Account for UnOps in borrowck message

Author: estebank

compiler/rustc_borrowck/messages.ftl

@@ -16,6 +16,9 @@ borrowck_borrow_due_to_use_closure =
 borrowck_borrow_due_to_use_coroutine =
     borrow occurs due to use in coroutine
 
+borrowck_calling_operator_moves =
+    calling this operator moves the value
+
 borrowck_calling_operator_moves_lhs =
     calling this operator moves the left-hand side
 

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -1050,7 +1050,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     );
                     err.subdiagnostic(self.dcx(), CaptureReasonNote::FnOnceMoveInCall { var_span });
                 }
-                CallKind::Operator { self_arg, .. } => {
+                CallKind::Operator { self_arg, trait_id, .. } => {
                     let self_arg = self_arg.unwrap();
                     err.subdiagnostic(
                         self.dcx(),
@@ -1062,9 +1062,16 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         },
                     );
                     if self.fn_self_span_reported.insert(fn_span) {
+                        let lang = self.infcx.tcx.lang_items();
                         err.subdiagnostic(
                             self.dcx(),
-                            CaptureReasonNote::LhsMoveByOperator { span: self_arg.span },
+                            if [lang.not_trait(), lang.deref_trait(), lang.neg_trait()]
+                                .contains(&Some(trait_id))
+                            {
+                                CaptureReasonNote::UnOpMoveByOperator { span: self_arg.span }
+                            } else {
+                                CaptureReasonNote::LhsMoveByOperator { span: self_arg.span }
+                            },
                         );
                     }
                 }

compiler/rustc_borrowck/src/session_diagnostics.rs

@@ -368,6 +368,11 @@ pub(crate) enum CaptureReasonNote {
         #[primary_span]
         var_span: Span,
     },
+    #[note(borrowck_calling_operator_moves)]
+    UnOpMoveByOperator {
+        #[primary_span]
+        span: Span,
+    },
     #[note(borrowck_calling_operator_moves_lhs)]
     LhsMoveByOperator {
         #[primary_span]

tests/ui/unop-move-semantics.stderr

@@ -9,7 +9,7 @@ LL |
 LL |     x.clone();
    |     ^ value borrowed here after move
    |
-note: calling this operator moves the left-hand side
+note: calling this operator moves the value
   --> $SRC_DIR/core/src/ops/bit.rs:LL:COL
 help: consider cloning the value if the performance cost is acceptable
    |
@@ -57,7 +57,7 @@ LL |     !*m;
    |     |move occurs because `*m` has type `T`, which does not implement the `Copy` trait
    |     `*m` moved due to usage in operator
    |
-note: calling this operator moves the left-hand side
+note: calling this operator moves the value
   --> $SRC_DIR/core/src/ops/bit.rs:LL:COL
 
 error[E0507]: cannot move out of `*n` which is behind a shared reference