More move error suggestions to clone

estebank · estebank · commit 91bbbf12e01f · 2024-03-16T18:19:41.000Z
```
error[E0507]: cannot move out of `val`, a captured variable in an `FnMut` closure
  --&gt; $DIR/issue-87456-point-to-closure.rs:10:28
   |
LL |     let val = String::new();
   |         --- captured outer variable
LL |
LL |     take_mut(|| {
   |              -- captured by this `FnMut` closure
LL |
LL |         let _foo: String = val;
   |                            ^^^ move occurs because `val` has type `String`, which does not implement the `Copy` trait
   |
help: consider borrowing here
   |
LL |         let _foo: String = &amp;val;
   |                            +
help: consider cloning the value if the performance cost is acceptable
   |
LL |         let _foo: String = val.clone();
   |                               ++++++++
```
diff --git a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
@@ -444,6 +444,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         None => "value".to_string(),
                     };
 
+                    if let Some(expr) = self.find_expr(span) {
+                        self.suggest_cloning(err, place_ty, expr, span);
+                    }
+
                     err.subdiagnostic(
                         self.dcx(),
                         crate::session_diagnostics::TypeNoCopy::Label {
diff --git a/tests/ui/borrowck/borrowck-issue-2657-2.fixed b/tests/ui/borrowck/borrowck-issue-2657-2.fixed
@@ -5,7 +5,7 @@ fn main() {
 
     match x {
       Some(ref y) => {
-        let _b = y; //~ ERROR cannot move out
+        let _b = y.clone(); //~ ERROR cannot move out
       }
       _ => {}
     }
diff --git a/tests/ui/borrowck/borrowck-issue-2657-2.stderr b/tests/ui/borrowck/borrowck-issue-2657-2.stderr
@@ -9,6 +9,11 @@ help: consider removing the dereference here
 LL -         let _b = *y;
 LL +         let _b = y;
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -         let _b = *y;
+LL +         let _b = y.clone();
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-move-from-unsafe-ptr.stderr b/tests/ui/borrowck/borrowck-move-from-unsafe-ptr.stderr
@@ -9,6 +9,11 @@ help: consider removing the dereference here
 LL -     let y = *x;
 LL +     let y = x;
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let y = *x;
+LL +     let y = x.clone();
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-move-out-of-overloaded-deref.stderr b/tests/ui/borrowck/borrowck-move-out-of-overloaded-deref.stderr
@@ -9,6 +9,11 @@ help: consider removing the dereference here
 LL -     let _x = *Rc::new("hi".to_string());
 LL +     let _x = Rc::new("hi".to_string());
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let _x = *Rc::new("hi".to_string());
+LL +     let _x = Rc::new("hi".to_string()).clone();
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-overloaded-index-move-from-vec.stderr b/tests/ui/borrowck/borrowck-overloaded-index-move-from-vec.stderr
@@ -8,6 +8,10 @@ help: consider borrowing here
    |
 LL |     let bad = &v[0];
    |               +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let bad = v[0].clone();
+   |                   ++++++++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/borrowck/borrowck-vec-pattern-nesting.rs b/tests/ui/borrowck/borrowck-vec-pattern-nesting.rs
@@ -47,6 +47,7 @@ fn c() {
     //~| NOTE cannot move out of here
     //~| NOTE move occurs because
     //~| HELP consider borrowing here
+    //~| HELP consider cloning
 }
 
 fn d() {
@@ -66,6 +67,7 @@ fn d() {
     //~| NOTE cannot move out of here
     //~| NOTE move occurs because
     //~| HELP consider borrowing here
+    //~| HELP consider cloning
 }
 
 fn e() {
@@ -86,6 +88,7 @@ fn e() {
     //~| NOTE cannot move out of here
     //~| NOTE move occurs because
     //~| HELP consider borrowing here
+    //~| HELP consider cloning
 }
 
