ADDITIONAL SYSTEM INFORMATION :
Windows 10

A DESCRIPTION OF THE PROBLEM :
A very specific combination of a lambda and a generic method confuses type inference, such that the compiler doesn't see the lambda parameter. Same compilation occurs on version 17-ea.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the source

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Successful compilation
ACTUAL -
example\Example.java:19: error: cannot find symbol
                return func2.apply(func1.apply(arg));
                                               ^
  symbol: variable arg
1 error


---------- BEGIN SOURCE ----------
package example;

import java.util.function.Function;
import java.util.function.IntFunction;

class Example {
    interface GenericOp<A> {
        <B> A apply(IntFunction<B> func1, Function<B, A> func2);
    }

    static <A> GenericOp<A> foo(IntFunction<GenericOp<A>> f) {
        throw new UnsupportedOperationException();
    }

    static <A> GenericOp<A> bar() {
        return foo((int arg) -> new GenericOp<>() {
            @Override
            public <B> A apply(IntFunction<B> func1, Function<B, A> func2) {
                return func2.apply(func1.apply(arg));
            }
        });
    }
}

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

CUSTOMER SUBMITTED WORKAROUND :
Adding an explicit type variable in the construction of the anonymous class gives the compiler enough information:

        return foo((int arg) -> new GenericOp<A>() {


FREQUENCY : always