Fix KCallable#callBy to JvmStatic companion object members

#KT-12915 Fixed

compiler/testData/codegen/box/reflection/callBy/companionObject.kt

@@ -0,0 +1,31 @@
+// WITH_REFLECT
+
+import kotlin.test.assertEquals
+
+class C {
+    companion object {
+        fun foo(a: String, b: String = "b") = a + b
+    }
+}
+
+fun box(): String {
+    val f = C.Companion::class.members.single { it.name == "foo" }
+
+    // Any object method currently requires the object instance passed
+    try {
+        f.callBy(mapOf(
+                f.parameters.single { it.name == "a" } to "a"
+        ))
+        return "Fail: IllegalArgumentException should have been thrown"
+    }
+    catch (e: IllegalArgumentException) {
+        // OK
+    }
+
+    assertEquals("ab", f.callBy(mapOf(
+            f.parameters.first() to C,
+            f.parameters.single { it.name == "a" } to "a"
+    )))
+
+    return "OK"
+}

compiler/testData/codegen/box/reflection/callBy/jvmStaticInCompanionObject.kt

@@ -0,0 +1,34 @@
+// WITH_REFLECT
+
+// KT-12915 IAE on callBy of JvmStatic function with default arguments
+
+import kotlin.test.assertEquals
+
+class C {
+    companion object {
+        @JvmStatic
+        fun foo(a: String, b: String = "b") = a + b
+    }
+}
+
+fun box(): String {
+    val f = C.Companion::class.members.single { it.name == "foo" }
+
+    // Any object method currently requires the object instance passed
+    try {
+        f.callBy(mapOf(
+                f.parameters.single { it.name == "a" } to "a"
+        ))
+        return "Fail: IllegalArgumentException should have been thrown"
+    }
+    catch (e: IllegalArgumentException) {
+        // OK
+    }
+
+    assertEquals("ab", f.callBy(mapOf(
+            f.parameters.first() to C,
+            f.parameters.single { it.name == "a" } to "a"
+    )))
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -11259,6 +11259,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/box/reflection/callBy"), Pattern.compile("^(.+)\\.kt$"), true);
             }
 
+            @TestMetadata("companionObject.kt")
+            public void testCompanionObject() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/callBy/companionObject.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("defaultAndNonDefaultIntertwined.kt")
             public void testDefaultAndNonDefaultIntertwined() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/callBy/defaultAndNonDefaultIntertwined.kt");
@@ -11271,6 +11277,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("jvmStaticInCompanionObject.kt")
+            public void testJvmStaticInCompanionObject() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/callBy/jvmStaticInCompanionObject.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("jvmStaticInObject.kt")
             public void testJvmStaticInObject() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/callBy/jvmStaticInObject.kt");

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KFunctionImpl.kt

@@ -16,6 +16,7 @@
 
 package kotlin.reflect.jvm.internal
 
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.Visibilities
 import java.lang.reflect.Constructor
@@ -89,7 +90,11 @@ internal open class KFunctionImpl protected constructor(
         when (member) {
             is Constructor<*> -> FunctionCaller.Constructor(member)
             is Method -> when {
-                descriptor.annotations.findAnnotation(JVM_STATIC) != null ->
+                // Note that static $default methods for @JvmStatic functions are generated differently in objects and companion objects.
+                // In objects, $default's signature does _not_ contain the additional object instance parameter,
+                // as opposed to companion objects where the first parameter is the companion object instance.
+                descriptor.annotations.findAnnotation(JVM_STATIC) != null &&
+                !(descriptor.containingDeclaration as ClassDescriptor).isCompanionObject ->
                     FunctionCaller.JvmStaticInObject(member)
 
                 else -> FunctionCaller.StaticMethod(member)