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 57f7d86..bde3eaa 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
@@ -47,7 +47,7 @@ internal data class ProguardConfig(
     // }
     //
     val targetName = targetClass.canonicalName
-    val adapterCanonicalName = ClassName(targetClass.packageName, adapterName)
+    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")