From dccaa5e45e9baaa2d286353a7499a89af1669e42 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 2 Oct 2018 17:50:56 +0300
Subject: [PATCH 1/3] use aliases

---
 crates/ra_syntax/src/yellow/mod.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/ra_syntax/src/yellow/mod.rs b/crates/ra_syntax/src/yellow/mod.rs
index c621b1d6a3..2c57d8b418 100644
--- a/crates/ra_syntax/src/yellow/mod.rs
+++ b/crates/ra_syntax/src/yellow/mod.rs
@@ -53,12 +53,12 @@ impl<R: TreeRoot<RaTypes>> Hash for SyntaxNode<R> {
     }
 }
 
-impl SyntaxNode<OwnedRoot> {
+impl SyntaxNode {
     pub(crate) fn new(green: GreenNode, errors: Vec<SyntaxError>) -> SyntaxNode {
         SyntaxNode(::rowan::SyntaxNode::new(green, errors))
     }
 }
-impl<'a> SyntaxNode<RefRoot<'a>> {
+impl<'a> SyntaxNodeRef<'a> {
     pub fn leaf_text(self) -> Option<&'a SmolStr> {
         self.0.leaf_text()
     }

From d323c81d5cc6a198239285abcede2166181d8f39 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 2 Oct 2018 18:02:57 +0300
Subject: [PATCH 2/3] make ancestors and descendants inherent

---
 crates/ra_editor/src/code_actions.rs       |  5 ++---
 crates/ra_editor/src/completion.rs         | 13 ++++++-------
 crates/ra_editor/src/extend_selection.rs   |  4 ++--
 crates/ra_editor/src/folding_ranges.rs     |  8 +++-----
 crates/ra_editor/src/lib.rs                | 10 +++++-----
 crates/ra_editor/src/scope/fn_scope.rs     |  6 +++---
 crates/ra_editor/src/symbols.rs            |  4 ++--
 crates/ra_editor/src/typing.rs             |  3 +--
 crates/ra_syntax/src/algo/mod.rs           |  8 ++------
 crates/ra_syntax/src/algo/walk.rs          |  6 ------
 crates/ra_syntax/src/reparsing.rs          |  2 +-
 crates/ra_syntax/src/utils.rs              |  4 ++--
 crates/ra_syntax/src/yellow/mod.rs         |  9 +++++++++
 crates/ra_syntax/src/yellow/syntax_text.rs |  4 ++--
 14 files changed, 40 insertions(+), 46 deletions(-)

diff --git a/crates/ra_editor/src/code_actions.rs b/crates/ra_editor/src/code_actions.rs
index 83f7956d29..b0f0d8f1d0 100644
--- a/crates/ra_editor/src/code_actions.rs
+++ b/crates/ra_editor/src/code_actions.rs
@@ -9,7 +9,6 @@ use ra_syntax::{
         Direction, siblings,
         find_leaf_at_offset,
         find_covering_node,
-        ancestors,
     },
 };
 
@@ -101,8 +100,8 @@ pub fn add_impl<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce() ->
 
 pub fn introduce_variable<'a>(file: &'a File, range: TextRange) -> Option<impl FnOnce() -> LocalEdit + 'a> {
     let node = find_covering_node(file.syntax(), range);
-    let expr = ancestors(node).filter_map(ast::Expr::cast).next()?;
-    let anchor_stmt = ancestors(expr.syntax()).filter_map(ast::Stmt::cast).next()?;
+    let expr = node.ancestors().filter_map(ast::Expr::cast).next()?;
+    let anchor_stmt = expr.syntax().ancestors().filter_map(ast::Stmt::cast).next()?;
     let indent = anchor_stmt.syntax().prev_sibling()?;
     if indent.kind() != WHITESPACE {
         return None;
diff --git a/crates/ra_editor/src/completion.rs b/crates/ra_editor/src/completion.rs
index ff9de20d38..62a63fb044 100644
--- a/crates/ra_editor/src/completion.rs
+++ b/crates/ra_editor/src/completion.rs
@@ -4,7 +4,6 @@ use ra_syntax::{
     File, TextUnit, AstNode, SyntaxNodeRef, SyntaxKind::*,
     ast::{self, LoopBodyOwner, ModuleItemOwner},
     algo::{
-        ancestors,
         visit::{visitor, Visitor, visitor_ctx, VisitorCtx},
     },
     text_utils::is_subrange,
@@ -59,7 +58,7 @@ fn complete_name_ref(file: &File, name_ref: ast::NameRef, acc: &mut Vec<Completi
         return;
     }
     let mut visited_fn = false;
-    for node in ancestors(name_ref.syntax()) {
+    for node in name_ref.syntax().ancestors() {
         if let Some(items) = visitor()
             .visit::<ast::Root, _>(|it| Some(it.items()))
             .visit::<ast::Module, _>(|it| Some(it.item_list()?.items()))
@@ -92,7 +91,7 @@ fn complete_name_ref(file: &File, name_ref: ast::NameRef, acc: &mut Vec<Completi
 
