_does_not_implement_copy(err, &place_desc, place_ty, Some(span), "");
 
                 use_spans.args_span_label(err, format!("move out of {} occurs here", place_desc));
                 use_spans
@@ -529,6 +535,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     &format!("`{}`", self.local_names[*local].unwrap()),
                     bind_to.ty,
                     Some(binding_span),
+                    "",
                 );
             }
         }

src/test/ui/async-await/issues/issue-66958-non-copy-infered-type-arg.rs

@@ -8,7 +8,7 @@ impl<S> Ia<S> {
 
     async fn crash(self) {
         Self::partial(self.0);
-        Self::full(self); //~ ERROR use of moved value: `self`
+        Self::full(self); //~ ERROR use of partially moved value: `self`
     }
 }
 

src/test/ui/async-await/issues/issue-66958-non-copy-infered-type-arg.stderr

@@ -1,12 +1,12 @@
-error[E0382]: use of moved value: `self`
+error[E0382]: use of partially moved value: `self`
   --> $DIR/issue-66958-non-copy-infered-type-arg.rs:11:20
    |
 LL |         Self::partial(self.0);
-   |                       ------ value moved here
+   |                       ------ value partially moved here
 LL |         Self::full(self);
    |                    ^^^^ value used here after partial move
    |
-   = note: move occurs because `self.0` has type `S`, which does not implement the `Copy` trait
+   = note: partial move occurs because `self.0` has type `S`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 

src/test/ui/binding/issue-53114-borrow-checks.stderr

@@ -8,26 +8,26 @@ LL |     drop(m);
 LL |     match m { _ => { } } // #53114: should eventually be accepted too
    |           ^ value used here after move
 
-error[E0382]: use of moved value: `mm`
+error[E0382]: use of partially moved value: `mm`
   --> $DIR/issue-53114-borrow-checks.rs:27:11
    |
 LL |     match mm { (_x, _) => { } }
-   |                 -- value moved here
+   |                 -- value partially moved here
 LL |     match mm { (_, _y) => { } }
    |           ^^ value used here after partial move
    |
-   = note: move occurs because `mm.0` has type `M`, which does not implement the `Copy` trait
+   = note: partial move occurs because `mm.0` has type `M`, which does not implement the `Copy` trait
 
-error[E0382]: use of moved value: `mm`
+error[E0382]: use of partially moved value: `mm`
   --> $DIR/issue-53114-borrow-checks.rs:29:11
    |
 LL |     match mm { (_, _y) => { } }
-   |                    -- value moved here
+   |                    -- value partially moved here
 LL |
 LL |     match mm { (_, _) => { } }
    |           ^^ value used here after partial move
    |
-   = note: move occurs because `mm.1` has type `M`, which does not implement the `Copy` trait
+   = note: partial move occurs because `mm.1` has type `M`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `m`
   --> $DIR/issue-53114-borrow-checks.rs:36:16
@@ -39,26 +39,26 @@ LL |     drop(m);
 LL |     if let _ = m { } // #53114: should eventually be accepted too
    |                ^ value used here after move
 
-error[E0382]: use of moved value: `mm`
+error[E0382]: use of partially moved value: `mm`
   --> $DIR/issue-53114-borrow-checks.rs:41:22
    |
 LL |     if let (_x, _) = mm { }
-   |             -- value moved here
+   |             -- value partially moved here
 LL |     if let (_, _y) = mm { }
    |                      ^^ value used here after partial move
    |
-   = note: move occurs because `mm.0` has type `M`, which does not implement the `Copy` trait
+   = note: partial move occurs because `mm.0` has type `M`, which does not implement the `Copy` trait
 
-error[E0382]: use of moved value: `mm`
+error[E0382]: use of partially moved value: `mm`
   --> $DIR/issue-53114-borrow-checks.rs:43:21
    |
 LL |     if let (_, _y) = mm { }
-   |                -- value moved here
+   |                -- value partially moved here
 LL |
 LL |     if let (_, _) = mm { }
    |                     ^^ value used here after partial move
    |
-   = note: move occurs because `mm.1` has type `M`, which does not implement the `Copy` trait
+   = note: partial move occurs because `mm.1` has type `M`, which does not implement the `Copy` trait
 
 error: aborting due to 6 previous errors
 

src/test/ui/borrowck/borrowck-move-out-from-array-match.rs

@@ -20,7 +20,7 @@ fn move_out_from_begin_field_and_end() {
         [_, _, (_x, _)] => {}
     }
     match a {
-        [.., _y] => {} //~ ERROR use of moved value
+        [.., _y] => {} //~ ERROR use of partially moved value
     }
 }
 
@@ -42,7 +42,7 @@ fn move_out_by_const_index_and_subslice() {
         [_x, _, _] => {}
     }
     match a {
-        //~^ ERROR use of moved value
+        //~^ ERROR use of partially moved value
         [_y @ .., _, _] => {}
     }
 }
@@ -53,7 +53,7 @@ fn move_out_by_const_index_end_and_subslice() {
         [.., _x] => {}
     }
     match a {
-        //~^ ERROR use of moved value
+        //~^ ERROR use of partially moved value
         [_, _, _y @ ..] => {}
     }
 }
@@ -64,7 +64,7 @@ fn move_out_by_const_index_field_and_subslice() {
         [(_x, _), _, _] => {}
     }
     match a {
-        //~^ ERROR use of moved value
+        //~^ ERROR use of partially moved value
         [_y @ .., _, _] => {}
     }
 }
@@ -75,7 +75,7 @@ fn move_out_by_const_index_end_field_and_subslice() {
         [.., (_x, _)] => {}
     }
     match a {
-        //~^ ERROR use of moved value
+        //~^ ERROR use of partially moved value
         [_, _, _y @ ..] => {}
     }
 }
@@ -108,7 +108,7 @@ fn move_out_by_subslice_and_subslice() {
         [x @ .., _] => {}
     }
     match a {
-        //~^ ERROR use of moved value
+        //~^ ERROR use of partially moved value
         [_, _y @ ..] => {}
     }
 }