 fn main() {}
diff --git a/tests/ui/borrowck/borrowck-vec-pattern-nesting.stderr b/tests/ui/borrowck/borrowck-vec-pattern-nesting.stderr
@@ -53,9 +53,13 @@ help: consider borrowing here
    |
 LL |     let a = &vec[0];
    |             +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let a = vec[0].clone();
+   |                   ++++++++
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:55:11
+  --> $DIR/borrowck-vec-pattern-nesting.rs:56:11
    |
 LL |     match vec {
    |           ^^^ cannot move out of here
@@ -73,7 +77,7 @@ LL +         [
    |
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:65:13
+  --> $DIR/borrowck-vec-pattern-nesting.rs:66:13
    |
 LL |     let a = vec[0];
    |             ^^^^^^
@@ -85,9 +89,13 @@ help: consider borrowing here
    |
 LL |     let a = &vec[0];
    |             +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let a = vec[0].clone();
+   |                   ++++++++
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:74:11
+  --> $DIR/borrowck-vec-pattern-nesting.rs:76:11
    |
 LL |     match vec {
    |           ^^^ cannot move out of here
@@ -106,7 +114,7 @@ LL +         [_a, _b, _c] => {}
    |
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:85:13
+  --> $DIR/borrowck-vec-pattern-nesting.rs:87:13
    |
 LL |     let a = vec[0];
    |             ^^^^^^
@@ -118,6 +126,10 @@ help: consider borrowing here
    |
 LL |     let a = &vec[0];
    |             +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let a = vec[0].clone();
+   |                   ++++++++
 
 error: aborting due to 8 previous errors
 
diff --git a/tests/ui/borrowck/issue-87456-point-to-closure.stderr b/tests/ui/borrowck/issue-87456-point-to-closure.stderr
@@ -14,6 +14,10 @@ help: consider borrowing here
    |
 LL |         let _foo: String = &val;
    |                            +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |         let _foo: String = val.clone();
+   |                               ++++++++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/check-static-values-constraints.stderr b/tests/ui/check-static-values-constraints.stderr
@@ -157,6 +157,10 @@ help: consider borrowing here
    |
 LL |         &x
    |         +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |         x.clone()
+   |          ++++++++
 
 error: aborting due to 17 previous errors
 
diff --git a/tests/ui/issues/issue-40402-ref-hints/issue-40402-1.stderr b/tests/ui/issues/issue-40402-ref-hints/issue-40402-1.stderr
@@ -8,6 +8,10 @@ help: consider borrowing here
    |
 LL |     let e = &f.v[0];
    |             +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let e = f.v[0].clone();
+   |                   ++++++++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/nll/cannot-move-block-spans.stderr b/tests/ui/nll/cannot-move-block-spans.stderr
@@ -9,6 +9,11 @@ help: consider removing the dereference here
 LL -     let x = { *r };
 LL +     let x = { r };
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let x = { *r };
+LL +     let x = { r.clone() };
+   |
 
 error[E0507]: cannot move out of `*r` which is behind a shared reference
   --> $DIR/cannot-move-block-spans.rs:6:22
@@ -21,6 +26,11 @@ help: consider removing the dereference here
 LL -     let y = unsafe { *r };
 LL +     let y = unsafe { r };
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let y = unsafe { *r };
+LL +     let y = unsafe { r.clone() };
+   |
 
 error[E0507]: cannot move out of `*r` which is behind a shared reference
   --> $DIR/cannot-move-block-spans.rs:7:26
@@ -33,6 +43,11 @@ help: consider removing the dereference here
 LL -     let z = loop { break *r; };
 LL +     let z = loop { break r; };
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let z = loop { break *r; };
+LL +     let z = loop { break r.clone(); };
+   |
 
 error[E0508]: cannot move out of type `[String; 2]`, a non-copy array
   --> $DIR/cannot-move-block-spans.rs:11:15
@@ -47,6 +62,10 @@ help: consider borrowing here
    |
 LL |     let x = { &arr[0] };
    |               +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let x = { arr[0].clone() };
+   |                     ++++++++
 
 error[E0508]: cannot move out of type `[String; 2]`, a non-copy array
   --> $DIR/cannot-move-block-spans.rs:12:22
@@ -61,6 +80,10 @@ help: consider borrowing here
    |
 LL |     let y = unsafe { &arr[0] };
    |                      +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let y = unsafe { arr[0].clone() };
+   |                            ++++++++
 