 fn param_completions(ctx: SyntaxNodeRef, acc: &mut Vec<CompletionItem>) {
     let mut params = HashMap::new();
-    for node in ancestors(ctx) {
+    for node in ctx.ancestors() {
         let _ = visitor_ctx(&mut params)
             .visit::<ast::Root, _>(process)
             .visit::<ast::ItemList, _>(process)
@@ -123,7 +122,7 @@ fn param_completions(ctx: SyntaxNodeRef, acc: &mut Vec<CompletionItem>) {
 }
 
 fn is_node<'a, N: AstNode<'a>>(node: SyntaxNodeRef<'a>) -> bool {
-    match ancestors(node).filter_map(N::cast).next() {
+    match node.ancestors().filter_map(N::cast).next() {
         None => false,
         Some(n) => n.syntax().range() == node.range(),
     }
@@ -152,7 +151,7 @@ fn complete_expr_keywords(file: &File, fn_def: ast::FnDef, name_ref: ast::NameRe
 }
 
 fn is_in_loop_body(name_ref: ast::NameRef) -> bool {
-    for node in ancestors(name_ref.syntax()) {
+    for node in name_ref.syntax().ancestors() {
         if node.kind() == FN_DEF || node.kind() == LAMBDA_EXPR {
             break;
         }
@@ -171,7 +170,7 @@ fn is_in_loop_body(name_ref: ast::NameRef) -> bool {
 }
 
 fn complete_return(fn_def: ast::FnDef, name_ref: ast::NameRef) -> Option<CompletionItem> {
-    // let is_last_in_block = ancestors(name_ref.syntax()).filter_map(ast::Expr::cast)
+    // let is_last_in_block = name_ref.syntax().ancestors().filter_map(ast::Expr::cast)
     //     .next()
     //     .and_then(|it| it.syntax().parent())
     //     .and_then(ast::Block::cast)
@@ -181,7 +180,7 @@ fn complete_return(fn_def: ast::FnDef, name_ref: ast::NameRef) -> Option<Complet
     //     return None;
     // }
 
-    let is_stmt = match ancestors(name_ref.syntax()).filter_map(ast::ExprStmt::cast).next() {
+    let is_stmt = match name_ref.syntax().ancestors().filter_map(ast::ExprStmt::cast).next() {
         None => false,
         Some(expr_stmt) => expr_stmt.syntax().range() == name_ref.syntax().range()
     };
diff --git a/crates/ra_editor/src/extend_selection.rs b/crates/ra_editor/src/extend_selection.rs
index dc914a26ad..2f8a04b2b3 100644
--- a/crates/ra_editor/src/extend_selection.rs
+++ b/crates/ra_editor/src/extend_selection.rs
@@ -1,7 +1,7 @@
 use ra_syntax::{
     File, TextRange, SyntaxNodeRef, TextUnit,
     SyntaxKind::*,
-    algo::{find_leaf_at_offset, LeafAtOffset, find_covering_node, ancestors, Direction, siblings},
+    algo::{find_leaf_at_offset, LeafAtOffset, find_covering_node, Direction, siblings},
 };
 
 pub fn extend_selection(file: &File, range: TextRange) -> Option<TextRange> {
@@ -30,7 +30,7 @@ pub(crate) fn extend(root: SyntaxNodeRef, range: TextRange) -> Option<TextRange>
         }
     }
 
