diff --git a/docs/internals/optimizer.rst b/docs/internals/optimizer.rst
index ccb72b939..19bca791e 100644
--- a/docs/internals/optimizer.rst
+++ b/docs/internals/optimizer.rst
@@ -529,13 +529,13 @@ The above would be transformed into
 .. code-block:: yul
 
     {
-        let _1 = 0x20
-        let _2 = 0x456
-        let _3 = mload(_2)
-        let _4 = mul(_3, _1)
-        let _5 = 0x123
-        let _6 = mload(_5)
-        let z = add(_6, _4)
+        let _1 := 0x20
+        let _2 := 0x456
+        let _3 := mload(_2)
+        let _4 := mul(_3, _1)
+        let _5 := 0x123
+        let _6 := mload(_5)
+        let z := add(_6, _4)
     }
 
 Note that this transformation does not change the order of opcodes or function calls.