Change error into E0585

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>

Author: xizheyin

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -710,6 +710,13 @@ impl<'a> Parser<'a> {
             } else {
                 // For fine-grained suggestions, we should suggest to add a comma before the doc comment
                 // like `expr, //!val`
+                err.cancel();
+                err = self.dcx().struct_span_err(
+                    self.token.span,
+                    "found a documentation comment that doesn't document anything",
+                );
+                err.code(rustc_errors::E0585);
+                err.span_label(self.token.span, "this doc comment doesn't document anything");
                 err.span_suggestion_verbose(
                     self.prev_token.span.shrink_to_hi(),
                     "missing `,` before the doc comment",

tests/ui/parser/doc-comment-after-missing-comma-issue-142311.rs

@@ -8,11 +8,11 @@ enum Foo {
     /// Like the noise a sheep makes
     Bar
     /// Like where people drink
-    //~^ ERROR expected one of `(`, `,`, `=`, `{`, or `}`, found doc comment `/// Like where people drink`
+    //~^ ERROR found a documentation comment that doesn't document anything [E0585]
     Baa///xxxxxx
-    //~^ ERROR expected one of `(`, `,`, `=`, `{`, or `}`, found doc comment `///xxxxxx`
+    //~^ ERROR found a documentation comment that doesn't document anything [E0585]
     Baz///xxxxxx
-    //~^ ERROR expected one of `(`, `,`, `=`, `{`, or `}`, found doc comment `///xxxxxx`
+    //~^ ERROR found a documentation comment that doesn't document anything [E0585]
 }
 
 fn main() {}

tests/ui/parser/doc-comment-after-missing-comma-issue-142311.stderr

@@ -1,32 +1,41 @@
-error: expected one of `(`, `,`, `=`, `{`, or `}`, found doc comment `/// Like where people drink`
+error[E0585]: found a documentation comment that doesn't document anything
   --> $DIR/doc-comment-after-missing-comma-issue-142311.rs:10:5
    |
 LL |     Bar
    |        - expected one of `(`, `,`, `=`, `{`, or `}`
 LL |     /// Like where people drink
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ unexpected token
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     |
+   |     this doc comment doesn't document anything
+   |     unexpected token
    |
 help: missing `,` before the doc comment
    |
 LL |     Bar, 
    |        +
 
-error: expected one of `(`, `,`, `=`, `{`, or `}`, found doc comment `///xxxxxx`
+error[E0585]: found a documentation comment that doesn't document anything
   --> $DIR/doc-comment-after-missing-comma-issue-142311.rs:12:8
    |
 LL |     Baa///xxxxxx
-   |        ^^^^^^^^^ expected one of `(`, `,`, `=`, `{`, or `}`
+   |        ^^^^^^^^^
+   |        |
+   |        this doc comment doesn't document anything
+   |        expected one of `(`, `,`, `=`, `{`, or `}`
    |
 help: missing `,` before the doc comment
    |
 LL |     Baa, ///xxxxxx
    |        +
 
-error: expected one of `(`, `,`, `=`, `{`, or `}`, found doc comment `///xxxxxx`
+error[E0585]: found a documentation comment that doesn't document anything
   --> $DIR/doc-comment-after-missing-comma-issue-142311.rs:14:8
    |
 LL |     Baz///xxxxxx
-   |        ^^^^^^^^^ expected one of `(`, `,`, `=`, `{`, or `}`
+   |        ^^^^^^^^^
+   |        |
+   |        this doc comment doesn't document anything
+   |        expected one of `(`, `,`, `=`, `{`, or `}`
    |
    = help: doc comments must come before what they document, if a comment was intended use `//`
    = help: enum variants can be `Variant`, `Variant = <integer>`, `Variant(Type, ..., TypeN)` or `Variant { fields: Types }`
@@ -37,3 +46,4 @@ LL |     Baz, ///xxxxxx
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0585`.