-    match ancestors(node).skip_while(|n| n.range() == range).next() {
+    match node.ancestors().skip_while(|n| n.range() == range).next() {
         None => None,
         Some(parent) => Some(parent.range()),
     }
diff --git a/crates/ra_editor/src/folding_ranges.rs b/crates/ra_editor/src/folding_ranges.rs
index 817da28d1a..892aaf97be 100644
--- a/crates/ra_editor/src/folding_ranges.rs
+++ b/crates/ra_editor/src/folding_ranges.rs
@@ -3,7 +3,7 @@ use std::collections::HashSet;
 use ra_syntax::{
     File, TextRange, SyntaxNodeRef,
     SyntaxKind,
-    algo::{walk, Direction, siblings},
+    algo::{Direction, siblings},
 };
 
 #[derive(Debug, PartialEq, Eq)]
@@ -19,12 +19,10 @@ pub struct Fold {
 }
 
 pub fn folding_ranges(file: &File) -> Vec<Fold> {
-    let syntax = file.syntax();
-
     let mut res = vec![];
     let mut visited = HashSet::new();
 
-    for node in walk::preorder(syntax) {
+    for node in file.syntax().descendants() {
         if visited.contains(&node) {
             continue;
         }
@@ -139,4 +137,4 @@ fn main() {
     }
 
 
-}
\ No newline at end of file
+}
diff --git a/crates/ra_editor/src/lib.rs b/crates/ra_editor/src/lib.rs
index de929d73a6..a93924e005 100644
--- a/crates/ra_editor/src/lib.rs
+++ b/crates/ra_editor/src/lib.rs
@@ -21,7 +21,7 @@ mod test_utils;
 use ra_syntax::{
     File, TextUnit, TextRange, SyntaxNodeRef,
     ast::{self, AstNode, NameOwner},
-    algo::{walk, find_leaf_at_offset, ancestors},
+    algo::find_leaf_at_offset,
     SyntaxKind::{self, *},
 };
 pub use ra_syntax::AtomEdit;
@@ -86,7 +86,7 @@ pub fn matching_brace(file: &File, offset: TextUnit) -> Option<TextUnit> {
 
 pub fn highlight(file: &File) -> Vec<HighlightedRange> {
     let mut res = Vec::new();
-    for node in walk::preorder(file.syntax()) {
+    for node in file.syntax().descendants() {
         let tag = match node.kind() {
             ERROR => "error",
             COMMENT | DOC_COMMENT => "comment",
@@ -110,7 +110,7 @@ pub fn highlight(file: &File) -> Vec<HighlightedRange> {
 pub fn diagnostics(file: &File) -> Vec<Diagnostic> {
     let mut res = Vec::new();
 
-    for node in walk::preorder(file.syntax()) {
+    for node in file.syntax().descendants() {
         if node.kind() == ERROR {
             res.push(Diagnostic {
                 range: node.range(),
@@ -130,7 +130,7 @@ pub fn syntax_tree(file: &File) -> String {
 }
 
 pub fn runnables(file: &File) -> Vec<Runnable> {
-    walk::preorder(file.syntax())
+    file.syntax().descendants()
         .filter_map(ast::FnDef::cast)
         .filter_map(|f| {
             let name = f.name()?.text();
@@ -159,7 +159,7 @@ pub fn find_node_at_offset<'a, N: AstNode<'a>>(
     let leaf = leaves.clone()
         .find(|leaf| !leaf.kind().is_trivia())
         .or_else(|| leaves.right_biased())?;
-    ancestors(leaf)
+    leaf.ancestors()
         .filter_map(N::cast)
         .next()
 }
diff --git a/crates/ra_editor/src/scope/fn_scope.rs b/crates/ra_editor/src/scope/fn_scope.rs
index 3ae5276a22..eddd874956 100644
--- a/crates/ra_editor/src/scope/fn_scope.rs
+++ b/crates/ra_editor/src/scope/fn_scope.rs
@@ -6,7 +6,7 @@ use std::{
 use ra_syntax::{
     SyntaxNodeRef, SyntaxNode, SmolStr, AstNode,
     ast::{self, NameOwner, LoopBodyOwner, ArgListOwner},
-    algo::{ancestors, generate, walk::preorder}
+    algo::{generate}
 };
 
