2 files changed, 11 insertions, 5 deletions

diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index f74c9f9c6..bdaecdc43 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -251,7 +251,7 @@ impl ast::UseItem {
     #[must_use]
     pub fn with_use_tree(&self, use_tree: ast::UseTree) -> ast::UseItem {
         if let Some(old) = self.use_tree() {
-            return self.replace_descendants(iter::once((old, use_tree)));
+            return self.replace_descendant(old, use_tree);
         }
         self.clone()
     }
@@ -283,7 +283,7 @@ impl ast::UseTree {
     #[must_use]
     pub fn with_path(&self, path: ast::Path) -> ast::UseTree {
         if let Some(old) = self.path() {
-            return self.replace_descendants(iter::once((old, path)));
+            return self.replace_descendant(old, path);
         }
         self.clone()
     }
@@ -291,7 +291,7 @@ impl ast::UseTree {
     #[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 self.replace_descendants(iter::once((old, use_tree_list)));
+            return self.replace_descendant(old, use_tree_list);
         }
         self.clone()
     }
@@ -466,6 +466,11 @@ pub trait AstNodeEdit: AstNode + Sized {
     }
 
     #[must_use]
+    fn replace_descendant<D: AstNode>(&self, old: D, new: D) -> Self {
+        self.replace_descendants(iter::once((old, new)))
+    }
+
+    #[must_use]
     fn replace_descendants<D: AstNode>(
         &self,
         replacement_map: impl IntoIterator<Item = (D, D)>,
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index 69bacf224..4621c9888 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -127,7 +127,7 @@ pub fn condition(expr: ast::Expr, pattern: Option<ast::Pat>) -> ast::Condition {
     match pattern {
         None => ast_from_text(&format!("const _: () = while {} {{}};", expr)),
         Some(pattern) => {
-            ast_from_text(&format!("const _: () = while {} = {} {{}};", pattern, expr))
+            ast_from_text(&format!("const _: () = while let {} = {} {{}};", pattern, expr))
         }
     }
 }
@@ -245,7 +245,8 @@ pub fn let_stmt(pattern: ast::Pat, initializer: Option<ast::Expr>) -> ast::LetSt
     ast_from_text(&format!("fn f() {{ {} }}", text))
 }
 pub fn expr_stmt(expr: ast::Expr) -> ast::ExprStmt {
-    ast_from_text(&format!("fn f() {{ {}; }}", expr))
+    let semi = if expr.is_block_like() { "" } else { ";" };
+    ast_from_text(&format!("fn f() {{ {}{} (); }}", expr, semi))
 }
 
 pub fn token(kind: SyntaxKind) -> SyntaxToken {