Rollup merge of rust-lang#57294 - estebank:point-copy-less, r=nikomat…

…sakis When using value after move, point at span of local When trying to use a value after move, instead of using a note, point at the local declaration that has a type that doesn't implement `Copy` trait. ``` error[E0382]: use of moved value: `x` --> $DIR/issue-34721.rs:27:9 | LL | pub fn baz<T: Foo>(x: T) -> T { | - - move occurs because `x` has type `T`, which does not implement the `Copy` trait | | | consider adding a `Copy` constraint to this type argument LL | if 0 == 1 { LL | bar::bar(x.zero()) | - value moved here LL | } else { LL | x.zero() | - value moved here LL | }; LL | x.zero() | ^ value used here after move ``` Fix rust-lang#34721.
Centril · Jan 21, 2019 · 68ea7e4 · 68ea7e4
2 parents 7164a9f + 09006d8
commit 68ea7e4
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diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs
@@ -198,19 +198,38 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 let place = &self.move_data.move_paths[mpi].place;
 
                 let ty = place.ty(self.mir, self.infcx.tcx).to_ty(self.infcx.tcx);
-                let note_msg = match self.describe_place_with_options(
-                    place,
-                    IncludingDowncast(true),
-                ) {
-                    Some(name) => format!("`{}`", name),
+                let opt_name = self.describe_place_with_options(place, IncludingDowncast(true));
+                let note_msg = match opt_name {
+                    Some(ref name) => format!("`{}`", name),
                     None => "value".to_owned(),
                 };
-
-                err.note(&format!(
-                    "move occurs because {} has type `{}`, \
-                     which does not implement the `Copy` trait",
-                    note_msg, ty
-                ));
+                if let ty::TyKind::Param(param_ty) = ty.sty {
+                    let tcx = self.infcx.tcx;
+                    let generics = tcx.generics_of(self.mir_def_id);
+                    let def_id = generics.type_param(&param_ty, tcx).def_id;
+                    if let Some(sp) = tcx.hir().span_if_local(def_id) {
+                        err.span_label(
+                            sp,
+                            "consider adding a `Copy` constraint to this type argument",
+                        );
+                    }
+                }
+                if let Place::Local(local) = place {
+                    let decl = &self.mir.local_decls[*local];
+                    err.span_label(
+                        decl.source_info.span,
+                        format!(
+                            "move occurs because {} has type `{}`, \
+                                which does not implement the `Copy` trait",
+                            note_msg, ty,
+                    ));
+                } else {
+                    err.note(&format!(
+                        "move occurs because {} has type `{}`, \
+                         which does not implement the `Copy` trait",
+                        note_msg, ty
+                    ));
+                }
             }
 
             if let Some((_, mut old_err)) = self.move_error_reported

diff --git a/src/test/ui/borrowck/borrowck-asm.mir.stderr b/src/test/ui/borrowck/borrowck-asm.mir.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-asm.rs:27:17
    |
+LL |         let x = &mut 0isize;
+   |             - move occurs because `x` has type `&mut isize`, which does not implement the `Copy` trait
+LL |         unsafe {
 LL |             asm!("nop" : : "r"(x));
    |                                - value moved here
 LL |         }
 LL |         let z = x;  //[ast]~ ERROR use of moved value: `x`
    |                 ^ value used here after move
-   |
-   = note: move occurs because `x` has type `&mut isize`, which does not implement the `Copy` trait
 
 error[E0503]: cannot use `x` because it was mutably borrowed
   --> $DIR/borrowck-asm.rs:35:32
@@ -66,12 +67,13 @@ LL |         let z = y;
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-asm.rs:86:40
    |
+LL |         let x = &mut 2;
+   |             - move occurs because `x` has type `&mut i32`, which does not implement the `Copy` trait
+LL |         unsafe {
 LL |             asm!("nop" : : "r"(x), "r"(x) );    //[ast]~ ERROR use of moved value
    |                                -       ^ value used here after move
    |                                |
    |                                value moved here
-   |
-   = note: move occurs because `x` has type `&mut i32`, which does not implement the `Copy` trait
 