 type ScopeId = usize;
@@ -51,7 +51,7 @@ impl FnScopes {
         res
     }
     fn add_bindings(&mut self, scope: ScopeId, pat: ast::Pat) {
-        let entries = preorder(pat.syntax())
+        let entries = pat.syntax().descendants()
             .filter_map(ast::BindPat::cast)
             .filter_map(ScopeEntry::new);
         self.scopes[scope].entries.extend(entries);
@@ -66,7 +66,7 @@ impl FnScopes {
         self.scope_for.insert(node.owned(), scope);
     }
     fn scope_for(&self, node: SyntaxNodeRef) -> Option<ScopeId> {
-        ancestors(node)
+        node.ancestors()
             .filter_map(|it| self.scope_for.get(&it.owned()).map(|&scope| scope))
             .next()
     }
diff --git a/crates/ra_editor/src/symbols.rs b/crates/ra_editor/src/symbols.rs
index 9179841772..e5cc5ca284 100644
--- a/crates/ra_editor/src/symbols.rs
+++ b/crates/ra_editor/src/symbols.rs
@@ -3,7 +3,7 @@ use ra_syntax::{
     ast::{self, NameOwner},
     algo::{
         visit::{visitor, Visitor},
-        walk::{walk, WalkEvent, preorder},
+        walk::{walk, WalkEvent},
     },
 };
 use TextRange;
@@ -25,7 +25,7 @@ pub struct FileSymbol {
 }
 
 pub fn file_symbols(file: &File) -> Vec<FileSymbol> {
-    preorder(file.syntax())
+    file.syntax().descendants()
         .filter_map(to_symbol)
         .collect()
 }
diff --git a/crates/ra_editor/src/typing.rs b/crates/ra_editor/src/typing.rs
index 0f4e7e0d02..5120769418 100644
--- a/crates/ra_editor/src/typing.rs
+++ b/crates/ra_editor/src/typing.rs
@@ -4,7 +4,6 @@ use ra_syntax::{
     TextUnit, TextRange, SyntaxNodeRef, File, AstNode, SyntaxKind,
     ast,
     algo::{
-        walk::preorder,
         find_covering_node,
     },
     text_utils::{intersect, contains_offset_nonstrict},
@@ -33,7 +32,7 @@ pub fn join_lines(file: &File, range: TextRange) -> LocalEdit {
     };
     let node = find_covering_node(file.syntax(), range);
     let mut edit = EditBuilder::new();
-    for node in preorder(node) {
+    for node in node.descendants() {
         let text = match node.leaf_text() {
             Some(text) => text,
             None => continue,
diff --git a/crates/ra_syntax/src/algo/mod.rs b/crates/ra_syntax/src/algo/mod.rs
index 8de44c5861..3716a6000f 100644
--- a/crates/ra_syntax/src/algo/mod.rs
+++ b/crates/ra_syntax/src/algo/mod.rs
@@ -94,10 +94,6 @@ pub fn find_covering_node(root: SyntaxNodeRef, range: TextRange) -> SyntaxNodeRe
     common_ancestor(left, right)
 }
 
-pub fn ancestors<'a>(node: SyntaxNodeRef<'a>) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
-    generate(Some(node), |&node| node.parent())
-}
-
 #[derive(Debug)]
 pub enum Direction {
     Forward,
@@ -115,8 +111,8 @@ pub fn siblings<'a>(
 }
 
 fn common_ancestor<'a>(n1: SyntaxNodeRef<'a>, n2: SyntaxNodeRef<'a>) -> SyntaxNodeRef<'a> {
-    for p in ancestors(n1) {
-        if ancestors(n2).any(|a| a == p) {
+    for p in n1.ancestors() {
+        if n2.ancestors().any(|a| a == p) {
             return p;
         }
     }
diff --git a/crates/ra_syntax/src/algo/walk.rs b/crates/ra_syntax/src/algo/walk.rs
index 536ee705fb..8e294d965b 100644
--- a/crates/ra_syntax/src/algo/walk.rs
+++ b/crates/ra_syntax/src/algo/walk.rs
@@ -3,12 +3,6 @@ use {
     algo::generate,
 };
 
