Support introspection of parameter names and indices in reflection

core/builtins/src/kotlin/reflect/KCallable.kt

@@ -31,4 +31,9 @@ public interface KCallable<out R> {
      *   the setter, similarly, will have the name "<set-foo>".
      */
     public val name: String
+
+    /**
+     * Parameters required to make a call to this callable.
+     */
+    public val parameters: List<KParameter>
 }

core/builtins/src/kotlin/reflect/KParameter.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.reflect
+
+/**
+ * Represents a parameter passed to a function or a property getter/setter,
+ * including `this` and extension receiver parameters.
+ */
+public interface KParameter {
+    /**
+     * 0-based index of this parameter in the parameter list of its containing callable.
+     */
+    public val index: Int
+
+    /**
+     * Name of this parameter as it was declared in the source code,
+     * or `null` if the parameter has no name or its name is not available at runtime.
+     * Examples of nameless parameters include `this` instance for member functions,
+     * extension receiver for extension functions or properties, parameters of Java methods
+     * compiled without the debug information, and others.
+     */
+    public val name: String?
+}