2 files changed, 30 insertions, 34 deletions

diff --git a/crates/ra_editor/src/lib.rs b/crates/ra_editor/src/lib.rs
index dcf8be5a7..a8c68e79e 100644
--- a/crates/ra_editor/src/lib.rs
+++ b/crates/ra_editor/src/lib.rs
@@ -24,6 +24,7 @@ use ra_syntax::{
     SyntaxKind::{self, *},
     SyntaxNodeRef, TextRange, TextUnit,
 };
+use itertools::Itertools;
 
 #[derive(Debug)]
 pub struct HighlightedRange {
@@ -126,10 +127,8 @@ fn check_unnecessary_braces_in_use_statement(file: &SourceFileNode) -> Vec<Diagn
     let mut diagnostics = Vec::new();
     for node in file.syntax().descendants() {
         if let Some(use_tree_list) = ast::UseTreeList::cast(node) {
-            if use_tree_list.use_trees().count() == 1 {
+            if let Some((single_use_tree,)) = use_tree_list.use_trees().collect_tuple() {
                 let range = use_tree_list.syntax().range();
-                // use_tree_list always has one child, so we use unwrap directly here.
-                let single_use_tree: ast::UseTree = use_tree_list.use_trees().next().unwrap();
                 let edit = text_edit_for_remove_unnecessary_braces_with_self_in_use_statement(
                     single_use_tree,
                 )
@@ -282,24 +281,31 @@ fn test_foo() {}
 
     #[test]
     fn test_check_unnecessary_braces_in_use_statement() {
-        let file = SourceFileNode::parse(
-            r#"
-use a;
-use {b};
-use a::{c};
-use a::{self};
-use a::{c, d::e};
-use a::{c, d::{e}};
-fn main() {}
-"#,
+        fn check_not_applicable(code: &str) {
+            let file = SourceFileNode::parse(code);
+            let diagnostics = check_unnecessary_braces_in_use_statement(&file);
+            assert!(diagnostics.is_empty());
+        }
+
+        fn check_apply(before: &str, after: &str) {
+            let file = SourceFileNode::parse(before);
+            let diagnostic = check_unnecessary_braces_in_use_statement(&file)
+                .pop()
+                .unwrap_or_else(|| panic!("no diagnostics for:\n{}\n", before));
+            let fix = diagnostic.fix.unwrap();
+            let actual = fix.edit.apply(&before);
+            assert_eq_text!(after, &actual);
+        }
+
+        check_not_applicable(
+            "
+            use a;
+            use a::{c, d::e};
+        ",
         );
-        let diagnostics = check_unnecessary_braces_in_use_statement(&file);
-        assert_eq_dbg(
-            r#"[Diagnostic { range: [12; 15), msg: "Unnecessary braces in use statement", severity: WeakWarning, fix: Some(LocalEdit { label: "Remove unnecessary braces", edit: TextEdit { atoms: [AtomTextEdit { delete: [12; 12), insert: "b" }, AtomTextEdit { delete: [12; 15), insert: "" }] }, cursor_position: None }) },
-            Diagnostic { range: [24; 27), msg: "Unnecessary braces in use statement", severity: WeakWarning, fix: Some(LocalEdit { label: "Remove unnecessary braces", edit: TextEdit { atoms: [AtomTextEdit { delete: [24; 24), insert: "c" }, AtomTextEdit { delete: [24; 27), insert: "" }] }, cursor_position: None }) },
-            Diagnostic { range: [36; 42), msg: "Unnecessary braces in use statement", severity: WeakWarning, fix: Some(LocalEdit { label: "Remove unnecessary braces", edit: TextEdit { atoms: [AtomTextEdit { delete: [34; 42), insert: "" }] }, cursor_position: None }) },
-            Diagnostic { range: [76; 79), msg: "Unnecessary braces in use statement", severity: WeakWarning, fix: Some(LocalEdit { label: "Remove unnecessary braces", edit: TextEdit { atoms: [AtomTextEdit { delete: [76; 76), insert: "e" }, AtomTextEdit { delete: [76; 79), insert: "" }] }, cursor_position: None }) }]"#,
-            &diagnostics,
-        )
+        check_apply("use {b};", "use b;");
+        check_apply("use a::{c};", "use a::c;");
+        check_apply("use a::{self};", "use a;");
+        check_apply("use a::{c, d::{e}};", "use a::{c, d::e};");
     }
 }
diff --git a/crates/ra_editor/src/typing.rs b/crates/ra_editor/src/typing.rs
index f0d8dc7bb..21d068a7b 100644
--- a/crates/ra_editor/src/typing.rs
+++ b/crates/ra_editor/src/typing.rs
@@ -8,9 +8,8 @@ use ra_syntax::{
     SyntaxKind::*,
     SyntaxNodeRef, TextRange, TextUnit,
 };
-use ra_text_edit::text_utils::{
-    contains_offset_nonstrict
-};
+use ra_text_edit::text_utils::contains_offset_nonstrict;
+use itertools::Itertools;
 
 use crate::{find_node_at_offset, TextEditBuilder, LocalEdit};
 
@@ -246,7 +245,7 @@ fn single_expr(block: ast::Block) -> Option<ast::Expr> {
 
 fn join_single_use_tree(edit: &mut TextEditBuilder, node: SyntaxNodeRef) -> Option<()> {
     let use_tree_list = ast::UseTreeList::cast(node.parent()?)?;
-    let tree = single_use_tree(use_tree_list)?;
+    let (tree,) = use_tree_list.use_trees().collect_tuple()?;
     edit.replace(
         use_tree_list.syntax().range(),
         tree.syntax().text().to_string(),
@@ -254,15 +253,6 @@ fn join_single_use_tree(edit: &mut TextEditBuilder, node: SyntaxNodeRef) -> Opti
     Some(())
 }
 
-fn single_use_tree(tree_list: ast::UseTreeList) -> Option<ast::UseTree> {
-    let sub_use_trees = tree_list.use_trees().count();
-    if sub_use_trees != 1 {
-        return None;
-    }
-
-    tree_list.use_trees().next()
-}
-
 fn compute_ws(left: SyntaxNodeRef, right: SyntaxNodeRef) -> &'static str {
     match left.kind() {
         L_PAREN | L_BRACK => return "",