-pub fn preorder<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = SyntaxNodeRef<'a>> {
-    walk(root).filter_map(|event| match event {
-        WalkEvent::Enter(node) => Some(node),
-        WalkEvent::Exit(_) => None,
-    })
-}
 
 #[derive(Debug, Copy, Clone)]
 pub enum WalkEvent<'a> {
diff --git a/crates/ra_syntax/src/reparsing.rs b/crates/ra_syntax/src/reparsing.rs
index e3c200d1e1..dcafd2c407 100644
--- a/crates/ra_syntax/src/reparsing.rs
+++ b/crates/ra_syntax/src/reparsing.rs
@@ -112,7 +112,7 @@ fn find_reparsable_node<'node>(
     range: TextRange,
 ) -> Option<(SyntaxNodeRef<'node>, fn(&mut Parser))> {
     let node = algo::find_covering_node(node, range);
-    return algo::ancestors(node)
+    return node.ancestors()
         .filter_map(|node| reparser(node).map(|r| (node, r)))
         .next();
 
diff --git a/crates/ra_syntax/src/utils.rs b/crates/ra_syntax/src/utils.rs
index 8bc5f0e24c..e274f7471f 100644
--- a/crates/ra_syntax/src/utils.rs
+++ b/crates/ra_syntax/src/utils.rs
@@ -1,6 +1,6 @@
 use std::fmt::Write;
 use {
-    algo::walk::{preorder, walk, WalkEvent},
+    algo::walk::{walk, WalkEvent},
     SyntaxKind, File, SyntaxNodeRef
 };
 
@@ -56,7 +56,7 @@ pub fn check_fuzz_invariants(text: &str) {
 
 pub(crate) fn validate_block_structure(root: SyntaxNodeRef) {
     let mut stack = Vec::new();
-    for node in preorder(root) {
+    for node in root.descendants() {
         match node.kind() {
             SyntaxKind::L_CURLY => {
                 stack.push(node)
diff --git a/crates/ra_syntax/src/yellow/mod.rs b/crates/ra_syntax/src/yellow/mod.rs
index 2c57d8b418..95d277a2fc 100644
--- a/crates/ra_syntax/src/yellow/mod.rs
+++ b/crates/ra_syntax/src/yellow/mod.rs
@@ -62,6 +62,15 @@ impl<'a> SyntaxNodeRef<'a> {
     pub fn leaf_text(self) -> Option<&'a SmolStr> {
         self.0.leaf_text()
     }
+    pub fn ancestors(self) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
+        ::algo::generate(Some(self), |&node| node.parent())
+    }
+    pub fn descendants(self) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
+        ::algo::walk::walk(self).filter_map(|event| match event {
+            ::algo::walk::WalkEvent::Enter(node) => Some(node),
+            ::algo::walk::WalkEvent::Exit(_) => None,
+        })
+    }
 }
 
 impl<R: TreeRoot<RaTypes>> SyntaxNode<R> {
diff --git a/crates/ra_syntax/src/yellow/syntax_text.rs b/crates/ra_syntax/src/yellow/syntax_text.rs
index affd7f9c7d..0db1049de9 100644
--- a/crates/ra_syntax/src/yellow/syntax_text.rs
+++ b/crates/ra_syntax/src/yellow/syntax_text.rs
@@ -4,7 +4,6 @@ use std::{
 
 use {
     SyntaxNodeRef, TextRange, TextUnit,
-    algo::walk::preorder,
     text_utils::{intersect, contains_offset_nonstrict},
 };
 
@@ -23,7 +22,8 @@ impl<'a> SyntaxText<'a> {
     }
     pub fn chunks(&self) -> impl Iterator<Item=&'a str> {
         let range = self.range;
-        preorder(self.node)
+        self.node
+            .descendants()
             .filter_map(move |node| {
                 let text = node.leaf_text()?;
                 let range = intersect(range, node.range())?;

From 1a2a8dec14ec04ea8eeccae99fd885e7a280e45b Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 2 Oct 2018 18:14:33 +0300
Subject: [PATCH 3/3] Make siblings an inherent method

