Rollup merge of #86673 - m-ou-se:disjoint-capture-edition-lint, r=nikomatsakis

Make disjoint_capture_migration an edition lint.

This turns the disjoint capture lint into an edition lint, and changes all the wording to refer to the edition.

This includes the same first commit as https://github.com/rust-lang/rust/pull/86671. See https://github.com/rust-lang/rust/pull/86671.

Fixes most of https://github.com/rust-lang/project-rfc-2229/issues/43#issuecomment-869188197

compiler/rustc_lint_defs/src/builtin.rs

@@ -3002,8 +3002,7 @@ declare_lint! {
 
 declare_lint! {
     /// The `disjoint_capture_migration` lint detects variables that aren't completely
-    /// captured when the feature `capture_disjoint_fields` is enabled and it affects the Drop
-    /// order of at least one path starting at this variable.
+    /// captured in Rust 2021 and affect the Drop order of at least one path starting at this variable.
     /// It can also detect when a variable implements a trait, but one of its field does not and
     /// the field is captured by a closure and used with the assumption that said field implements
     /// the same trait as the root variable.
@@ -3040,8 +3039,8 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// In the above example `p.y` will be dropped at the end of `f` instead of with `c` if
-    /// the feature `capture_disjoint_fields` is enabled.
+    /// In the above example, `p.y` will be dropped at the end of `f` instead of
+    /// with `c` in Rust 2021.
     ///
     /// ### Example of auto-trait
     ///
@@ -3049,7 +3048,7 @@ declare_lint! {
     /// #![deny(disjoint_capture_migration)]
     /// use std::thread;
     ///
-    /// struct Pointer (*mut i32);
+    /// struct Pointer(*mut i32);
     /// unsafe impl Send for Pointer {}
     ///
     /// fn main() {
@@ -3065,12 +3064,16 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// In the above example `fptr.0` is captured when feature `capture_disjoint_fields` is enabled.
+    /// In the above example, only `fptr.0` is captured in Rust 2021.
     /// The field is of type *mut i32 which doesn't implement Send, making the code invalid as the
     /// field cannot be sent between thread safely.
     pub DISJOINT_CAPTURE_MIGRATION,
     Allow,
-    "Drop reorder and auto traits error because of `capture_disjoint_fields`"
+    "detects closures affected by Rust 2021 changes",
+    @future_incompatible = FutureIncompatibleInfo {
+        reason: FutureIncompatibilityReason::EditionSemanticsChange(Edition::Edition2021),
+        explain_reason: false,
+    };
 }
 
 declare_lint_pass!(UnusedDocComment => [UNUSED_DOC_COMMENTS]);

compiler/rustc_typeck/src/check/upvar.rs

@@ -495,11 +495,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 |lint| {
                     let mut diagnostics_builder = lint.build(
                         format!(
-                            "{} affected for closure because of `capture_disjoint_fields`",
+                            "{} will change in Rust 2021",
                             reasons
                         )
                         .as_str(),
                     );
+                    diagnostics_builder.note("for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>");
                     let closure_body_span = self.tcx.hir().span(body_id.hir_id);
                     let (sugg, app) =
                         match self.tcx.sess.source_map().span_to_snippet(closure_body_span) {

src/test/ui/closures/2229_closure_analysis/migrations/auto_traits.fixed

@@ -11,7 +11,7 @@ fn test_send_trait() {
     let mut f = 10;
     let fptr = SendPointer(&mut f as *mut i32);
     thread::spawn(move || { let _ = &fptr; unsafe {
-        //~^ ERROR: `Send` trait implementation affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `Send` trait implementation
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0 = 20;
     } });
@@ -28,7 +28,7 @@ fn test_sync_trait() {
     let f = CustomInt(&mut f as *mut i32);
     let fptr = SyncPointer(f);
     thread::spawn(move || { let _ = &fptr; unsafe {
-        //~^ ERROR: `Sync`, `Send` trait implementation affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `Sync`, `Send` trait implementation
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0.0 = 20;
     } });
@@ -49,7 +49,7 @@ impl Clone for U {
 fn test_clone_trait() {
     let f = U(S(String::from("Hello World")), T(0));
     let c = || { let _ = &f; 
-        //~^ ERROR: `Clone` trait implementation, and drop order affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `Clone` trait implementation, and drop order
         //~| HELP: add a dummy let to cause `f` to be fully captured
         let f_1 = f.1;
         println!("{:?}", f_1.0);

