[GROOVY-8660] Unexpected MethodSelectionException with implicit null argument

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.0-alpha-2, 2.4.15, 2.5.0, 4.0.13
• Labels: varargs
• Assignee: Unassigned
• Reporter: Daniil Ovchinnikov
• Created: 22/Jun/18 12:33
• Updated: 22/Aug/23 15:30

Description

class OnlySingle {
    def foo(a) { "single param: $a" }
}

println new OnlySingle().foo()
// as expected: 'single param: null'


class OnlyVararg {
    def foo(a, ... b) { "vararg param: $a, $b" }
}

println new OnlyVararg().foo()
// as expected: 'MME: No signature of method: OnlyVararg.foo() is applicable for argument types: () values: []'

class Both {
    def foo(a) { "single param: $a" }
    def foo(a, ... b) { "vararg param: $a, $b" }
}

println new Both().foo()
// unexpected:
// MethodSelectionException: Could not find which method foo() to invoke from this list:
//  public java.lang.Object Both#foo(java.lang.Object)
//  public transient java.lang.Object Both#foo(java.lang.Object, [Ljava.lang.Object;)

If the exception is expected then OnlyVararg case should work too.
If the exception is unexpected then Both#foo(Object) should be selected.