simplify strip attrs

crates/ra_syntax/src/ast/edit.rs

@@ -1,14 +1,16 @@
 //! This module contains functions for editing syntax trees. As the trees are
 //! immutable, all function here return a fresh copy of the tree, instead of
 //! doing an in-place modification.
+use std::{iter, ops::RangeInclusive};
 
 use arrayvec::ArrayVec;
-use std::ops::RangeInclusive;
 
 use crate::{
     algo,
     ast::{self, make, AstNode},
     InsertPosition, SyntaxElement,
+    SyntaxKind::{ATTR, COMMENT, WHITESPACE},
+    SyntaxNode,
 };
 
 impl ast::FnDef {
@@ -31,6 +33,23 @@ impl ast::FnDef {
     }
 }
 
+pub fn strip_attrs_and_docs<N: ast::AttrsOwner>(node: N) -> N {
+    N::cast(strip_attrs_and_docs_inner(node.syntax().clone())).unwrap()
+}
+
+fn strip_attrs_and_docs_inner(mut node: SyntaxNode) -> SyntaxNode {
+    while let Some(start) =
+        node.children_with_tokens().find(|it| it.kind() == ATTR || it.kind() == COMMENT)
+    {
+        let end = match &start.next_sibling_or_token() {
+            Some(el) if el.kind() == WHITESPACE => el.clone(),
+            Some(_) | None => start.clone(),
+        };
+        node = algo::replace_children(&node, RangeInclusive::new(start, end), &mut iter::empty());
+    }
+    node
+}
+
 #[must_use]
 fn insert_children<N: AstNode>(
     parent: &N,

crates/ra_syntax/src/ast/extensions.rs

@@ -4,7 +4,7 @@
 use itertools::Itertools;
 
 use crate::{
-    ast::{self, child_opt, children, AstNode, SyntaxNode},
+    ast::{self, child_opt, children, AstChildren, AstNode, SyntaxNode},
     SmolStr, SyntaxElement,
     SyntaxKind::*,
     SyntaxToken, T,
@@ -203,6 +203,16 @@ impl ast::ImplBlock {
     }
 }
 
+impl ast::AttrsOwner for ast::ImplItem {
+    fn attrs(&self) -> AstChildren<ast::Attr> {
+        match self {
+            ast::ImplItem::FnDef(it) => it.attrs(),
+            ast::ImplItem::TypeAliasDef(it) => it.attrs(),
+            ast::ImplItem::ConstDef(it) => it.attrs(),
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum StructKind {
     Tuple(ast::TupleFieldDefList),