Mention when the type of the moved value doesn't implement Clone

estebank · estebank · commit b7b114292073 · 2024-03-17T23:34:20.000Z
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -955,8 +955,19 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let ty = ty.peel_refs();
         if self.implements_clone(ty) {
             self.suggest_cloning_inner(err, ty, expr);
-            // } else {
-            //     err.note(format!("if `{ty}` implemented `Clone`, you could clone the value"));
+        } else if let ty::Adt(def, args) = ty.kind()
+            && def.did().as_local().is_some()
+            && def.variants().iter().all(|variant| {
+                variant
+                    .fields
+                    .iter()
+                    .all(|field| self.implements_clone(field.ty(self.infcx.tcx, args)))
+            })
+        {
+            err.span_note(
+                self.infcx.tcx.def_span(def.did()),
+                format!("if `{ty}` implemented `Clone`, you could clone the value"),
+            );
         }
     }
 
diff --git a/tests/ui/associated-types/issue-25700.stderr b/tests/ui/associated-types/issue-25700.stderr
@@ -7,6 +7,12 @@ LL |     drop(t);
    |          - value moved here
 LL |     drop(t);
    |          ^ value used here after move
+   |
+note: if `S<()>` implemented `Clone`, you could clone the value
+  --> $DIR/issue-25700.rs:1:1
+   |
+LL | struct S<T: 'static>(#[allow(dead_code)] Option<&'static T>);
+   | ^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-move-out-of-static-item.stderr b/tests/ui/borrowck/borrowck-move-out-of-static-item.stderr
@@ -3,6 +3,12 @@ error[E0507]: cannot move out of static item `BAR`
    |
 LL |     test(BAR);
    |          ^^^ move occurs because `BAR` has type `Foo`, which does not implement the `Copy` trait
+   |
+note: if `Foo` implemented `Clone`, you could clone the value
+  --> $DIR/borrowck-move-out-of-static-item.rs:3:1
+   |
+LL | struct Foo {
+   | ^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-move-subcomponent.stderr b/tests/ui/borrowck/borrowck-move-subcomponent.stderr
@@ -9,6 +9,12 @@ LL |   let S { x: ax } = a;
    |              ^^ move out of `a.x` occurs here
 LL |   f(pb);
    |     -- borrow later used here
+   |
+note: if `S` implemented `Clone`, you could clone the value
+  --> $DIR/borrowck-move-subcomponent.rs:6:1
+   |
+LL | struct S {
+   | ^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-overloaded-call.stderr b/tests/ui/borrowck/borrowck-overloaded-call.stderr
@@ -29,6 +29,12 @@ LL |     s(" world".to_string());
    |     - value moved here
 LL |     s(" world".to_string());
    |     ^ value used here after move
+   |
+note: if `SFnOnce` implemented `Clone`, you could clone the value
+  --> $DIR/borrowck-overloaded-call.rs:41:1
+   |
+LL | struct SFnOnce {
+   | ^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/borrowck/clone-on-ref.stderr b/tests/ui/borrowck/clone-on-ref.stderr
@@ -52,6 +52,11 @@ LL |
 LL |     println!("{b:?}");
    |               ----- borrow later used here
    |
+note: if `A` implemented `Clone`, you could clone the value
+  --> $DIR/clone-on-ref.rs:19:1
+   |
+LL | struct A;
+   | ^^^^^^^^
 help: consider annotating `A` with `#[derive(Clone)]`
    |
 LL + #[derive(Clone)]
diff --git a/tests/ui/borrowck/issue-103624.stderr b/tests/ui/borrowck/issue-103624.stderr
@@ -9,6 +9,12 @@ LL |         spawn_blocking(move || {
 LL |
 LL |             self.b;
    |             ^^^^^^ move occurs because `self.b` has type `StructB`, which does not implement the `Copy` trait
+   |
+note: if `StructB` implemented `Clone`, you could clone the value
+  --> $DIR/issue-103624.rs:23:1
+   |
+LL | struct StructB {}
+   | ^^^^^^^^^^^^^^
 
