Auto merge of #68363 - Dylan-DPC:rollup-33enndv, r=Dylan-DPC

Rollup of 3 pull requests

Successful merges:

 - #67682 ([const-prop] Remove useless typedef)
 - #68247 (Clean up err codes)
 - #68348 (Make iter::Empty<T> Send and Sync for any T)

Failed merges:

r? @ghost

2 files changed, 15 insertions, 7 deletions

diff --git a/src/librustc_error_codes/error_codes/E0195.md b/src/librustc_error_codes/error_codes/E0195.md
index 3606521020a..b8c313d412e 100644
--- a/src/librustc_error_codes/error_codes/E0195.md
+++ b/src/librustc_error_codes/error_codes/E0195.md
@@ -1,4 +1,5 @@
-Your method's lifetime parameters do not match the trait declaration.
+The lifetime parameters of the method do not match the trait declaration.
+
 Erroneous code example:
 
 ```compile_fail,E0195
@@ -16,7 +17,7 @@ impl Trait for Foo {
 }
 ```
 
-The lifetime constraint `'b` for bar() implementation does not match the
+The lifetime constraint `'b` for `bar()` implementation does not match the
 trait declaration. Ensure lifetime declarations match exactly in both trait
 declaration and implementation. Example:
 
diff --git a/src/librustc_error_codes/error_codes/E0197.md b/src/librustc_error_codes/error_codes/E0197.md
index 0d91157e572..c142b8f3664 100644
--- a/src/librustc_error_codes/error_codes/E0197.md
+++ b/src/librustc_error_codes/error_codes/E0197.md
@@ -1,13 +1,20 @@
+An inherent implementation was marked unsafe.
+
+Erroneous code example:
+
+```compile_fail,E0197
+struct Foo;
+
+unsafe impl Foo { } // error!
+```
+
 Inherent implementations (one that do not implement a trait but provide
 methods associated with a type) are always safe because they are not
 implementing an unsafe trait. Removing the `unsafe` keyword from the inherent
 implementation will resolve this error.
 
-```compile_fail,E0197
+```
 struct Foo;
 
-// this will cause this error
-unsafe impl Foo { }
-// converting it to this will fix it
-impl Foo { }
+impl Foo { } // ok!
 ```