 error: aborting due to 7 previous errors
 

diff --git a/src/test/ui/borrowck/borrowck-drop-from-guard.stderr b/src/test/ui/borrowck/borrowck-drop-from-guard.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `my_str`
   --> $DIR/borrowck-drop-from-guard.rs:11:23
    |
+LL |     let my_str = "hello".to_owned();
+   |         ------ move occurs because `my_str` has type `std::string::String`, which does not implement the `Copy` trait
+LL |     match Some(42) {
 LL |         Some(_) if { drop(my_str); false } => {}
    |                           ------ value moved here
 LL |         Some(_) => {}
 LL |         None => { foo(my_str); } //~ ERROR [E0382]
    |                       ^^^^^^ value used here after move
-   |
-   = note: move occurs because `my_str` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/borrowck/borrowck-issue-48962.stderr b/src/test/ui/borrowck/borrowck-issue-48962.stderr
@@ -1,22 +1,22 @@
 error[E0382]: use of moved value: `src`
   --> $DIR/borrowck-issue-48962.rs:16:5
    |
+LL |     let mut src = &mut node;
+   |         ------- move occurs because `src` has type `&mut Node`, which does not implement the `Copy` trait
 LL |     {src};
    |      --- value moved here
 LL |     src.next = None; //~ ERROR use of moved value: `src` [E0382]
    |     ^^^^^^^^ value used here after move
-   |
-   = note: move occurs because `src` has type `&mut Node`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `src`
   --> $DIR/borrowck-issue-48962.rs:22:5
    |
+LL |     let mut src = &mut (22, 44);
+   |         ------- move occurs because `src` has type `&mut (i32, i32)`, which does not implement the `Copy` trait
 LL |     {src};
    |      --- value moved here
 LL |     src.0 = 66; //~ ERROR use of moved value: `src` [E0382]
    |     ^^^^^^^^^^ value used here after move
-   |
-   = note: move occurs because `src` has type `&mut (i32, i32)`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 

diff --git a/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.mir.stderr b/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.mir.stderr
@@ -1,6 +1,9 @@
 error[E0382]: use of moved value: `t`
   --> $DIR/borrowck-move-moved-value-into-closure.rs:14:12
    |
+LL |     let t: Box<_> = box 3;
+   |         - move occurs because `t` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
+LL | 
 LL |     call_f(move|| { *t + 1 });
    |            ------    - variable moved due to use in closure
    |            |
@@ -9,8 +12,6 @@ LL |     call_f(move|| { *t + 1 }); //[ast]~ ERROR capture of moved value
    |            ^^^^^^    - use occurs due to use in closure
    |            |
    |            value used here after move
-   |
-   = note: move occurs because `t` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/borrowck/borrowck-reinit.stderr b/src/test/ui/borrowck/borrowck-reinit.stderr
@@ -11,12 +11,13 @@ LL |     let _ = (1,x); //~ ERROR use of moved value: `x` (Ast)
 error[E0382]: use of moved value: `x` (Mir)
   --> $DIR/borrowck-reinit.rs:8:16
    |
+LL |     let mut x = Box::new(0);
+   |         ----- move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
+...
 LL |     drop(x);
    |          - value moved here
 LL |     let _ = (1,x); //~ ERROR use of moved value: `x` (Ast)
    |                ^ value used here after move
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 

diff --git a/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out-with-mut.nll.stderr b/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out-with-mut.nll.stderr
@@ -1,32 +1,32 @@
 error[E0382]: assign to part of moved value: `t`
   --> $DIR/issue-54499-field-mutation-of-moved-out-with-mut.rs:23:9
    |
+LL |         let mut t: Tuple = (S(0), 0);
+   |             ----- move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 LL |         drop(t);
    |              - value moved here
 LL |         t.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `u`
   --> $DIR/issue-54499-field-mutation-of-moved-out-with-mut.rs:34:9
    |
+LL |         let mut u: Tpair = Tpair(S(0), 0);
+   |             ----- move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 LL |         drop(u);
    |              - value moved here
 LL |         u.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `v`
   --> $DIR/issue-54499-field-mutation-of-moved-out-with-mut.rs:45:9
    |
+LL |         let mut v: Spair = Spair { x: S(0), y: 0 };
+   |             ----- move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 LL |         drop(v);
    |              - value moved here
 LL |         v.x = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 
 error: aborting due to 3 previous errors
 

diff --git a/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out.nll.stderr b/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out.nll.stderr
@@ -10,12 +10,12 @@ LL |         t.0 = S(1);
 error[E0382]: assign to part of moved value: `t`
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:23:9
    |
+LL |         let t: Tuple = (S(0), 0);
+   |             - move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 LL |         drop(t);
    |              - value moved here
 LL |         t.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 
 error[E0594]: cannot assign to `t.1`, as `t` is not declared as mutable
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:27:9
@@ -38,12 +38,12 @@ LL |         u.0 = S(1);
 error[E0382]: assign to part of moved value: `u`
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:38:9
    |
+LL |         let u: Tpair = Tpair(S(0), 0);
+   |             - move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 LL |         drop(u);
    |              - value moved here
 LL |         u.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 
 error[E0594]: cannot assign to `u.1`, as `u` is not declared as mutable
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:42:9
@@ -66,12 +66,12 @@ LL |         v.x = S(1);
 error[E0382]: assign to part of moved value: `v`
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:53:9
    |
+LL |         let v: Spair = Spair { x: S(0), y: 0 };
+   |             - move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 LL |         drop(v);
    |              - value moved here
 LL |         v.x = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 
 error[E0594]: cannot assign to `v.y`, as `v` is not declared as mutable
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:57:9

