diff --git a/kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/ProguardRules.kt b/kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/ProguardRules.kt
index b819f44..d7bbdba 100644
--- a/kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/ProguardRules.kt
+++ b/kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/ProguardRules.kt
@@ -49,27 +49,27 @@ internal data class ProguardConfig(
     val targetName = targetClass.reflectionName()
     val adapterCanonicalName = ClassName(targetClass.packageName, adapterName).canonicalName
     // Keep the class name for Moshi's reflective lookup based on it
-    appendln("-if class $targetName")
-    appendln("-keepnames class $targetName")
+    appendLine("-if class $targetName")
+    appendLine("-keepnames class $targetName")
 
-    appendln("-if class $targetName")
-    appendln("-keep class $adapterCanonicalName {")
+    appendLine("-if class $targetName")
+    appendLine("-keep class $adapterCanonicalName {")
     // Keep the constructor for Moshi's reflective lookup
     val constructorArgs = adapterConstructorParams.joinToString(",")
-    appendln("    public <init>($constructorArgs);")
+    appendLine("    public <init>($constructorArgs);")
     // Keep any qualifier properties
     for (qualifierProperty in qualifierProperties) {
-      appendln("    private com.squareup.moshi.JsonAdapter ${qualifierProperty.name};")
+      appendLine("    private com.squareup.moshi.JsonAdapter ${qualifierProperty.name};")
     }
-    appendln("}")
+    appendLine("}")
 
     qualifierProperties.asSequence()
       .flatMap { it.qualifiers.asSequence() }
       .map(ClassName::reflectionName)
       .sorted()
       .forEach { qualifier ->
-        appendln("-if class $targetName")
-        appendln("-keep @interface $qualifier")
+        appendLine("-if class $targetName")
+        appendLine("-keep @interface $qualifier")
       }
 
     if (targetConstructorHasDefaults) {
@@ -80,10 +80,10 @@ internal data class ProguardConfig(
       //     synthetic <init>(...);
       // }
       //
-      appendln("-if class $targetName")
-      appendln("-keepnames class kotlin.jvm.internal.DefaultConstructorMarker")
-      appendln("-if class $targetName")
-      appendln("-keepclassmembers class $targetName {")
+      appendLine("-if class $targetName")
+      appendLine("-keepnames class kotlin.jvm.internal.DefaultConstructorMarker")
+      appendLine("-if class $targetName")
+      appendLine("-keepclassmembers class $targetName {")
       val allParams = targetConstructorParams.toMutableList()
       val maskCount = if (targetConstructorParams.isEmpty()) {
         0
@@ -95,8 +95,8 @@ internal data class ProguardConfig(
       }
       allParams += "kotlin.jvm.internal.DefaultConstructorMarker"
       val params = allParams.joinToString(",")
-      appendln("    public synthetic <init>($params);")
-      appendln("}")
+      appendLine("    public synthetic <init>($params);")
+      appendLine("}")
     }
   }
 }