 error[E0508]: cannot move out of type `[String; 2]`, a non-copy array
   --> $DIR/cannot-move-block-spans.rs:13:26
@@ -75,6 +98,10 @@ help: consider borrowing here
    |
 LL |     let z = loop { break &arr[0]; };
    |                          +
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     let z = loop { break arr[0].clone(); };
+   |                                ++++++++
 
 error[E0507]: cannot move out of `*r` which is behind a shared reference
   --> $DIR/cannot-move-block-spans.rs:17:38
@@ -87,6 +114,11 @@ help: consider removing the dereference here
 LL -     let x = { let mut u = 0; u += 1; *r };
 LL +     let x = { let mut u = 0; u += 1; r };
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let x = { let mut u = 0; u += 1; *r };
+LL +     let x = { let mut u = 0; u += 1; r.clone() };
+   |
 
 error[E0507]: cannot move out of `*r` which is behind a shared reference
   --> $DIR/cannot-move-block-spans.rs:18:45
@@ -99,6 +131,11 @@ help: consider removing the dereference here
 LL -     let y = unsafe { let mut u = 0; u += 1; *r };
 LL +     let y = unsafe { let mut u = 0; u += 1; r };
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let y = unsafe { let mut u = 0; u += 1; *r };
+LL +     let y = unsafe { let mut u = 0; u += 1; r.clone() };
+   |
 
 error[E0507]: cannot move out of `*r` which is behind a shared reference
   --> $DIR/cannot-move-block-spans.rs:19:49
@@ -111,6 +148,11 @@ help: consider removing the dereference here
 LL -     let z = loop { let mut u = 0; u += 1; break *r; u += 2; };
 LL +     let z = loop { let mut u = 0; u += 1; break r; u += 2; };
    |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL -     let z = loop { let mut u = 0; u += 1; break *r; u += 2; };
+LL +     let z = loop { let mut u = 0; u += 1; break r.clone(); u += 2; };
+   |
 
