Bug: []= operator with a sequence key (Java backend?)

[arseniiv]

Code:

void foo(m) {
    KeyedCorrespondenceMutator<[Integer, Float], Boolean> m;
    value intfloat = [0, 0.0];
    m[intfloat] = false; // m[[0, 0.0]] is okay
//  ^1^2
}

Errors:

1. Ceylon backend error: method invoked with incorrect number of arguments; expected 2, found 0
2. Ceylon backend error: incompatible types: ceylon.language.Sequence cannot be converted to capture#1 of ? super ceylon.language.Sequence<? extends java.lang.Object>

Web runner (and so, JS backend) seems okay with this: the code runs and, as expected, puts false at [0, 0.0] in case of HashMap, no errors.