Weird implicit cast hangs the compiler in pattern matching.

```haxe
class Test {
static function main() {
final v = new Vector([1, 2]);
switch v {
case [1,2]: true;
case _: false;
}
}
}

abstract Vector(Array) {
public inline function new(a)
this = a;
@:from static function fromVector(v:Vector):Vector
return cast v;
}
```

Compiler seems to be stuck in a loop. From https://github.com/haxetink/tink_pure/issues/18