suggest removing a semicolon after derive attributes

use current token span

compiler/rustc_parse/src/parser/item.rs

@@ -449,6 +449,16 @@ impl<'a> Parser<'a> {
         if end.is_doc_comment() {
             err.span_label(end.span, "this doc comment doesn't document anything");
         }
+        if end.meta_kind().is_some() {
+            if self.token.kind == TokenKind::Semi {
+                err.span_suggestion_verbose(
+                    self.token.span,
+                    "consider removing this semicolon",
+                    String::new(),
+                    Applicability::MaybeIncorrect,
+                );
+            }
+        }
         if let [.., penultimate, _] = attrs {
             err.span_label(start.span.to(penultimate.span), "other attributes here");
         }

src/test/ui/parser/attr-with-a-semicolon.rs

@@ -0,0 +1,4 @@
+#[derive(Debug, Clone)]; //~ERROR expected item after attributes
+struct Foo;
+
+fn main() {}

src/test/ui/parser/attr-with-a-semicolon.stderr

@@ -0,0 +1,14 @@
+error: expected item after attributes
+  --> $DIR/attr-with-a-semicolon.rs:1:1
+   |
+LL | #[derive(Debug, Clone)];
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider removing this semicolon
+   |
+LL - #[derive(Debug, Clone)];
+LL + #[derive(Debug, Clone)]
+   | 
+
+error: aborting due to previous error
+