diff --git a/common-util/src/main/kotlin/com/google/devtools/ksp/common/impl/KSNameImpl.kt b/common-util/src/main/kotlin/com/google/devtools/ksp/common/impl/KSNameImpl.kt
index 0cbccba79d..c3475aa2a9 100644
--- a/common-util/src/main/kotlin/com/google/devtools/ksp/common/impl/KSNameImpl.kt
+++ b/common-util/src/main/kotlin/com/google/devtools/ksp/common/impl/KSNameImpl.kt
@@ -13,10 +13,12 @@ class KSNameImpl private constructor(val name: String) : KSName {
     }
 
     override fun getQualifier(): String {
-        return name.split(".").dropLast(1).joinToString(".")
+        val lastIndex = name.lastIndexOf('.')
+        return if (lastIndex != -1) name.substring(0, lastIndex) else ""
     }
 
     override fun getShortName(): String {
-        return name.split(".").last()
+        val lastIndex = name.lastIndexOf('.')
+        return if (lastIndex != -1) name.substring(lastIndex + 1) else name
     }
 }