 error: aborting due to 9 previous errors
 

Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ fn main() {`
`5`	`5`
`6`	`6`	`match x {`
`7`	`7`	`Some(ref y) => {`
`8`		`- let _b = y; //~ ERROR cannot move out`
	`8`	`+ let _b = y.clone(); //~ ERROR cannot move out`
`9`	`9`	`}`
`10`	`10`	`_ => {}`
`11`	`11`	`}`
Original file line number	Diff line number	Diff line change
`@@ -8,6 +8,10 @@ help: consider borrowing here`
`8`	`8`	`\|`
`9`	`9`	`LL \| let bad = &v[0];`
`10`	`10`	`\| +`
	`11`	`+help: consider cloning the value if the performance cost is acceptable`
	`12`	`+ \|`
	`13`	`+LL \| let bad = v[0].clone();`
	`14`	`+ \| ++++++++`
`11`	`15`
`12`	`16`	`error: aborting due to 1 previous error`
`13`	`17`
Original file line number	Diff line number	Diff line change
`@@ -47,6 +47,7 @@ fn c() {`
`47`	`47`	`//~\| NOTE cannot move out of here`
`48`	`48`	`//~\| NOTE move occurs because`
`49`	`49`	`//~\| HELP consider borrowing here`
	`50`	`+ //~\| HELP consider cloning`
`50`	`51`	`}`
`51`	`52`
`52`	`53`	`fn d() {`
`@@ -66,6 +67,7 @@ fn d() {`
`66`	`67`	`//~\| NOTE cannot move out of here`
`67`	`68`	`//~\| NOTE move occurs because`
`68`	`69`	`//~\| HELP consider borrowing here`
	`70`	`+ //~\| HELP consider cloning`
`69`	`71`	`}`
`70`	`72`
`71`	`73`	`fn e() {`
`@@ -86,6 +88,7 @@ fn e() {`
`86`	`88`	`//~\| NOTE cannot move out of here`
`87`	`89`	`//~\| NOTE move occurs because`
`88`	`90`	`//~\| HELP consider borrowing here`
	`91`	`+ //~\| HELP consider cloning`
`89`	`92`	`}`
`90`	`93`
`91`	`94`	`fn main() {}`
Original file line number	Diff line number	Diff line change
`@@ -53,9 +53,13 @@ help: consider borrowing here`
`53`	`53`	`\|`
`54`	`54`	`LL \| let a = &vec[0];`
`55`	`55`	`\| +`
	`56`	`+help: consider cloning the value if the performance cost is acceptable`
	`57`	`+ \|`
	`58`	`+LL \| let a = vec[0].clone();`
	`59`	`+ \| ++++++++`
`56`	`60`
`57`	`61`	error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
`58`		`- --> $DIR/borrowck-vec-pattern-nesting.rs:55:11`
	`62`	`+ --> $DIR/borrowck-vec-pattern-nesting.rs:56:11`
`59`	`63`	`\|`
`60`	`64`	`LL \| match vec {`
`61`	`65`	`\| ^^^ cannot move out of here`
`@@ -73,7 +77,7 @@ LL + [`
`73`	`77`	`\|`
`74`	`78`
`75`	`79`	error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
`76`		`- --> $DIR/borrowck-vec-pattern-nesting.rs:65:13`
	`80`	`+ --> $DIR/borrowck-vec-pattern-nesting.rs:66:13`
`77`	`81`	`\|`
`78`	`82`	`LL \| let a = vec[0];`
`79`	`83`	`\| ^^^^^^`
`@@ -85,9 +89,13 @@ help: consider borrowing here`
`85`	`89`	`\|`
`86`	`90`	`LL \| let a = &vec[0];`
`87`	`91`	`\| +`
	`92`	`+help: consider cloning the value if the performance cost is acceptable`
	`93`	`+ \|`
	`94`	`+LL \| let a = vec[0].clone();`
	`95`	`+ \| ++++++++`
`88`	`96`
`89`	`97`	error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
`90`		`- --> $DIR/borrowck-vec-pattern-nesting.rs:74:11`
	`98`	`+ --> $DIR/borrowck-vec-pattern-nesting.rs:76:11`
`91`	`99`	`\|`
`92`	`100`	`LL \| match vec {`
`93`	`101`	`\| ^^^ cannot move out of here`
`@@ -106,7 +114,7 @@ LL + [_a, _b, _c] => {}`
`106`	`114`	`\|`
`107`	`115`
`108`	`116`	error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
`109`		`- --> $DIR/borrowck-vec-pattern-nesting.rs:85:13`
	`117`	`+ --> $DIR/borrowck-vec-pattern-nesting.rs:87:13`
`110`	`118`	`\|`
`111`	`119`	`LL \| let a = vec[0];`
`112`	`120`	`\| ^^^^^^`
`@@ -118,6 +126,10 @@ help: consider borrowing here`
`118`	`126`	`\|`
`119`	`127`	`LL \| let a = &vec[0];`
`120`	`128`	`\| +`
	`129`	`+help: consider cloning the value if the performance cost is acceptable`
	`130`	`+ \|`
	`131`	`+LL \| let a = vec[0].clone();`
	`132`	`+ \| ++++++++`
`121`	`133`
`122`	`134`	`error: aborting due to 8 previous errors`
`123`	`135`
Original file line number	Diff line number	Diff line change
`@@ -14,6 +14,10 @@ help: consider borrowing here`
`14`	`14`	`\|`
`15`	`15`	`LL \| let _foo: String = &val;`
`16`	`16`	`\| +`
	`17`	`+help: consider cloning the value if the performance cost is acceptable`
	`18`	`+ \|`
	`19`	`+LL \| let _foo: String = val.clone();`
	`20`	`+ \| ++++++++`
`17`	`21`
`18`	`22`	`error: aborting due to 1 previous error`
`19`	`23`
Original file line number	Diff line number	Diff line change
`@@ -157,6 +157,10 @@ help: consider borrowing here`
`157`	`157`	`\|`
`158`	`158`	`LL \| &x`
`159`	`159`	`\| +`
	`160`	`+help: consider cloning the value if the performance cost is acceptable`
	`161`	`+ \|`
	`162`	`+LL \| x.clone()`
	`163`	`+ \| ++++++++`
`160`	`164`
`161`	`165`	`error: aborting due to 17 previous errors`
`162`	`166`