src/test/ui/closures/2229_closure_analysis/migrations/auto_traits.rs

@@ -11,7 +11,7 @@ fn test_send_trait() {
     let mut f = 10;
     let fptr = SendPointer(&mut f as *mut i32);
     thread::spawn(move || unsafe {
-        //~^ ERROR: `Send` trait implementation affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `Send` trait implementation
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0 = 20;
     });
@@ -28,7 +28,7 @@ fn test_sync_trait() {
     let f = CustomInt(&mut f as *mut i32);
     let fptr = SyncPointer(f);
     thread::spawn(move || unsafe {
-        //~^ ERROR: `Sync`, `Send` trait implementation affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `Sync`, `Send` trait implementation
         //~| HELP: add a dummy let to cause `fptr` to be fully captured
         *fptr.0.0 = 20;
     });
@@ -49,7 +49,7 @@ impl Clone for U {
 fn test_clone_trait() {
     let f = U(S(String::from("Hello World")), T(0));
     let c = || {
-        //~^ ERROR: `Clone` trait implementation, and drop order affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `Clone` trait implementation, and drop order
         //~| HELP: add a dummy let to cause `f` to be fully captured
         let f_1 = f.1;
         println!("{:?}", f_1.0);

src/test/ui/closures/2229_closure_analysis/migrations/auto_traits.stderr

@@ -1,4 +1,4 @@
-error: `Send` trait implementation affected for closure because of `capture_disjoint_fields`
+error: `Send` trait implementation will change in Rust 2021
   --> $DIR/auto_traits.rs:13:19
    |
 LL |       thread::spawn(move || unsafe {
@@ -14,6 +14,7 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `fptr` to be fully captured
    |
 LL |     thread::spawn(move || { let _ = &fptr; unsafe {
@@ -23,7 +24,7 @@ LL |         *fptr.0 = 20;
 LL |     } });
    |
 
-error: `Sync`, `Send` trait implementation affected for closure because of `capture_disjoint_fields`
+error: `Sync`, `Send` trait implementation will change in Rust 2021
   --> $DIR/auto_traits.rs:30:19
    |
 LL |       thread::spawn(move || unsafe {
@@ -34,6 +35,7 @@ LL | |         *fptr.0.0 = 20;
 LL | |     });
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `fptr` to be fully captured
    |
 LL |     thread::spawn(move || { let _ = &fptr; unsafe {
@@ -43,7 +45,7 @@ LL |         *fptr.0.0 = 20;
 LL |     } });
    |
 
-error: `Clone` trait implementation, and drop order affected for closure because of `capture_disjoint_fields`
+error: `Clone` trait implementation, and drop order will change in Rust 2021
   --> $DIR/auto_traits.rs:51:13
    |
 LL |       let c = || {
@@ -55,6 +57,7 @@ LL | |         println!("{:?}", f_1.0);
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `f` to be fully captured
    |
 LL |     let c = || { let _ = &f; 

src/test/ui/closures/2229_closure_analysis/migrations/insignificant_drop.fixed

@@ -13,7 +13,8 @@ fn test1_all_need_migration() {
     let t2 = (String::new(), String::new());
 
     let c = || { let _ = (&t, &t1, &t2); 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1`, `t2` to be fully captured
 
         let _t = t.0;
@@ -32,7 +33,8 @@ fn test2_only_precise_paths_need_migration() {
     let t2 = (String::new(), String::new());
 
