[GROOVY-10086] STC misses type error when calling a vararg method

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-beta-1, 2.5.18, 3.0.12
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 13/May/21 09:25
• Updated: 18/Jul/22 16:49
• Resolved: 16/May/21 02:01

Description

I have the following program

 

class Foo {}

class X<T> {
  T f;
  X(T f) {
    this.f = f;
  }

  T getF() {
    this.f;
  }
}

class A {
  void foo(int x, X<Foo>... y) {
    Foo foo = y[0].getF(); // ClastCastException at runtime
  }
}

public class Main {
    public static void main(String[] args) {
      A a = new A();
      a.foo(1, new X<>(1));
    }
}

Actual Behaviour

groovyc compiles this program, but we get the following exception at runtime

Exception in thread "main" org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object '1' with class 'java.lang.Integer' to class 'Foo'
        at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.continueCastOnSAM(DefaultTypeTransformation.java:415)
        at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.continueCastOnNumber(DefaultTypeTransformation.java:329)
        at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.castToType(DefaultTypeTransformation.java:243)
        at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:318)
        at A.foo(test.groovy:16)
        at Main.main(test.groovy:23)

Expected Behaviour

groovyc should have rejected this program with an error similar to the following

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 23: [Static type checking] - Cannot call A#foo(int, X<Foo>[]) with arguments [int, X<java.lang.Integer>]
 @ line 23, column 7.
         a.foo(1, new X<>(1));
         ^1 error

Tested against master (https://github.com/apache/groovy/commit/2df019d3c93486e8a32d407d364913e7b65e1cba)