Support mapping between Java and Kotlin reflection objects

compiler/testData/codegen/boxAgainstJava/reflection/mapping/jClass2kClass.java

@@ -0,0 +1 @@
+public class jClass2kClass {}

compiler/testData/codegen/boxAgainstJava/reflection/mapping/jClass2kClass.kt

@@ -0,0 +1,11 @@
+import jClass2kClass as J
+
+import kotlin.reflect.jvm.*
+import kotlin.test.assertEquals
+
+fun box(): String {
+    val j = javaClass<J>()
+    assertEquals(j, j.kotlin.java)
+
+    return "OK"
+}

compiler/testData/codegen/boxAgainstJava/reflection/mapping/javaFields.java

@@ -0,0 +1,9 @@
+public class javaFields {
+    public final int i;
+    public String s;
+
+    public javaFields(int i, String s) {
+        this.i = i;
+        this.s = s;
+    }
+}

compiler/testData/codegen/boxAgainstJava/reflection/mapping/javaFields.kt

@@ -0,0 +1,43 @@
+import javaFields as J
+
+import java.lang.reflect.*
+import kotlin.reflect.*
+import kotlin.reflect.jvm.*
+
+fun box(): String {
+    val i = J::i
+    val s = J::s
+
+    // Check that correct reflection objects are created
+    assert(i.javaClass.getSimpleName() == "KForeignMemberProperty", "Fail i class")
+    assert(s.javaClass.getSimpleName() == "KMutableForeignMemberProperty", "Fail s class")
+
+    // Check that no Method objects are created for such properties
+    assert(i.javaGetter == null, "Fail i getter")
+    assert(s.javaGetter == null, "Fail s getter")
+    assert(s.javaSetter == null, "Fail s setter")
+
+    // Check that correct Field objects are created
+    val ji = i.javaField!!
+    val js = s.javaField!!
+    assert(Modifier.isFinal(ji.getModifiers()), "Fail i final")
+    assert(!Modifier.isFinal(js.getModifiers()), "Fail s final")
+
+    // Check that those Field objects work as expected
+    val a = J(42, "abc")
+    assert(ji.get(a) == 42, "Fail ji get")
+    assert(js.get(a) == "abc", "Fail js get")
+    js.set(a, "def")
+    assert(js.get(a) == "def", "Fail js set")
+    assert(a.s == "def", "Fail js access")
+
+    // Check that valid Kotlin reflection objects are created by those Field objects
+    val ki = ji.kotlin as KMemberProperty<J, Int>
+    val ks = js.kotlin as KMutableMemberProperty<J, String>
+    assert(ki.get(a) == 42, "Fail ki get")
+    assert(ks.get(a) == "def", "Fail ks get")
+    ks.set(a, "ghi")
+    assert(ks.get(a) == "ghi", "Fail ks set")
+
+    return "OK"
+}