diff --git a/tools/codegen/src/com/android/codegen/FileInfo.kt b/tools/codegen/src/com/android/codegen/FileInfo.kt
index a1d0389b004170f1dd894e6bc7a492a7f6970ec0..cc3a156549568c3fb6130d7a0222a837a4934529 100644
--- a/tools/codegen/src/com/android/codegen/FileInfo.kt
+++ b/tools/codegen/src/com/android/codegen/FileInfo.kt
@@ -238,7 +238,7 @@ class FileInfo(
                     } else if (classBounds.isDataclass) {
 
                         // Insert placeholder for generated code to be inserted for the 1st time
-                        chunks.last = (chunks.last as Code)
+                        chunks[chunks.lastIndex] = (chunks.last() as Code)
                                 .lines
                                 .dropLastWhile { it.isBlank() }
                                 .run {
@@ -286,4 +286,4 @@ class FileInfo(
                     .let { addAll(it) }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/tools/codegen/src/com/android/codegen/Utils.kt b/tools/codegen/src/com/android/codegen/Utils.kt
index 9ceb2042d74e39e8fcf7191ae1bcc3c12e48f4c0..a40bdd7ba8e10a927d968ea39a49b7185029f8c0 100644
--- a/tools/codegen/src/com/android/codegen/Utils.kt
+++ b/tools/codegen/src/com/android/codegen/Utils.kt
@@ -137,14 +137,4 @@ private fun parseFailed(source: String, cause: Throwable? = null, desc: String =
             cause)
 }
 
-var <T> MutableList<T>.last
-    get() = last()
-    set(value) {
-        if (isEmpty()) {
-            add(value)
-        } else {
-            this[size - 1] = value
-        }
-    }
-
-inline fun <T> buildList(init: MutableList<T>.() -> Unit) = mutableListOf<T>().apply(init)
\ No newline at end of file
+inline fun <T> buildList(init: MutableList<T>.() -> Unit) = mutableListOf<T>().apply(init)