This happened due to Groovy's dynamic compilation with Kotlin 1.3's type inference algorithm. ref: gradle/gradle#22529

We can take the following actions.

• Use static typed JVM language
• Use CompileStatic annotation in Groovy

---

As for Kotlin DSL, A build function that take an Action interface may fail depending on Gradle versions if it's originally written in Groovy.

groovySample { // Not a lambda of Action
  definitions { // Not a lambda of Action
    param = "${file("calling built-in function causes a weired behaviour!")}"

    anyLambda { // Action!
      "hello~"
    }
  }
}

Show cases

The following code does not cause any issue.

groovySample {
  definitions {
    anyLambda {
      "hello~"
    }
  }
}

The following code produces an error. We could sometimes see similar error messages with old Kotlin like 1.2 or lower if receivers of the lambda are ambiguous.

groovySample {
  definitions {
    anyLambda {
      "hello~"
    }
  }
}

// =>
* What went wrong:
Build_gradle$2$1$3
> Build_gradle$2$1$3

This behaviour depends on Gradle -- Groovy transitively.

Language	Gradle Version	Result
Java	6.6-6.8	Success
Groovy	6.6-6.7.1	Fail
Groovy	6.8-	Success

We cannot avoid this behaviour even if we specify the distribution Groovy version.

Conclusion

• Gradle version at runtime would cause this issue.
• Gradle plugins written in Groovy may not be reliable in some cases.
• A workaround is to use Java code for classes that provide Action interface.