Support Void.TYPE as underlying Class object for KClass

#KT-20875 Fixed

compiler/testData/codegen/box/classLiteral/java/javaPrimitiveType.kt

@@ -50,14 +50,15 @@ fun box(): String {
     check(Double::class.javaPrimitiveType, "double")
     check(Double::class, "double")
 
+    check(Void::class.javaPrimitiveType, "void")
+    check(Void::class, "void")
+
     checkNull(String::class.javaPrimitiveType)
     checkNull(String::class)
 
-    checkNull(Nothing::class.javaPrimitiveType)
+    // TODO: KT-15518
-    checkNull(Nothing::class)
+    check(Nothing::class.javaPrimitiveType, "void")
-
+    check(Nothing::class, "void")
-    checkNull(Void::class.javaPrimitiveType)
-    checkNull(Void::class)
 
     return "OK"
 }

compiler/testData/codegen/box/classLiteral/java/javaPrimitiveTypeReified.kt

@@ -26,9 +26,9 @@ fun box(): String {
     check<Float>("float")
     check<Long>("long")
     check<Double>("double")
+    check<Void>("void")
 
     checkNull<String>()
-    checkNull<Void>()
 
     return "OK"
 }

compiler/testData/codegen/box/reflection/classes/javaVoid.kt

@@ -0,0 +1,17 @@
+// IGNORE_BACKEND: JS, NATIVE
+// WITH_REFLECT
+
+import kotlin.reflect.KClass
+import kotlin.test.assertEquals
+
+fun box(): String {
+    assertEquals(Void::class, Void.TYPE.kotlin)
+    assertEquals(Void.TYPE.kotlin, Void::class)
+
+    assertEquals(Void.TYPE, Void::class.javaPrimitiveType)
+    assertEquals(Void::class.java, Void::class.javaObjectType)
+    assertEquals(Void.TYPE, Void.TYPE.kotlin.javaPrimitiveType)
+    assertEquals(Void::class.java, Void.TYPE.kotlin.javaObjectType)
+
+    return "OK"
+}

compiler/testData/codegen/box/reflection/noReflectAtRuntime/javaVoid.kt

@@ -0,0 +1,17 @@
+// IGNORE_BACKEND: JS, NATIVE
+// WITH_RUNTIME
+
+import kotlin.reflect.KClass
+import kotlin.test.assertEquals
+
+fun box(): String {
+    assertEquals(Void::class, Void.TYPE.kotlin)
+    assertEquals(Void.TYPE.kotlin, Void::class)
+
+    assertEquals(Void.TYPE, Void::class.javaPrimitiveType)
+    assertEquals(Void::class.java, Void::class.javaObjectType)
+    assertEquals(Void.TYPE, Void.TYPE.kotlin.javaPrimitiveType)
+    assertEquals(Void::class.java, Void.TYPE.kotlin.javaObjectType)
+
+    return "OK"
+}

compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -16249,6 +16249,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 doTest(fileName);
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/javaVoid.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("jvmName.kt")
             public void testJvmName() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/jvmName.kt");
@@ -17275,6 +17281,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 doTest(fileName);
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/javaVoid.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("primitiveJavaClass.kt")
             public void testPrimitiveJavaClass() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/primitiveJavaClass.kt");

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

@@ -16249,6 +16249,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/javaVoid.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("jvmName.kt")
             public void testJvmName() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/jvmName.kt");
@@ -17275,6 +17281,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/javaVoid.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("primitiveJavaClass.kt")
             public void testPrimitiveJavaClass() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/primitiveJavaClass.kt");

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

@@ -16249,6 +16249,12 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 doTest(fileName);
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/javaVoid.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("jvmName.kt")
             public void testJvmName() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/jvmName.kt");
@@ -17275,6 +17281,12 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 doTest(fileName);
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/javaVoid.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("primitiveJavaClass.kt")
             public void testPrimitiveJavaClass() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/primitiveJavaClass.kt");

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

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.load.java.descriptors.JavaPropertyDescriptor
 import org.jetbrains.kotlin.load.java.sources.JavaSourceElement
 import org.jetbrains.kotlin.load.kotlin.JvmPackagePartSource
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.NameUtils
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMap
 import org.jetbrains.kotlin.resolve.DescriptorUtils
@@ -156,6 +157,8 @@ private val Method.signature: String
             returnType.desc
 
 internal object RuntimeTypeMapper {
+    private val JAVA_LANG_VOID = ClassId.topLevel(FqName("java.lang.Void"))
+
     fun mapSignature(possiblySubstitutedFunction: FunctionDescriptor): JvmFunctionSignature {
         // Fake overrides don't have a source element, so we need to take a declaration.
         // TODO: support the case when a fake override overrides several declarations with different signatures
@@ -263,6 +266,8 @@ internal object RuntimeTypeMapper {
             return ClassId.topLevel(KotlinBuiltIns.FQ_NAMES.array.toSafe())
         }
 
+        if (klass == Void.TYPE) return JAVA_LANG_VOID
+
         klass.primitiveType?.let {
             return ClassId(KotlinBuiltIns.BUILT_INS_PACKAGE_FQ_NAME, it.typeName)
         }

core/runtime.jvm/src/kotlin/jvm/JvmClassMapping.kt

@@ -55,6 +55,7 @@ public val <T : Any> KClass<T>.javaPrimitiveType: Class<T>?
             "java.lang.Float"     -> Float::class.java
             "java.lang.Long"      -> Long::class.java
             "java.lang.Double"    -> Double::class.java
+            "java.lang.Void"      -> Void.TYPE
             else -> null
         } as Class<T>?
     }
@@ -77,6 +78,7 @@ public val <T : Any> KClass<T>.javaObjectType: Class<T>
             "float"   -> JavaLangFloat::class.java
             "long"    -> JavaLangLong::class.java
             "double"  -> JavaLangDouble::class.java
+            "void"    -> Void::class.java
             else -> thisJClass
         } as Class<T>
     }

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -18193,6 +18193,18 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/javaVoid.kt");
+                try {
+                    doTest(fileName);
+                }
+                catch (Throwable ignore) {
+                    return;
+                }
+                throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
+            }
+
             @TestMetadata("jvmName.kt")
             public void testJvmName() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/jvmName.kt");
@@ -20065,6 +20077,18 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
             }
 
+            @TestMetadata("javaVoid.kt")
+            public void testJavaVoid() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/javaVoid.kt");
+                try {
+                    doTest(fileName);
+                }
+                catch (Throwable ignore) {
+                    return;
+                }
+                throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
+            }
+
             @TestMetadata("primitiveJavaClass.kt")
             public void testPrimitiveJavaClass() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/noReflectAtRuntime/primitiveJavaClass.kt");