     let c = || { let _ = (&t, &t1); 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -48,7 +50,8 @@ fn test3_only_by_value_need_migration() {
     let t = (String::new(), String::new());
     let t1 = (String::new(), String::new());
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         println!("{}", t1.1);
@@ -66,7 +69,8 @@ fn test4_only_non_copy_types_need_migration() {
     let t1 = (0i32, 0i32);
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -84,7 +88,8 @@ fn test5_only_drop_types_need_migration() {
     let s = S(0i32, 0i32);
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         let _s = s.0;
@@ -99,7 +104,8 @@ fn test6_move_closures_non_copy_types_might_need_migration() {
     let t = (String::new(), String::new());
     let t1 = (String::new(), String::new());
     let c = move || { let _ = (&t1, &t); 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t1`, `t` to be fully captured
         println!("{} {}", t1.1, t.1);
     };
@@ -114,7 +120,8 @@ fn test7_drop_non_drop_aggregate_need_migration() {
     let t = (String::new(), String::new(), 0i32);
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };

src/test/ui/closures/2229_closure_analysis/migrations/insignificant_drop.rs

@@ -13,7 +13,8 @@ fn test1_all_need_migration() {
     let t2 = (String::new(), String::new());
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1`, `t2` to be fully captured
 
         let _t = t.0;
@@ -32,7 +33,8 @@ fn test2_only_precise_paths_need_migration() {
     let t2 = (String::new(), String::new());
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -48,7 +50,8 @@ fn test3_only_by_value_need_migration() {
     let t = (String::new(), String::new());
     let t1 = (String::new(), String::new());
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         println!("{}", t1.1);
@@ -66,7 +69,8 @@ fn test4_only_non_copy_types_need_migration() {
     let t1 = (0i32, 0i32);
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -84,7 +88,8 @@ fn test5_only_drop_types_need_migration() {
     let s = S(0i32, 0i32);
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         let _s = s.0;
@@ -99,7 +104,8 @@ fn test6_move_closures_non_copy_types_might_need_migration() {
     let t = (String::new(), String::new());
     let t1 = (String::new(), String::new());
     let c = move || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t1`, `t` to be fully captured
         println!("{} {}", t1.1, t.1);
     };
@@ -114,7 +120,8 @@ fn test7_drop_non_drop_aggregate_need_migration() {
     let t = (String::new(), String::new(), 0i32);
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };

src/test/ui/closures/2229_closure_analysis/migrations/insignificant_drop.stderr

@@ -1,4 +1,4 @@
-error: drop order affected for closure because of `capture_disjoint_fields`
+error: drop order will change in Rust 2021
   --> $DIR/insignificant_drop.rs:15:13
    |
 LL |       let c = || {
@@ -16,141 +16,155 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t`, `t1`, `t2` to be fully captured
    |
 LL |     let c = || { let _ = (&t, &t1, &t2); 
 LL |
 LL |
+LL |
 LL | 
 LL |         let _t = t.0;
-LL |         let _t1 = t1.0;
  ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop.rs:34:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop.rs:35:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
-LL | |         let _t = t.0;
-LL | |         let _t1 = t1.0;
+LL | |
+...  |
 LL | |         let _t2 = t2;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t`, `t1` to be fully captured
    |
 LL |     let c = || { let _ = (&t, &t1); 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         let _t1 = t1.0;
-LL |         let _t2 = t2;
  ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop.rs:50:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop.rs:52:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |         println!("{}", t1.1);
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         println!("{}", t1.1);
-LL |     };
-   |
+ ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop.rs:68:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop.rs:71:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |         let _t1 = t1.0;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         let _t1 = t1.0;
-LL |     };
-   |
+ ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop.rs:86:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop.rs:90:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |         let _s = s.0;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         let _s = s.0;
-LL |     };
-   |
+ ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop.rs:101:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop.rs:106:13
    |
 LL |       let c = move || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         println!("{} {}", t1.1, t.1);
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t1`, `t` to be fully captured
    |
 LL |     let c = move || { let _ = (&t1, &t); 
 LL |
 LL |
+LL |
 LL |         println!("{} {}", t1.1, t.1);
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop.rs:116:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop.rs:122:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |     };
    |

src/test/ui/closures/2229_closure_analysis/migrations/insignificant_drop_attr_migrations.fixed

@@ -36,7 +36,8 @@ fn significant_drop_needs_migration() {
     let t = (SigDrop {}, SigDrop {});
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -53,7 +54,8 @@ fn generic_struct_with_significant_drop_needs_migration() {
 
     // move is used to force i32 to be copied instead of being a ref
     let c = move || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.1;
     };

src/test/ui/closures/2229_closure_analysis/migrations/insignificant_drop_attr_migrations.rs

