ADDITIONAL SYSTEM INFORMATION :
Linux Mint 21.3, Adoptium 21.0.2

A DESCRIPTION OF THE PROBLEM :
When developing a custom library that utilizes Spring's WebClient, I encountered a weird issue with generics which involves a family of interfaces described in Spring's WebClient class. In short, source file would not compile if a method reference is used, but will compile just fine if that method reference was replaced with an identical lambda. To avoid complicating things, I've thrown together a minimal reproducible example which mimics the interface hierarchy of WebClient and illustrates the issue

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Compile the attached source code with a simple javac <path/to/file.java>
2. Observe that it compiles without issues
3. In the main method, comment out the line with a lambda and uncomment the line with a method reference
4. Compile the file again with a simple javac <path/to/file.java>

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Source file compiles without issues
ACTUAL -
The following error is reported:

<path/to/file.java>:24: error: method invoke in class ReproducibleExample cannot be applied to given types;
        invoke(Receiver::getRootWithExtra);
        ^
  required: Function<? super Receiver,? extends ES>
  found: Receiver::[...]Extra
  reason: inferred type does not conform to equality constraint(s)
    inferred: S#2
    equality constraints(s): CAP#1
  where ES,S#1,S#2 are type-variables:
    ES extends RootWithExtraInterface<S#1> declared in method <S#1,ES>invoke(Function<? super Receiver,? extends ES>)
    S#1 extends RootInterface<S#1> declared in method <S#1,ES>invoke(Function<? super Receiver,? extends ES>)
    S#2 extends RootInterface<S#2>
  where CAP#1 is a fresh type-variable:
    CAP#1 extends RootInterface<CAP#1> from capture of ?
1 error


---------- BEGIN SOURCE ----------
import java.util.function.Function;

public class ReproducibleExample {
    // Stand-in for WebClient
    private interface Receiver {
        // Stand-in for get() (or any other method with the same return type)
        RootWithExtraInterface<?> getRootWithExtra();
    }
    // Stand-in for RequestHeadersSpec
    private interface RootInterface<S extends RootInterface<S>> {}
    // Stand-in for UriSpec
    private interface ExtraInterface<S extends RootInterface<?>> {}
    // Stand-in for RequestHeadersUriSpec
    private interface RootWithExtraInterface<S extends RootInterface<S>> extends RootInterface<S>, ExtraInterface<S> {}

    private static <S extends RootInterface<S>, ES extends RootWithExtraInterface<S>> S invoke(
            Function<? super Receiver, ? extends ES> function
    ) {
        return null;
    }

    public static void main(String[] args) {
        invoke(receiver -> receiver.getRootWithExtra());
// invoke(Receiver::getRootWithExtra);
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Using lambda instead of a method reference and staring at a yellow wavy-line in your IDE which prompts you to convert it to a method reference.

FREQUENCY : always