Merge #9979

9979: fix: Incorrect up-mapping for tokens in derive attributes r=Veykril a=Veykril

Merely detaching the attributes causes incorrect spans to appear when mapping tokens up as the token ids resolve to the ranges of the stripped item so all the text ranges of its tokens are actually lower than the non-stripped ones.

Same fix as with attributes can be applied here, just replace the derive attribute with an equal amount of whitespace.

Fixes #9387

Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

Author: bors[bot]

crates/hir_expand/src/input.rs

@@ -40,7 +40,7 @@ fn remove_derives_up_to(item: ast::Item, attr_index: usize) -> ast::Item {
             attr.path().and_then(|path| path.as_single_segment()).and_then(|seg| seg.name_ref())
         {
             if name.as_name() == name![derive] {
-                attr.syntax().detach();
+                replace_attr(&item, &attr);
             }
         }
     }
@@ -54,10 +54,14 @@ fn remove_attr_invoc(item: ast::Item, attr_index: usize) -> ast::Item {
         .attrs()
         .nth(attr_index)
         .unwrap_or_else(|| panic!("cannot find attribute #{}", attr_index));
+    replace_attr(&item, &attr);
+    item
+}
+
+fn replace_attr(item: &ast::Item, attr: &ast::Attr) {
     let syntax_index = attr.syntax().index();
     let ws = make::tokens::whitespace(&" ".repeat(u32::from(attr.syntax().text().len()) as usize));
     item.syntax().splice_children(syntax_index..syntax_index + 1, vec![ws.into()]);
-    item
 }
 
 #[cfg(test)]
@@ -78,7 +82,9 @@ mod tests {
         assert_eq!(items.len(), 1);
 
         let item = remove_derives_up_to(items.pop().unwrap(), attr);
-        expect.assert_eq(&item.to_string());
+        let res: String =
+            item.syntax().children_with_tokens().map(|e| format!("{:?}\n", e)).collect();
+        expect.assert_eq(&res);
     }
 
     #[test]
@@ -95,13 +101,20 @@ struct A {
 }
         "#,
             expect![[r#"
-#[allow(unused)]
-
-
-#[derive(Clone)]
-struct A {
-    bar: u32
-}"#]],
+                Node(ATTR@0..16)
+                Token(WHITESPACE@16..17 "\n")
+                Token(WHITESPACE@17..32 "               ")
+                Token(WHITESPACE@32..33 "\n")
+                Token(WHITESPACE@33..49 "                ")
+                Token(WHITESPACE@49..50 "\n")
+                Node(ATTR@50..66)
+                Token(WHITESPACE@66..67 "\n")
+                Token(STRUCT_KW@67..73 "struct")
+                Token(WHITESPACE@73..74 " ")
+                Node(NAME@74..75)
+                Token(WHITESPACE@75..76 " ")
+                Node(RECORD_FIELD_LIST@76..92)
+            "#]],
         );
     }
 }