2 files changed, 47 insertions, 13 deletions

diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index 1858e2b6c..40a04b9c5 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -139,7 +139,7 @@ impl ast::RecordFieldList {
         let mut to_insert: ArrayVec<[SyntaxElement; 4]> = ArrayVec::new();
         to_insert.push(space.into());
         to_insert.push(field.syntax().clone().into());
-        to_insert.push(tokens::comma().into());
+        to_insert.push(make::token(T![,]).into());
 
         macro_rules! after_l_curly {
             () => {{
@@ -160,7 +160,7 @@ impl ast::RecordFieldList {
                 {
                     InsertPosition::After(comma)
                 } else {
-                    to_insert.insert(0, tokens::comma().into());
+                    to_insert.insert(0, make::token(T![,]).into());
                     InsertPosition::After($anchor.syntax().clone().into())
                 }
             };
@@ -259,6 +259,24 @@ impl ast::UseItem {
     }
 }
 
+impl ast::UseTree {
+    #[must_use]
+    pub fn with_path(&self, path: ast::Path) -> ast::UseTree {
+        if let Some(old) = self.path() {
+            return replace_descendants(self, iter::once((old, path)));
+        }
+        self.clone()
+    }
+
+    #[must_use]
+    pub fn with_use_tree_list(&self, use_tree_list: ast::UseTreeList) -> ast::UseTree {
+        if let Some(old) = self.use_tree_list() {
+            return replace_descendants(self, iter::once((old, use_tree_list)));
+        }
+        self.clone()
+    }
+}
+
 #[must_use]
 pub fn strip_attrs_and_docs<N: ast::AttrsOwner>(node: &N) -> N {
     N::cast(strip_attrs_and_docs_inner(node.syntax().clone())).unwrap()
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index 0da24560e..53d6fa562 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -25,6 +25,31 @@ fn path_from_text(text: &str) -> ast::Path {
     ast_from_text(text)
 }
 
+pub fn use_tree(
+    path: ast::Path,
+    use_tree_list: Option<ast::UseTreeList>,
+    alias: Option<ast::Alias>,
+) -> ast::UseTree {
+    let mut buf = "use ".to_string();
+    buf += &path.syntax().to_string();
+    if let Some(use_tree_list) = use_tree_list {
+        buf += &format!("::{}", use_tree_list.syntax());
+    }
+    if let Some(alias) = alias {
+        buf += &format!(" {}", alias.syntax());
+    }
+    ast_from_text(&buf)
+}
+
+pub fn use_tree_list(use_trees: impl IntoIterator<Item = ast::UseTree>) -> ast::UseTreeList {
+    let use_trees = use_trees.into_iter().map(|it| it.syntax().clone()).join(", ");
+    ast_from_text(&format!("use {{{}}};", use_trees))
+}
+
+pub fn use_item(use_tree: ast::UseTree) -> ast::UseItem {
+    ast_from_text(&format!("use {};", use_tree.syntax()))
+}
+
 pub fn record_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::RecordField {
     return match expr {
         Some(expr) => from_text(&format!("{}: {}", name.syntax(), expr.syntax())),
@@ -219,22 +244,13 @@ fn unroot(n: SyntaxNode) -> SyntaxNode {
 }
 
 pub mod tokens {
-    use crate::{ast, AstNode, Parse, SourceFile, SyntaxKind::*, SyntaxToken, T};
     use once_cell::sync::Lazy;
 
+    use crate::{ast, AstNode, Parse, SourceFile, SyntaxKind::*, SyntaxToken};
+
     pub(super) static SOURCE_FILE: Lazy<Parse<SourceFile>> =
         Lazy::new(|| SourceFile::parse("const C: <()>::Item = (1 != 1, 2 == 2, !true)\n;"));
 
-    pub fn comma() -> SyntaxToken {
-        SOURCE_FILE
-            .tree()
-            .syntax()
-            .descendants_with_tokens()
-            .filter_map(|it| it.into_token())
-            .find(|it| it.kind() == T![,])
-            .unwrap()
-    }
-
     pub fn single_space() -> SyntaxToken {
         SOURCE_FILE
             .tree()