diff --git a/lib/kotlin/build.gradle.kts b/lib/kotlin/build.gradle.kts
index cd52e7f..754df89 100644
--- a/lib/kotlin/build.gradle.kts
+++ b/lib/kotlin/build.gradle.kts
@@ -40,7 +40,7 @@
     }
 }
 
-tasks.withType<KotlinCompile> {
+tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
     kotlinOptions.jvmTarget = "1.8"
 }
 
@@ -57,7 +57,7 @@
 
     task<Exec>("compileThrift") {
         val thriftBin = if (hasProperty("thrift.compiler")) {
-            file(property("thrift.compiler"))
+            file(property("thrift.compiler")!!)
         } else {
             project.rootDir.resolve("../../compiler/cpp/thrift")
         }