ComparatorCompat strange behaviour, possible bug about lightweight-stream-api

[aNNiMON]

@wjtxyz I'm getting an ambiguous call in the second and third cases.

After calling ComparatorCompat.comparingInt(...) you get ComparatorCompat<T> instance, which implements java.util.Comparator<T> as well. Now, since you're using Java 8+, then default methods appear in java.util.Comparator interface. When you calling ComparatorCompat.comparingInt(...).thenComparingInt(...) there are two method candidates:

• ComparatorCompat<T> thenComparingInt(com.annimon.stream.function.ToIntFunction)
• default Comparator<T> thenComparingInt(java.util.function.ToIntFunction)

Both lambdas in the second and third cases can be java.util.function.ToIntFunction or com.annimon.stream.function.ToIntFunction.

• thenComparingInt(s -> Math.abs(s.getY()))
• thenComparingInt((TestClass s) -> Math.abs(s.getY()))

You need to help the compiler by specifying the type of the lambda.

import com.annimon.stream.function.ToIntFunction;

// Cast lambda to specific interface 
ComparatorCompat
        .comparingInt(TestClass::getX)
        .thenComparingInt((ToIntFunction<TestClass>)s -> Math.abs(s.getY()))
// Pass lambda as variable
ToIntFunction<TestClass> absY = s -> Math.abs(s.getY());
ComparatorCompat
        .comparingInt(TestClass::getX)
        .thenComparingInt(absY);