---
 crates/ra_editor/src/code_actions.rs     | 13 ++++++-------
 crates/ra_editor/src/extend_selection.rs | 16 ++++++++--------
 crates/ra_editor/src/folding_ranges.rs   |  4 ++--
 crates/ra_syntax/src/algo/mod.rs         | 16 ----------------
 crates/ra_syntax/src/lib.rs              |  2 +-
 crates/ra_syntax/src/yellow/mod.rs       | 13 +++++++++++++
 6 files changed, 30 insertions(+), 34 deletions(-)

diff --git a/crates/ra_editor/src/code_actions.rs b/crates/ra_editor/src/code_actions.rs
index b0f0d8f1d0..216d592ff4 100644
--- a/crates/ra_editor/src/code_actions.rs
+++ b/crates/ra_editor/src/code_actions.rs
@@ -1,12 +1,11 @@
 use join_to_string::join;
 
 use ra_syntax::{
-    File, TextUnit, TextRange,
+    File, TextUnit, TextRange, Direction,
     ast::{self, AstNode, AttrsOwner, TypeParamsOwner, NameOwner},
     SyntaxKind::{COMMA, WHITESPACE},
     SyntaxNodeRef,
     algo::{
-        Direction, siblings,
         find_leaf_at_offset,
         find_covering_node,
     },
@@ -24,12 +23,12 @@ pub fn flip_comma<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce()
     let syntax = file.syntax();
 
     let comma = find_leaf_at_offset(syntax, offset).find(|leaf| leaf.kind() == COMMA)?;
-    let left = non_trivia_sibling(comma, Direction::Backward)?;
-    let right = non_trivia_sibling(comma, Direction::Forward)?;
+    let prev = non_trivia_sibling(comma, Direction::Prev)?;
+    let next = non_trivia_sibling(comma, Direction::Next)?;
     Some(move || {
         let mut edit = EditBuilder::new();
-        edit.replace(left.range(), right.text().to_string());
-        edit.replace(right.range(), left.text().to_string());
+        edit.replace(prev.range(), next.text().to_string());
+        edit.replace(next.range(), prev.text().to_string());
         LocalEdit {
             edit: edit.finish(),
             cursor_position: None,
@@ -129,7 +128,7 @@ pub fn introduce_variable<'a>(file: &'a File, range: TextRange) -> Option<impl F
 }
 
 fn non_trivia_sibling(node: SyntaxNodeRef, direction: Direction) -> Option<SyntaxNodeRef> {
-    siblings(node, direction)
+    node.siblings(direction)
         .skip(1)
         .find(|node| !node.kind().is_trivia())
 }
diff --git a/crates/ra_editor/src/extend_selection.rs b/crates/ra_editor/src/extend_selection.rs
index 2f8a04b2b3..b00a457b90 100644
--- a/crates/ra_editor/src/extend_selection.rs
+++ b/crates/ra_editor/src/extend_selection.rs
@@ -1,7 +1,7 @@
 use ra_syntax::{
-    File, TextRange, SyntaxNodeRef, TextUnit,
+    File, TextRange, SyntaxNodeRef, TextUnit, Direction,
     SyntaxKind::*,
-    algo::{find_leaf_at_offset, LeafAtOffset, find_covering_node, Direction, siblings},
+    algo::{find_leaf_at_offset, LeafAtOffset, find_covering_node},
 };
 
 pub fn extend_selection(file: &File, range: TextRange) -> Option<TextRange> {
@@ -71,12 +71,12 @@ fn pick_best<'a>(l: SyntaxNodeRef<'a>, r: SyntaxNodeRef<'a>) -> SyntaxNodeRef<'a
 }
 
 fn extend_comments(node: SyntaxNodeRef) -> Option<TextRange> {
-    let left = adj_comments(node, Direction::Backward);
-    let right = adj_comments(node, Direction::Forward);
-    if left != right {
+    let prev = adj_comments(node, Direction::Prev);
+    let next = adj_comments(node, Direction::Next);
+    if prev != next {
         Some(TextRange::from_to(
-            left.range().start(),
-            right.range().end(),
+            prev.range().start(),
+            next.range().end(),
         ))
     } else {
         None
@@ -85,7 +85,7 @@ fn extend_comments(node: SyntaxNodeRef) -> Option<TextRange> {
 