@@ -36,7 +36,8 @@ fn significant_drop_needs_migration() {
     let t = (SigDrop {}, SigDrop {});
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -53,7 +54,8 @@ fn generic_struct_with_significant_drop_needs_migration() {
 
     // move is used to force i32 to be copied instead of being a ref
     let c = move || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.1;
     };

src/test/ui/closures/2229_closure_analysis/migrations/insignificant_drop_attr_migrations.stderr

@@ -1,10 +1,11 @@
-error: drop order affected for closure because of `capture_disjoint_fields`
+error: drop order will change in Rust 2021
   --> $DIR/insignificant_drop_attr_migrations.rs:38:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |     };
    | |_____^
@@ -14,31 +15,36 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/insignificant_drop_attr_migrations.rs:55:13
+error: drop order will change in Rust 2021
+  --> $DIR/insignificant_drop_attr_migrations.rs:56:13
    |
 LL |       let c = move || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.1;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = move || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.1;
 LL |     };
    |

src/test/ui/closures/2229_closure_analysis/migrations/migrations_rustfix.fixed

@@ -17,7 +17,8 @@ impl Drop for Foo {
 fn closure_contains_block() {
     let t = (Foo(0), Foo(0));
     let c = || { let _ = &t; 
-        //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: drop order
+        //~| NOTE: for more information, see
         //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -28,7 +29,8 @@ fn closure_contains_block() {
 fn closure_doesnt_contain_block() {
     let t = (Foo(0), Foo(0));
     let c = || { let _ = &t; t.0 };
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
 
     c();

src/test/ui/closures/2229_closure_analysis/migrations/migrations_rustfix.rs

@@ -17,7 +17,8 @@ impl Drop for Foo {
 fn closure_contains_block() {
     let t = (Foo(0), Foo(0));
     let c = || {
-        //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: drop order
+        //~| NOTE: for more information, see
         //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -28,7 +29,8 @@ fn closure_contains_block() {
 fn closure_doesnt_contain_block() {
     let t = (Foo(0), Foo(0));
     let c = || t.0;
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
 
     c();

src/test/ui/closures/2229_closure_analysis/migrations/migrations_rustfix.stderr

@@ -1,10 +1,11 @@
-error: drop order affected for closure because of `capture_disjoint_fields`
+error: drop order will change in Rust 2021
   --> $DIR/migrations_rustfix.rs:19:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |     };
    | |_____^
@@ -14,21 +15,24 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/migrations_rustfix.rs:30:13
+error: drop order will change in Rust 2021
+  --> $DIR/migrations_rustfix.rs:31:13
    |
 LL |     let c = || t.0;
    |             ^^^^^^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; t.0 };

src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.fixed

@@ -13,7 +13,7 @@ fn foo_diverges() -> ! { panic!() }
 fn assert_panics<F>(f: F) where F: FnOnce() {
     let f = panic::AssertUnwindSafe(f);
     let result = panic::catch_unwind(move || { let _ = &f; 
-        //~^ ERROR: `UnwindSafe`, `RefUnwindSafe` trait implementation affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `UnwindSafe`, `RefUnwindSafe` trait implementation
         //~| HELP: add a dummy let to cause `f` to be fully captured
         f.0()
     });

src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.rs

@@ -13,7 +13,7 @@ fn foo_diverges() -> ! { panic!() }
 fn assert_panics<F>(f: F) where F: FnOnce() {
     let f = panic::AssertUnwindSafe(f);
     let result = panic::catch_unwind(move || {
-        //~^ ERROR: `UnwindSafe`, `RefUnwindSafe` trait implementation affected for closure because of `capture_disjoint_fields`
+        //~^ ERROR: `UnwindSafe`, `RefUnwindSafe` trait implementation
         //~| HELP: add a dummy let to cause `f` to be fully captured
         f.0()
     });

src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.stderr

@@ -1,4 +1,4 @@
-error: `UnwindSafe`, `RefUnwindSafe` trait implementation affected for closure because of `capture_disjoint_fields`
+error: `UnwindSafe`, `RefUnwindSafe` trait implementation will change in Rust 2021
   --> $DIR/mir_calls_to_shims.rs:15:38
    |
 LL |       let result = panic::catch_unwind(move || {
@@ -14,6 +14,7 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `f` to be fully captured
    |
 LL |     let result = panic::catch_unwind(move || { let _ = &f; 

