Add compatibility info to lints

Author: rylev

compiler/rustc_error_codes/src/error_codes/E0782.md

@@ -18,7 +18,7 @@ simply a heap allocated type called `Foo`.
 
 To fix this issue, add `dyn` before the trait name.
 
-```
+```edition2021
 trait Foo {}
 fn test(arg: Box<dyn Foo>) {} // ok!
 ```

compiler/rustc_error_codes/src/error_codes/E0783.md

@@ -14,7 +14,7 @@ ranges which are now signified using `..=`.
 
 To make this code compile replace the `...` with `..=`.
 
-```
+```edition2021
 match 2u8 {
     0..=9 => println!("Got a number less than 10"), // ok!
     _ => println!("Got a number 10 or more"),

compiler/rustc_lint/src/builtin.rs

@@ -1655,7 +1655,11 @@ declare_lint! {
     /// [`..` range expression]: https://doc.rust-lang.org/reference/expressions/range-expr.html
     pub ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
     Warn,
-    "`...` range patterns are deprecated"
+    "`...` range patterns are deprecated",
+    @future_incompatible = FutureIncompatibleInfo {
+        reference: "issue #80165 <https://github.com/rust-lang/rust/issues/80165>",
+        edition: Some(Edition::Edition2021),
+    };
 }
 
 #[derive(Default)]

compiler/rustc_lint_defs/src/builtin.rs

@@ -1618,7 +1618,11 @@ declare_lint! {
     /// [`impl Trait`]: https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
     pub BARE_TRAIT_OBJECTS,
     Warn,
-    "suggest using `dyn Trait` for trait objects"
+    "suggest using `dyn Trait` for trait objects",
+    @future_incompatible = FutureIncompatibleInfo {
+        reference: "issue #80165 <https://github.com/rust-lang/rust/issues/80165>",
+        edition: Some(Edition::Edition2021),
+    };
 }
 
 declare_lint! {

src/test/ui/dyn-keyword/dyn-2018-edition-lint.rs

@@ -0,0 +1,16 @@
+// edition:2018
+#[deny(bare_trait_objects)]
+
+fn function(x: &SomeTrait, y: Box<SomeTrait>) {
+    //~^ ERROR trait objects without an explicit `dyn` are deprecated
+    //~| WARN this was previously accepted
+    //~| ERROR trait objects without an explicit `dyn` are deprecated
+    //~| WARN this was previously accepted
+    let _x: &SomeTrait = todo!();
+    //~^ ERROR trait objects without an explicit `dyn` are deprecated
+    //~| WARN this was previously accepted
+}
+
+trait SomeTrait {}
+
+fn main() {}

src/test/ui/dyn-keyword/dyn-2018-edition-lint.stderr

@@ -0,0 +1,34 @@
+error: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/dyn-2018-edition-lint.rs:4:17
+   |
+LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
+   |                 ^^^^^^^^^ help: use `dyn`: `dyn SomeTrait`
+   |
+note: the lint level is defined here
+  --> $DIR/dyn-2018-edition-lint.rs:2:8
+   |
+LL | #[deny(bare_trait_objects)]
+   |        ^^^^^^^^^^^^^^^^^^
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2021 edition!
+   = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>
+
+error: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/dyn-2018-edition-lint.rs:4:35
+   |
+LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
+   |                                   ^^^^^^^^^ help: use `dyn`: `dyn SomeTrait`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2021 edition!
+   = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>
+
+error: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/dyn-2018-edition-lint.rs:9:14
+   |
+LL |     let _x: &SomeTrait = todo!();
+   |              ^^^^^^^^^ help: use `dyn`: `dyn SomeTrait`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2021 edition!
+   = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>
+
+error: aborting due to 3 previous errors
+