 error[E0521]: borrowed data escapes outside of method
   --> $DIR/issue-103624.rs:14:9
diff --git a/tests/ui/borrowck/issue-119915-bad-clone-suggestion.stderr b/tests/ui/borrowck/issue-119915-bad-clone-suggestion.stderr
@@ -11,6 +11,11 @@ note: `Example::<E, FakeParam>::change` takes ownership of the receiver `self`,
    |
 LL |     unsafe fn change<NewFakeParam>(self) -> Example<E, NewFakeParam> {
    |                                    ^^^^
+note: if `Example<E, NoLifetime>` implemented `Clone`, you could clone the value
+  --> $DIR/issue-119915-bad-clone-suggestion.rs:3:1
+   |
+LL | struct Example<E, FakeParam>(PhantomData<(fn(E), fn(FakeParam))>);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/issue-17718-static-move.stderr b/tests/ui/borrowck/issue-17718-static-move.stderr
@@ -4,6 +4,11 @@ error[E0507]: cannot move out of static item `FOO`
 LL |     let _a = FOO;
    |              ^^^ move occurs because `FOO` has type `Foo`, which does not implement the `Copy` trait
    |
+note: if `Foo` implemented `Clone`, you could clone the value
+  --> $DIR/issue-17718-static-move.rs:1:1
+   |
+LL | struct Foo;
+   | ^^^^^^^^^^
 help: consider borrowing here
    |
 LL |     let _a = &FOO;
diff --git a/tests/ui/borrowck/issue-20801.stderr b/tests/ui/borrowck/issue-20801.stderr
@@ -19,6 +19,11 @@ error[E0507]: cannot move out of a mutable reference
 LL |     let a = unsafe { *mut_ref() };
    |                      ^^^^^^^^^^ move occurs because value has type `T`, which does not implement the `Copy` trait
    |
+note: if `T` implemented `Clone`, you could clone the value
+  --> $DIR/issue-20801.rs:3:1
+   |
+LL | struct T(u8);
+   | ^^^^^^^^
 help: consider removing the dereference here
    |
 LL -     let a = unsafe { *mut_ref() };
@@ -31,6 +36,11 @@ error[E0507]: cannot move out of a shared reference
 LL |     let b = unsafe { *imm_ref() };
    |                      ^^^^^^^^^^ move occurs because value has type `T`, which does not implement the `Copy` trait
    |
+note: if `T` implemented `Clone`, you could clone the value
+  --> $DIR/issue-20801.rs:3:1
+   |
+LL | struct T(u8);
+   | ^^^^^^^^
 help: consider removing the dereference here
    |
 LL -     let b = unsafe { *imm_ref() };
@@ -43,6 +53,11 @@ error[E0507]: cannot move out of a raw pointer
 LL |     let c = unsafe { *mut_ptr() };
    |                      ^^^^^^^^^^ move occurs because value has type `T`, which does not implement the `Copy` trait
    |
+note: if `T` implemented `Clone`, you could clone the value
+  --> $DIR/issue-20801.rs:3:1
+   |
+LL | struct T(u8);
+   | ^^^^^^^^
 help: consider removing the dereference here
    |
 LL -     let c = unsafe { *mut_ptr() };
@@ -55,6 +70,11 @@ error[E0507]: cannot move out of a raw pointer
 LL |     let d = unsafe { *const_ptr() };
    |                      ^^^^^^^^^^^^ move occurs because value has type `T`, which does not implement the `Copy` trait
    |
+note: if `T` implemented `Clone`, you could clone the value
+  --> $DIR/issue-20801.rs:3:1
+   |
+LL | struct T(u8);
+   | ^^^^^^^^
 help: consider removing the dereference here
    |
 LL -     let d = unsafe { *const_ptr() };
diff --git a/tests/ui/borrowck/move-error-in-promoted-2.stderr b/tests/ui/borrowck/move-error-in-promoted-2.stderr
@@ -6,6 +6,12 @@ LL |     &([S][0],);
    |       |
    |       cannot move out of here
    |       move occurs because value has type `S`, which does not implement the `Copy` trait
+   |
+note: if `S` implemented `Clone`, you could clone the value
+  --> $DIR/move-error-in-promoted-2.rs:3:1
+   |
+LL | struct S;
+   | ^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/move-error-snippets.stderr b/tests/ui/borrowck/move-error-snippets.stderr
@@ -9,6 +9,11 @@ LL |         let a = $c;
 LL | sss!();
    | ------ in this macro invocation
    |
+note: if `A` implemented `Clone`, you could clone the value
+  --> $DIR/move-error-snippets.rs:9:1
+   |
+LL | struct A;
+   | ^^^^^^^^
    = note: this error originates in the macro `aaa` which comes from the expansion of the macro `sss` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider borrowing here
    |
diff --git a/tests/ui/borrowck/move-in-static-initializer-issue-38520.stderr b/tests/ui/borrowck/move-in-static-initializer-issue-38520.stderr
@@ -3,12 +3,24 @@ error[E0507]: cannot move out of a shared reference
    |
 LL | static Y: usize = get(*&X);
    |                       ^^^ move occurs because value has type `Foo`, which does not implement the `Copy` trait
+   |
+note: if `Foo` implemented `Clone`, you could clone the value
+  --> $DIR/move-in-static-initializer-issue-38520.rs:5:1
+   |
+LL | struct Foo(usize);
+   | ^^^^^^^^^^
 
