3 files changed, 25 insertions, 4 deletions

diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index 6f005a2d8..95bf9db14 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -13,11 +13,21 @@ use crate::{
         make::{self, tokens},
         AstNode, TypeBoundsOwner,
     },
-    AstToken, Direction, InsertPosition, SmolStr, SyntaxElement,
+    AstToken, Direction, InsertPosition, SmolStr, SyntaxElement, SyntaxKind,
     SyntaxKind::{ATTR, COMMENT, WHITESPACE},
     SyntaxNode, SyntaxToken, T,
 };
 
+impl ast::BinExpr {
+    #[must_use]
+    pub fn replace_op(&self, op: SyntaxKind) -> Option<ast::BinExpr> {
+        let op_node: SyntaxElement = self.op_details()?.0.into();
+        let to_insert: Option<SyntaxElement> = Some(tokens::op(op).into());
+        let replace_range = RangeInclusive::new(op_node.clone(), op_node);
+        Some(replace_children(self, replace_range, to_insert.into_iter()))
+    }
+}
+
 impl ast::FnDef {
     #[must_use]
     pub fn with_body(&self, body: ast::Block) -> ast::FnDef {
diff --git a/crates/ra_syntax/src/ast/expr_extensions.rs b/crates/ra_syntax/src/ast/expr_extensions.rs
index 7c53aa934..2fd039837 100644
--- a/crates/ra_syntax/src/ast/expr_extensions.rs
+++ b/crates/ra_syntax/src/ast/expr_extensions.rs
@@ -127,7 +127,7 @@ pub enum BinOp {
 }
 
 impl ast::BinExpr {
-    fn op_details(&self) -> Option<(SyntaxToken, BinOp)> {
+    pub fn op_details(&self) -> Option<(SyntaxToken, BinOp)> {
         self.syntax().children_with_tokens().filter_map(|it| it.into_token()).find_map(|c| {
             let bin_op = match c.kind() {
                 T![||] => BinOp::BooleanOr,
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index 9749327fa..40db570da 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -173,10 +173,21 @@ fn ast_from_text<N: AstNode>(text: &str) -> N {
 }
 
 pub mod tokens {
-    use crate::{AstNode, Parse, SourceFile, SyntaxKind::*, SyntaxToken, T};
+    use crate::{AstNode, Parse, SourceFile, SyntaxKind, SyntaxKind::*, SyntaxToken, T};
     use once_cell::sync::Lazy;
 
-    static SOURCE_FILE: Lazy<Parse<SourceFile>> = Lazy::new(|| SourceFile::parse(",\n; ;"));
+    static SOURCE_FILE: Lazy<Parse<SourceFile>> =
+        Lazy::new(|| SourceFile::parse("const C: () = (1 != 1, 2 == 2)\n;"));
+
+    pub fn op(op: SyntaxKind) -> SyntaxToken {
+        SOURCE_FILE
+            .tree()
+            .syntax()
+            .descendants_with_tokens()
+            .filter_map(|it| it.into_token())
+            .find(|it| it.kind() == op)
+            .unwrap()
+    }
 
     pub fn comma() -> SyntaxToken {
         SOURCE_FILE