diff --git a/src/test/ui/borrowck/two-phase-nonrecv-autoref.nll.stderr b/src/test/ui/borrowck/two-phase-nonrecv-autoref.nll.stderr
@@ -10,6 +10,8 @@ LL |         f(f(10));
 error[E0382]: use of moved value: `*f`
   --> $DIR/two-phase-nonrecv-autoref.rs:69:11
    |
+LL |     fn twice_ten_so<F: FnOnce(i32) -> i32>(f: Box<F>) {
+   |                     - consider adding a `Copy` constraint to this type argument
 LL |         f(f(10));
    |         - ^ value used here after move
    |         |

diff --git a/src/test/ui/issues/issue-27282-move-match-input-into-guard.stderr b/src/test/ui/issues/issue-27282-move-match-input-into-guard.stderr
@@ -1,15 +1,16 @@
 error[E0382]: use of moved value: `b`
   --> $DIR/issue-27282-move-match-input-into-guard.rs:18:14
    |
+LL |     let b = &mut true;
+   |         - move occurs because `b` has type `&mut bool`, which does not implement the `Copy` trait
+...
 LL |         _ if { (|| { let bar = b; *bar = false; })();
    |                 --             - variable moved due to use in closure
    |                 |
    |                 value moved into closure here
 LL |                      false } => { },
 LL |         &mut true => { println!("You might think we should get here"); },
    |              ^^^^ value used here after move
-   |
-   = note: move occurs because `b` has type `&mut bool`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/issues/issue-29723.stderr b/src/test/ui/issues/issue-29723.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `s`
   --> $DIR/issue-29723.rs:12:13
    |
+LL |     let s = String::new();
+   |         - move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
+LL |     let _s = match 0 {
 LL |         0 if { drop(s); false } => String::from("oops"),
    |                     - value moved here
 ...
 LL |             s
    |             ^ value used here after move
-   |
-   = note: move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/issues/issue-34721.rs b/src/test/ui/issues/issue-34721.rs
@@ -0,0 +1,34 @@
+#![feature(nll)]
+
+pub trait Foo {
+    fn zero(self) -> Self;
+}
+
+impl Foo for u32 {
+    fn zero(self) -> u32 { 0u32 }
+}
+
+pub mod bar {
+    pub use Foo;
+    pub fn bar<T: Foo>(x: T) -> T {
+      x.zero()
+    }
+}
+
+mod baz {
+    use bar;
+    use Foo;
+    pub fn baz<T: Foo>(x: T) -> T {
+        if 0 == 1 {
+            bar::bar(x.zero())
+        } else {
+            x.zero()
+        };
+        x.zero()
+        //~^ ERROR use of moved value
+    }
+}
+
+fn main() {
+    let _ = baz::baz(0u32);
+}
diff --git a/src/test/ui/issues/issue-34721.stderr b/src/test/ui/issues/issue-34721.stderr
@@ -0,0 +1,20 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/issue-34721.rs:27:9
+   |
+LL |     pub fn baz<T: Foo>(x: T) -> T {
+   |                -       - move occurs because `x` has type `T`, which does not implement the `Copy` trait
+   |                |
+   |                consider adding a `Copy` constraint to this type argument
+LL |         if 0 == 1 {
+LL |             bar::bar(x.zero())
+   |                      - value moved here
+LL |         } else {
+LL |             x.zero()
+   |             - value moved here
+LL |         };
+LL |         x.zero()
+   |         ^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/moves/moves-based-on-type-tuple.stderr b/src/test/ui/moves/moves-based-on-type-tuple.stderr
@@ -11,12 +11,12 @@ LL |     box (x, x)
 error[E0382]: use of moved value: `x` (Mir)
   --> $DIR/moves-based-on-type-tuple.rs:6:13
    |
+LL | fn dup(x: Box<isize>) -> Box<(Box<isize>,Box<isize>)> {
+   |        - move occurs because `x` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 LL |     box (x, x)
    |          -  ^ value used here after move
    |          |
    |          value moved here
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors