Invocations of signature polymorphic methods (MethodHandle.invoke, MethodHandle.invokeExact) derive the bytecode descriptor of the method call from the call site rather than the method's declared signature ("([Ljava/lang/Object;)Ljava/lang/Object;"). See JLS 15.12.3.

A method handle like MethodHandle::invoke or mh::invoke should do the same. But currently, the descriptor generated by javac always seems to be "([Ljava/lang/Object;)Ljava/lang/Object;".

Test case:

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import java.lang.invoke.*;

public class MHInvoke {

  interface TriFunction {
      Object apply(String a, char b, char c) throws Throwable;
  }

  public static void main(String... args) throws Throwable {
      MethodHandles.Lookup lookup = MethodHandles.lookup();
      MethodType mt = MethodType.methodType(String.class, char.class, char.class);
      MethodHandle ms = lookup.findVirtual(String.class, "replace", mt);

      System.out.println("result 1: " + ms.invoke("some string to search", 's', 'o'));
      
      TriFunction f1 = (a, b, c) -> ms.invoke(a,b,c);
      System.out.println("result 2: " + f1.apply("some string to search", 's', 'o'));
      
      TriFunction f2 = ms::invoke;
      System.out.println("result 3: " + f2.apply("some string to search", 's', 'o'));
  }
}

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Expected: Run successfully
Actual: BootstrapMethodError

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Looking at the bytecode, here's the 'invoke' call from the lambda body:

         4: invokevirtual #15 // Method java/lang/invoke/MethodHandle.invoke:(Ljava/lang/String;CC)Ljava/lang/Object;

And here's the 'invoke' call for the method reference (passed as an argument to 'metafactory' in the form of a MethodHandle):

        #74 invokevirtual java/lang/invoke/MethodHandle.invoke:([Ljava/lang/Object;)Ljava/lang/Object;

This should look like the following instead:

        #74 invokevirtual java/lang/invoke/MethodHandle.invoke:(Ljava/lang/String;CC)Ljava/lang/Object;