 fn adj_comments(node: SyntaxNodeRef, dir: Direction) -> SyntaxNodeRef {
     let mut res = node;
-    for node in siblings(node, dir) {
+    for node in node.siblings(dir) {
         match node.kind() {
             COMMENT => res = node,
             WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
diff --git a/crates/ra_editor/src/folding_ranges.rs b/crates/ra_editor/src/folding_ranges.rs
index 892aaf97be..733512368e 100644
--- a/crates/ra_editor/src/folding_ranges.rs
+++ b/crates/ra_editor/src/folding_ranges.rs
@@ -3,7 +3,7 @@ use std::collections::HashSet;
 use ra_syntax::{
     File, TextRange, SyntaxNodeRef,
     SyntaxKind,
-    algo::{Direction, siblings},
+    Direction,
 };
 
 #[derive(Debug, PartialEq, Eq)]
@@ -62,7 +62,7 @@ fn contiguous_range_for<'a>(
 
     let left = node;
     let mut right = node;
-    for node in siblings(node, Direction::Forward) {
+    for node in node.siblings(Direction::Next) {
         visited.insert(node);
         match node.kind() {
             SyntaxKind::WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
diff --git a/crates/ra_syntax/src/algo/mod.rs b/crates/ra_syntax/src/algo/mod.rs
index 3716a6000f..a6678093d9 100644
--- a/crates/ra_syntax/src/algo/mod.rs
+++ b/crates/ra_syntax/src/algo/mod.rs
@@ -94,22 +94,6 @@ pub fn find_covering_node(root: SyntaxNodeRef, range: TextRange) -> SyntaxNodeRe
     common_ancestor(left, right)
 }
 
-#[derive(Debug)]
-pub enum Direction {
-    Forward,
-    Backward,
-}
-
-pub fn siblings<'a>(
-    node: SyntaxNodeRef<'a>,
-    direction: Direction
-) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
-    generate(Some(node), move |&node| match direction {
-        Direction::Forward => node.next_sibling(),
-        Direction::Backward => node.prev_sibling(),
-    })
-}
-
 fn common_ancestor<'a>(n1: SyntaxNodeRef<'a>, n2: SyntaxNodeRef<'a>) -> SyntaxNodeRef<'a> {
     for p in n1.ancestors() {
         if n2.ancestors().any(|a| a == p) {
diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index c7eda45636..738664afd0 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -51,7 +51,7 @@ pub use {
     ast::AstNode,
     lexer::{tokenize, Token},
     syntax_kinds::SyntaxKind,
-    yellow::{SyntaxNode, SyntaxNodeRef, OwnedRoot, RefRoot, TreeRoot, SyntaxError},
+    yellow::{SyntaxNode, SyntaxNodeRef, OwnedRoot, RefRoot, TreeRoot, SyntaxError, Direction},
     reparsing::AtomEdit,
 };
 
diff --git a/crates/ra_syntax/src/yellow/mod.rs b/crates/ra_syntax/src/yellow/mod.rs
index 95d277a2fc..710320f47c 100644
--- a/crates/ra_syntax/src/yellow/mod.rs
+++ b/crates/ra_syntax/src/yellow/mod.rs
@@ -58,6 +58,13 @@ impl SyntaxNode {
         SyntaxNode(::rowan::SyntaxNode::new(green, errors))
     }
 }
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Direction {
+    Next,
+    Prev,
+}
+
 impl<'a> SyntaxNodeRef<'a> {
     pub fn leaf_text(self) -> Option<&'a SmolStr> {
         self.0.leaf_text()
@@ -71,6 +78,12 @@ impl<'a> SyntaxNodeRef<'a> {
             ::algo::walk::WalkEvent::Exit(_) => None,
         })
     }
+    pub fn siblings(self, direction: Direction) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
+        ::algo::generate(Some(self), move |&node| match direction {
+            Direction::Next => node.next_sibling(),
+            Direction::Prev => node.prev_sibling(),
+        })
+    }
 }
 
 impl<R: TreeRoot<RaTypes>> SyntaxNode<R> {