Further improve error message for E0081

Multiple duplicate assignments of the same discriminant are now reported
in the samme error. We now point out the incrementation start point for
discriminants that are not explicitly assigned that are also duplicates.
Removed old test related to E0081 that is now covered by error-codes/E0081.rs.
Also refactored parts of the `check_enum` function.

2 files changed, 4 insertions, 4 deletions

diff --git a/src/test/ui/enum/enum-discrim-autosizing.rs b/src/test/ui/enum/enum-discrim-autosizing.rs
index 27fab1bb505..fc94d281c77 100644
--- a/src/test/ui/enum/enum-discrim-autosizing.rs
+++ b/src/test/ui/enum/enum-discrim-autosizing.rs
@@ -6,9 +6,9 @@
 enum Eu64 {
     //~^ ERROR discriminant value `0` assigned more than once
     Au64 = 0,
-    //~^NOTE first assignment of `0`
+    //~^NOTE `0` assigned here
     Bu64 = 0x8000_0000_0000_0000
-    //~^NOTE second assignment of `0` (overflowed from `9223372036854775808`)
+    //~^NOTE `0` (overflowed from `9223372036854775808`) assigned here
 }
 
 fn main() {}
diff --git a/src/test/ui/enum/enum-discrim-autosizing.stderr b/src/test/ui/enum/enum-discrim-autosizing.stderr
index eacea86d67e..be3d7c64e28 100644
--- a/src/test/ui/enum/enum-discrim-autosizing.stderr
+++ b/src/test/ui/enum/enum-discrim-autosizing.stderr
@@ -5,10 +5,10 @@ LL | enum Eu64 {
    | ^^^^^^^^^
 LL |
 LL |     Au64 = 0,
-   |            - first assignment of `0`
+   |            - `0` assigned here
 LL |
 LL |     Bu64 = 0x8000_0000_0000_0000
-   |            --------------------- second assignment of `0` (overflowed from `9223372036854775808`)
+   |            --------------------- `0` (overflowed from `9223372036854775808`) assigned here
 
 error: aborting due to previous error