src/test/ui/closures/2229_closure_analysis/migrations/precise.fixed

@@ -17,7 +17,7 @@ fn test_precise_analysis_drop_paths_not_captured_by_move() {
     let t = ConstainsDropField(Foo(10), Foo(20));
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         let _t = &t.1;
@@ -40,7 +40,7 @@ fn test_precise_analysis_long_path_missing() {
     let u = U(T(S, S), T(S, S));
 
     let c = || { let _ = &u; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
     //~| HELP: add a dummy let to cause `u` to be fully captured
         let _x = u.0.0;
         let _x = u.0.1;

src/test/ui/closures/2229_closure_analysis/migrations/precise.rs

@@ -17,7 +17,7 @@ fn test_precise_analysis_drop_paths_not_captured_by_move() {
     let t = ConstainsDropField(Foo(10), Foo(20));
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         let _t = &t.1;
@@ -40,7 +40,7 @@ fn test_precise_analysis_long_path_missing() {
     let u = U(T(S, S), T(S, S));
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
     //~| HELP: add a dummy let to cause `u` to be fully captured
         let _x = u.0.0;
         let _x = u.0.1;

src/test/ui/closures/2229_closure_analysis/migrations/precise.stderr

@@ -1,4 +1,4 @@
-error: drop order affected for closure because of `capture_disjoint_fields`
+error: drop order will change in Rust 2021
   --> $DIR/precise.rs:19:13
    |
 LL |       let c = || {
@@ -15,6 +15,7 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
@@ -25,7 +26,7 @@ LL |         let _t = &t.1;
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
+error: drop order will change in Rust 2021
   --> $DIR/precise.rs:42:13
    |
 LL |       let c = || {
@@ -38,6 +39,7 @@ LL | |         let _x = u.1.0;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `u` to be fully captured
    |
 LL |     let c = || { let _ = &u; 

src/test/ui/closures/2229_closure_analysis/migrations/significant_drop.fixed

@@ -23,7 +23,8 @@ fn test1_all_need_migration() {
     let t2 = (Foo(0), Foo(0));
 
     let c = || { let _ = (&t, &t1, &t2); 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1`, `t2` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -41,7 +42,8 @@ fn test2_only_precise_paths_need_migration() {
     let t2 = (Foo(0), Foo(0));
 
     let c = || { let _ = (&t, &t1); 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -57,7 +59,8 @@ fn test3_only_by_value_need_migration() {
     let t = (Foo(0), Foo(0));
     let t1 = (Foo(0), Foo(0));
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         println!("{:?}", t1.1);
@@ -74,7 +77,8 @@ fn test4_type_contains_drop_need_migration() {
     let t = ConstainsDropField(Foo(0), Foo(0));
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -89,7 +93,8 @@ fn test5_drop_non_drop_aggregate_need_migration() {
     let t = (Foo(0), Foo(0), 0i32);
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -102,7 +107,8 @@ fn test6_significant_insignificant_drop_aggregate_need_migration() {
     let t = (Foo(0), String::new());
 
     let c = || { let _ = &t; 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.1;
     };
@@ -117,7 +123,8 @@ fn test7_move_closures_non_copy_types_might_need_migration() {
     let t1 = (Foo(0), Foo(0), Foo(0));
 
     let c = move || { let _ = (&t1, &t); 
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t1`, `t` to be fully captured
         println!("{:?} {:?}", t1.1, t.1);
     };

