Merge pull request #19126 from lnicola/sync-from-rust

minor: Sync from downstream

7 files changed, 19 insertions, 78 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0038.md b/compiler/rustc_error_codes/src/error_codes/E0038.md
index 014d8c4f761..4b06395897a 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0038.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0038.md
@@ -264,15 +264,15 @@ trait Foo {
 ### Trait contains associated constants
 
 Just like static functions, associated constants aren't stored on the method
-table. If the trait or any subtrait contain an associated constant, they cannot
-be made into an object.
+table. If the trait or any subtrait contain an associated constant, they are not
+dyn compatible.
 
 ```compile_fail,E0038
 trait Foo {
     const X: i32;
 }
 
-impl Foo {}
+impl dyn Foo {}
 ```
 
 A simple workaround is to use a helper method instead:
diff --git a/compiler/rustc_error_codes/src/error_codes/E0132.md b/compiler/rustc_error_codes/src/error_codes/E0132.md
index 51258739b89..cbb14510ed7 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0132.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0132.md
@@ -1,32 +1,3 @@
-A function with the `start` attribute was declared with type parameters.
-
-Erroneous code example:
-
-```compile_fail,E0132
-#![feature(start)]
-
-#[start]
-fn f<T>() {}
-```
-
-It is not possible to declare type parameters on a function that has the `start`
-attribute. Such a function must have the following type signature (for more
-information, view [the unstable book][1]):
+#### Note: this error code is no longer emitted by the compiler.
 
-[1]: https://doc.rust-lang.org/unstable-book/language-features/start.html
-
-```
-# let _:
-fn(isize, *const *const u8) -> isize;
-```
-
-Example:
-
-```
-#![feature(start)]
-
-#[start]
-fn my_start(argc: isize, argv: *const *const u8) -> isize {
-    0
-}
-```
+A function with the `start` attribute was declared with type parameters.
diff --git a/compiler/rustc_error_codes/src/error_codes/E0138.md b/compiler/rustc_error_codes/src/error_codes/E0138.md
index 3f5eaea9f98..2e6ba546a16 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0138.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0138.md
@@ -1,25 +1,3 @@
-More than one function was declared with the `#[start]` attribute.
-
-Erroneous code example:
-
-```compile_fail,E0138
-#![feature(start)]
-
-#[start]
-fn foo(argc: isize, argv: *const *const u8) -> isize {}
+#### Note: this error code is no longer emitted by the compiler.
 
-#[start]
-fn f(argc: isize, argv: *const *const u8) -> isize {}
-// error: multiple 'start' functions
-```
-
-This error indicates that the compiler found multiple functions with the
-`#[start]` attribute. This is an error because there must be a unique entry
-point into a Rust program. Example:
-
-```
-#![feature(start)]
-
-#[start]
-fn foo(argc: isize, argv: *const *const u8) -> isize { 0 } // ok!
-```
+More than one function was declared with the `#[start]` attribute.
diff --git a/compiler/rustc_error_codes/src/error_codes/E0393.md b/compiler/rustc_error_codes/src/error_codes/E0393.md
index 50225b25163..c7260815905 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0393.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0393.md
@@ -3,12 +3,10 @@ A type parameter which references `Self` in its default value was not specified.
 Erroneous code example:
 
 ```compile_fail,E0393
-trait A<T=Self> {}
+trait A<T = Self> {}
 
-fn together_we_will_rule_the_galaxy(son: &A) {}
-// error: the type parameter `T` must be explicitly specified in an
-//        object type because its default value `Self` references the
-//        type `Self`
+fn together_we_will_rule_the_galaxy(son: &dyn A) {}
+// error: the type parameter `T` must be explicitly specified
 ```
 
 A trait object is defined over a single, fully-defined trait. With a regular
@@ -23,7 +21,7 @@ disallowed. Making the trait concrete by explicitly specifying the value of the
 defaulted parameter will fix this issue. Fixed example:
 
 ```
-trait A<T=Self> {}
+trait A<T = Self> {}
 
-fn together_we_will_rule_the_galaxy(son: &A<i32>) {} // Ok!
+fn together_we_will_rule_the_galaxy(son: &dyn A<i32>) {} // Ok!
 ```
diff --git a/compiler/rustc_error_codes/src/error_codes/E0433.md b/compiler/rustc_error_codes/src/error_codes/E0433.md
index 5a64c13c9af..36e4b66e8dc 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0433.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0433.md
@@ -19,7 +19,7 @@ If you've expected to use a crate name:
 
 ```compile_fail
 use ferris_wheel::BigO;
-// error: failed to resolve: use of undeclared crate or module `ferris_wheel`
+// error: failed to resolve: use of undeclared module or unlinked crate
 ```
 
 Make sure the crate has been added as a dependency in `Cargo.toml`.
diff --git a/compiler/rustc_error_codes/src/error_codes/E0647.md b/compiler/rustc_error_codes/src/error_codes/E0647.md
index 59bb47ba62a..e2f14b81aa6 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0647.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0647.md
@@ -1,13 +1,3 @@
-The `start` function was defined with a where clause.
-
-Erroneous code example:
+#### Note: this error code is no longer emitted by the compiler.
 
-```compile_fail,E0647
-#![feature(start)]
-
-#[start]
-fn start(_: isize, _: *const *const u8) -> isize where (): Copy {
-    //^ error: `#[start]` function is not allowed to have a where clause
-    0
-}
-```
+The `start` function was defined with a where clause.
diff --git a/compiler/rustc_error_codes/src/lib.rs b/compiler/rustc_error_codes/src/lib.rs
index 29f3277d399..0a30bdb48a0 100644
--- a/compiler/rustc_error_codes/src/lib.rs
+++ b/compiler/rustc_error_codes/src/lib.rs
@@ -24,6 +24,10 @@
 //
 // Both columns are necessary because it's not possible in Rust to create a new identifier such as
 // `E0123` from an integer literal such as `0123`, unfortunately.
+//
+// Do *not* remove entries from this list. Instead, just add a note th the corresponding markdown
+// file saying that this error is not emitted by the compiler any more (see E0001.md for an
+// example), and remove all code examples that do not build any more.
 #[macro_export]
 macro_rules! error_codes {
     ($macro:path) => (