[GROOVY-7836] CompileStatic + static inner class + EqualsAndHashCode gives VerifyError in equals

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.6
• Fix Version/s: 2.4.7
• Component/s: Static compilation
• Assignee: Unassigned
• Reporter: Jason Winnebeck
• Created: 10/May/16 19:48
• Updated: 02/Nov/16 00:15
• Resolved: 26/Aug/16 02:10

Description

import groovy.transform.CompileStatic
import groovy.transform.EqualsAndHashCode

@CompileStatic
class Parent {
    List<Integer> getInts() { [0] }

    @EqualsAndHashCode
    static class Child {
        List<Integer> ints
    }
}

println GroovySystem.version
println new Parent.Child()

The key is the inner class having a property matching the parent's.

Result:

2.4.6
java.lang.VerifyError: (class: Parent$Child, method: equals signature: (Ljava/lang/Object;)Z) Incompatible object argument for function call

Inspecting the bytecode, I see the following:

   L13
    ALOAD 0
    INVOKEVIRTUAL Parent.getInts ()Ljava/util/List;
    ALOAD 2
    INVOKEVIRTUAL Parent$Child.getInts ()Ljava/util/List;
    INVOKESTATIC org/codehaus/groovy/runtime/ScriptBytecodeAdapter.compareEqual (Ljava/lang/Object;Ljava/lang/Object;)Z
    IFNE L14
    ICONST_1

It appears that the bytecode is attempting to call a method on the outer class, even though the inner class is static and there is no reason to access the outer class.