 error[E0507]: cannot move out of a shared reference
   --> $DIR/move-in-static-initializer-issue-38520.rs:13:22
    |
 LL | const Z: usize = get(*&X);
    |                      ^^^ move occurs because value has type `Foo`, which does not implement the `Copy` trait
+   |
+note: if `Foo` implemented `Clone`, you could clone the value
+  --> $DIR/move-in-static-initializer-issue-38520.rs:5:1
+   |
+LL | struct Foo(usize);
+   | ^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/box/leak-alloc.stderr b/tests/ui/box/leak-alloc.stderr
@@ -11,6 +11,12 @@ LL |     drop(alloc);
 LL |
 LL |     use_value(*theref)
    |               ------- borrow later used here
+   |
+note: if `Alloc` implemented `Clone`, you could clone the value
+  --> $DIR/leak-alloc.rs:8:1
+   |
+LL | struct Alloc {}
+   | ^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/derives/deriving-with-repr-packed.stderr b/tests/ui/derives/deriving-with-repr-packed.stderr
@@ -36,6 +36,11 @@ LL | #[repr(packed)]
 LL | struct X(Y);
    |          ^ move occurs because `self.0` has type `Y`, which does not implement the `Copy` trait
    |
+note: if `Y` implemented `Clone`, you could clone the value
+  --> $DIR/deriving-with-repr-packed.rs:16:1
+   |
+LL | struct Y(usize);
+   | ^^^^^^^^
    = note: `#[derive(Debug)]` triggers a move because taking references to the fields of a packed struct is undefined behaviour
    = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
diff --git a/tests/ui/error-codes/E0504.stderr b/tests/ui/error-codes/E0504.stderr
@@ -13,6 +13,12 @@ LL |         println!("child function: {}", fancy_num.num);
 ...
 LL |     println!("main function: {}", fancy_ref.num);
    |                                   ------------- borrow later used here
+   |
+note: if `FancyNum` implemented `Clone`, you could clone the value
+  --> $DIR/E0504.rs:1:1
+   |
+LL | struct FancyNum {
+   | ^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/error-codes/E0505.stderr b/tests/ui/error-codes/E0505.stderr
@@ -10,6 +10,12 @@ LL |         eat(x);
    |             ^ move out of `x` occurs here
 LL |         _ref_to_val.use_ref();
    |         ----------- borrow later used here
+   |
+note: if `Value` implemented `Clone`, you could clone the value
+  --> $DIR/E0505.rs:1:1
+   |
+LL | struct Value {}
+   | ^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/error-codes/E0507.stderr b/tests/ui/error-codes/E0507.stderr
@@ -11,6 +11,11 @@ note: `TheDarkKnight::nothing_is_true` takes ownership of the receiver `self`, w
    |
 LL |     fn nothing_is_true(self) {}
    |                        ^^^^
+note: if `TheDarkKnight` implemented `Clone`, you could clone the value
+  --> $DIR/E0507.rs:3:1
+   |
+LL | struct TheDarkKnight;
+   | ^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/error-codes/E0508-fail.stderr b/tests/ui/error-codes/E0508-fail.stderr
@@ -7,6 +7,11 @@ LL |     let _value = array[0];
    |                  cannot move out of here
    |                  move occurs because `array[_]` has type `NonCopy`, which does not implement the `Copy` trait
    |
+note: if `NonCopy` implemented `Clone`, you could clone the value
+  --> $DIR/E0508-fail.rs:1:1
+   |
+LL | struct NonCopy;
+   | ^^^^^^^^^^^^^^
 help: consider borrowing here
    |
 LL |     let _value = &array[0];
diff --git a/tests/ui/error-codes/E0508.stderr b/tests/ui/error-codes/E0508.stderr
@@ -7,6 +7,11 @@ LL |     let _value = array[0];
    |                  cannot move out of here
    |                  move occurs because `array[_]` has type `NonCopy`, which does not implement the `Copy` trait
    |
+note: if `NonCopy` implemented `Clone`, you could clone the value
+  --> $DIR/E0508.rs:1:1
+   |
+LL | struct NonCopy;
+   | ^^^^^^^^^^^^^^
 help: consider borrowing here
    |
 LL |     let _value = &array[0];
diff --git a/tests/ui/error-codes/E0509.stderr b/tests/ui/error-codes/E0509.stderr
@@ -7,6 +7,11 @@ LL |     let fancy_field = drop_struct.fancy;
    |                       cannot move out of here
    |                       move occurs because `drop_struct.fancy` has type `FancyNum`, which does not implement the `Copy` trait
    |
+note: if `FancyNum` implemented `Clone`, you could clone the value
+  --> $DIR/E0509.rs:1:1
+   |
+LL | struct FancyNum {
+   | ^^^^^^^^^^^^^^^
 help: consider borrowing here
    |
 LL |     let fancy_field = &drop_struct.fancy;
diff --git a/tests/ui/issues/issue-17385.stderr b/tests/ui/issues/issue-17385.stderr
@@ -7,6 +7,12 @@ LL |     drop(foo);
    |          --- value moved here
 LL |     match foo {
    |     ^^^^^^^^^ value used here after move
+   |
+note: if `X` implemented `Clone`, you could clone the value
+  --> $DIR/issue-17385.rs:1:1
+   |
+LL | struct X(isize);
+   | ^^^^^^^^
 