src/test/ui/closures/2229_closure_analysis/migrations/significant_drop.rs

@@ -23,7 +23,8 @@ fn test1_all_need_migration() {
     let t2 = (Foo(0), Foo(0));
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1`, `t2` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -41,7 +42,8 @@ fn test2_only_precise_paths_need_migration() {
     let t2 = (Foo(0), Foo(0));
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t`, `t1` to be fully captured
         let _t = t.0;
         let _t1 = t1.0;
@@ -57,7 +59,8 @@ fn test3_only_by_value_need_migration() {
     let t = (Foo(0), Foo(0));
     let t1 = (Foo(0), Foo(0));
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
         println!("{:?}", t1.1);
@@ -74,7 +77,8 @@ fn test4_type_contains_drop_need_migration() {
     let t = ConstainsDropField(Foo(0), Foo(0));
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -89,7 +93,8 @@ fn test5_drop_non_drop_aggregate_need_migration() {
     let t = (Foo(0), Foo(0), 0i32);
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.0;
     };
@@ -102,7 +107,8 @@ fn test6_significant_insignificant_drop_aggregate_need_migration() {
     let t = (Foo(0), String::new());
 
     let c = || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t` to be fully captured
         let _t = t.1;
     };
@@ -117,7 +123,8 @@ fn test7_move_closures_non_copy_types_might_need_migration() {
     let t1 = (Foo(0), Foo(0), Foo(0));
 
     let c = move || {
-    //~^ ERROR: drop order affected for closure because of `capture_disjoint_fields`
+    //~^ ERROR: drop order
+    //~| NOTE: for more information, see
     //~| HELP: add a dummy let to cause `t1`, `t` to be fully captured
         println!("{:?} {:?}", t1.1, t.1);
     };

src/test/ui/closures/2229_closure_analysis/migrations/significant_drop.stderr

@@ -1,12 +1,12 @@
-error: drop order affected for closure because of `capture_disjoint_fields`
+error: drop order will change in Rust 2021
   --> $DIR/significant_drop.rs:25:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
-LL | |         let _t = t.0;
-LL | |         let _t1 = t1.0;
+LL | |
+...  |
 LL | |         let _t2 = t2.0;
 LL | |     };
    | |_____^
@@ -16,137 +16,153 @@ note: the lint level is defined here
    |
 LL | #![deny(disjoint_capture_migration)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t`, `t1`, `t2` to be fully captured
    |
 LL |     let c = || { let _ = (&t, &t1, &t2); 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         let _t1 = t1.0;
-LL |         let _t2 = t2.0;
  ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/significant_drop.rs:43:13
+error: drop order will change in Rust 2021
+  --> $DIR/significant_drop.rs:44:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
-LL | |         let _t = t.0;
-LL | |         let _t1 = t1.0;
+LL | |
+...  |
 LL | |         let _t2 = t2;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t`, `t1` to be fully captured
    |
 LL |     let c = || { let _ = (&t, &t1); 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         let _t1 = t1.0;
-LL |         let _t2 = t2;
  ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/significant_drop.rs:59:13
+error: drop order will change in Rust 2021
+  --> $DIR/significant_drop.rs:61:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |         println!("{:?}", t1.1);
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |         println!("{:?}", t1.1);
-LL |     };
-   |
+ ...
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/significant_drop.rs:76:13
+error: drop order will change in Rust 2021
+  --> $DIR/significant_drop.rs:79:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/significant_drop.rs:91:13
+error: drop order will change in Rust 2021
+  --> $DIR/significant_drop.rs:95:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.0;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.0;
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/significant_drop.rs:104:13
+error: drop order will change in Rust 2021
+  --> $DIR/significant_drop.rs:109:13
    |
 LL |       let c = || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         let _t = t.1;
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t` to be fully captured
    |
 LL |     let c = || { let _ = &t; 
 LL |
 LL |
+LL |
 LL |         let _t = t.1;
 LL |     };
    |
 
-error: drop order affected for closure because of `capture_disjoint_fields`
-  --> $DIR/significant_drop.rs:119:13
+error: drop order will change in Rust 2021
+  --> $DIR/significant_drop.rs:125:13
    |
 LL |       let c = move || {
    |  _____________^
 LL | |
 LL | |
+LL | |
 LL | |         println!("{:?} {:?}", t1.1, t.1);
 LL | |     };
    | |_____^
    |
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/disjoint-capture-in-closures.html>
 help: add a dummy let to cause `t1`, `t` to be fully captured
    |
 LL |     let c = move || { let _ = (&t1, &t); 
 LL |
 LL |
+LL |
 LL |         println!("{:?} {:?}", t1.1, t.1);
 LL |     };
    |