Auto merge of #83213 - rylev:update-lints-to-errors, r=nikomatsakis

Update BARE_TRAIT_OBJECT and ELLIPSIS_INCLUSIVE_RANGE_PATTERNS to errors in Rust 2021

This addresses https://github.com/rust-lang/rust/pull/81244 by updating two lints to errors in the Rust 2021 edition.

r? `@estebank`

compiler/rustc_error_codes/src/error_codes.rs

@@ -470,6 +470,8 @@ E0778: include_str!("./error_codes/E0778.md"),
 E0779: include_str!("./error_codes/E0779.md"),
 E0780: include_str!("./error_codes/E0780.md"),
 E0781: include_str!("./error_codes/E0781.md"),
+E0782: include_str!("./error_codes/E0782.md"),
+E0783: include_str!("./error_codes/E0783.md"),
 ;
 //  E0006, // merged with E0005
 //  E0008, // cannot bind by-move into a pattern guard

compiler/rustc_error_codes/src/error_codes/E0782.md

@@ -0,0 +1,26 @@
+Trait objects must include the `dyn` keyword.
+
+Erroneous code example:
+
+```edition2021,compile_fail,E0782
+trait Foo {}
+fn test(arg: Box<Foo>) {} // error!
+```
+
+Trait objects are a way to call methods on types that are not known until
+runtime but conform to some trait.
+
+Trait objects should be formed with `Box<dyn Foo>`, but in the code above
+`dyn` is left off.
+
+This makes it harder to see that `arg` is a trait object and not a
+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!
+```
+
+This used to be allowed before edition 2021, but is now an error.

compiler/rustc_error_codes/src/error_codes/E0783.md

@@ -0,0 +1,22 @@
+The range pattern `...` is no longer allowed.
+
+Erroneous code example:
+
+```edition2021,compile_fail,E0783
+match 2u8 {
+    0...9 => println!("Got a number less than 10"), // error!
+    _ => println!("Got a number 10 or more"),
+}
+```
+
+Older Rust code using previous editions allowed `...` to stand for exclusive
+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"),
+}
+```