 error[E0382]: use of moved value: `e`
   --> $DIR/issue-17385.rs:25:11
@@ -17,6 +23,12 @@ LL |     drop(e);
    |          - value moved here
 LL |     match e {
    |           ^ value used here after move
+   |
+note: if `Enum` implemented `Clone`, you could clone the value
+  --> $DIR/issue-17385.rs:3:1
+   |
+LL | enum Enum {
+   | ^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/mir/issue-102389.stderr b/tests/ui/mir/issue-102389.stderr
@@ -3,6 +3,12 @@ error[E0507]: cannot move out of `*inbounds` which is behind a shared reference
    |
 LL |     array[*inbounds as usize]
    |           ^^^^^^^^^ move occurs because `*inbounds` has type `Enum`, which does not implement the `Copy` trait
+   |
+note: if `Enum` implemented `Clone`, you could clone the value
+  --> $DIR/issue-102389.rs:1:1
+   |
+LL | enum Enum { A, B, C }
+   | ^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/moves/issue-72649-uninit-in-loop.rs b/tests/ui/moves/issue-72649-uninit-in-loop.rs
@@ -3,6 +3,10 @@
 // 'value moved in previous iteration of loop' message
 
 struct NonCopy;
+//~^ NOTE if `NonCopy` implemented `Clone`
+//~| NOTE if `NonCopy` implemented `Clone`
+//~| NOTE if `NonCopy` implemented `Clone`
+//~| NOTE if `NonCopy` implemented `Clone`
 
 fn good() {
     loop {
diff --git a/tests/ui/moves/issue-72649-uninit-in-loop.stderr b/tests/ui/moves/issue-72649-uninit-in-loop.stderr
diff --git a/tests/ui/moves/move-fn-self-receiver.stderr b/tests/ui/moves/move-fn-self-receiver.stderr
diff --git a/tests/ui/moves/move-out-of-array-1.stderr b/tests/ui/moves/move-out-of-array-1.stderr
diff --git a/tests/ui/nll/issue-21232-partial-init-and-use.stderr b/tests/ui/nll/issue-21232-partial-init-and-use.stderr
diff --git a/tests/ui/nll/move-errors.stderr b/tests/ui/nll/move-errors.stderr
diff --git a/tests/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.stderr b/tests/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.stderr
diff --git a/tests/ui/union/union-borrow-move-parent-sibling.stderr b/tests/ui/union/union-borrow-move-parent-sibling.stderr
diff --git a/tests/ui/union/union-move.stderr b/tests/ui/union/union-move.stderr
diff --git a/tests/ui/variance/variance-issue-20533.stderr b/tests/ui/variance/variance-issue-20533.stderr

Original file line number	Diff line number	Diff line change
`@@ -52,6 +52,11 @@ LL \|`
`52`	`52`	`LL \| println!("{b:?}");`
`53`	`53`	`\| ----- borrow later used here`
`54`	`54`	`\|`
	`55`	+note: if `A` implemented `Clone`, you could clone the value
	`56`	`+ --> $DIR/clone-on-ref.rs:19:1`
	`57`	`+ \|`
	`58`	`+LL \| struct A;`
	`59`	`+ \| ^^^^^^^^`
`55`	`60`	help: consider annotating `A` with `#[derive(Clone)]`
`56`	`61`	`\|`
`57`	`62`	`LL + #[derive(Clone)]`
Original file line number	Diff line number	Diff line change
@@ -4,6 +4,11 @@ error[E0507]: cannot move out of static item `FOO`
`4`	`4`	`LL \| let _a = FOO;`
`5`	`5`	\| ^^^ move occurs because `FOO` has type `Foo`, which does not implement the `Copy` trait
`6`	`6`	`\|`
	`7`	+note: if `Foo` implemented `Clone`, you could clone the value
	`8`	`+ --> $DIR/issue-17718-static-move.rs:1:1`
	`9`	`+ \|`
	`10`	`+LL \| struct Foo;`
	`11`	`+ \| ^^^^^^^^^^`
`7`	`12`	`help: consider borrowing here`
`8`	`13`	`\|`
`9`	`14`	`LL \| let _a = &FOO;`