Compiler error - java.lang.IllegalArgumentException when compiling some method references code

When compiling the following code:

----------------------------------------
import java.lang.reflect.Method;

public class BridgeMethod {
    interface K<T> {void m(T t);}
    interface M {void m(String s);}
    interface KM extends K<String>, M{} //generic substitution
    
    private static void assertTrue(boolean cond) {
        if (!cond)
            throw new AssertionError();
    }

    static void bar(String s) {
        System.out.println("BridgeMethod.bar(String) " + s);
    }

    public static void main(String[] args) {
        KM km = BridgeMethod#bar(String); //<<<<<<<<<<<<<<<<<error occurs here
        ...
----------------------------------------

The following compiler error was encountered:
----------System.err:(13/756)----------
java.lang.IllegalArgumentException: not a single-method interface: BridgeMethod$KM
at java.lang.invoke.MethodHandleProxies.asInterfaceInstance(MethodHandleProxies.java:140)
at BridgeMethod.main(BridgeMethod.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.sun.javatest.regtest.MainAction$SameVMRunnable.run(MainAction.java:680)
at java.lang.Thread.run(Thread.java:722)

Where KM IS a SAM interface.