Add passing test case for Issue 6636 (#6637)

framework/tests/all-systems/java21/Issue6636.java

@@ -0,0 +1,27 @@
+// @below-java21-jdk-skip-test
+
+// None of the WPI formats supports the new Java 21 languages features, so skip inference until they
+// do.
+// @infer-jaifs-skip-test
+// @infer-ajava-skip-test
+// @infer-stubs-skip-test
+
+import java.util.function.Function;
+
+public class Issue6636 {
+  interface Decorator {
+    <In, Out> Function<In, Out> decorate(Function<? super In, ? extends Out> target);
+  }
+
+  interface Targets {
+    <In, Out> Function<In, Out> get(Class<In> in, Class<Out> out);
+  }
+
+  record Request() {}
+
+  record Response() {}
+
+  public Response call(Decorator decorator, Targets targets, Request request) {
+    return decorator.decorate(targets.get(Request.class, Response.class)).apply(request);
+  }
+}