Reflection: add KClassifier.starProjectedType

#KT-8998 In Progress

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

@@ -0,0 +1,23 @@
+// WITH_REFLECT
+
+import kotlin.reflect.KTypeProjection
+import kotlin.reflect.createType
+import kotlin.reflect.starProjectedType
+import kotlin.test.assertEquals
+
+class Foo<K, V>
+
+fun box(): String {
+    val foo = Foo::class.starProjectedType
+    assertEquals(Foo::class, foo.classifier)
+    assertEquals(listOf(KTypeProjection.Star, KTypeProjection.Star), foo.arguments)
+    assertEquals(foo, Foo::class.createType(listOf(KTypeProjection.Star, KTypeProjection.Star)))
+
+    assertEquals(String::class, String::class.starProjectedType.classifier)
+    assertEquals(listOf(), String::class.starProjectedType.arguments)
+
+    val tp = Foo::class.typeParameters.first()
+    assertEquals(tp.createType(), tp.starProjectedType)
+
+    return "OK"
+}

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

@@ -11933,6 +11933,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/qualifiedName.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("starProjectedType.kt")
+            public void testStarProjectedType() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reflection/classes/starProjectedType.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("compiler/testData/codegen/box/reflection/constructors")

core/reflection.jvm/src/kotlin/reflect/KClassifiers.kt

@@ -19,10 +19,8 @@ package kotlin.reflect
 
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.types.*
-import kotlin.reflect.jvm.internal.KClassImpl
 import kotlin.reflect.jvm.internal.KClassifierImpl
 import kotlin.reflect.jvm.internal.KTypeImpl
-import kotlin.reflect.jvm.internal.KTypeParameterImpl
 
 /**
  * Creates a [KType] instance with the given classifier, type arguments, nullability and annotations.
@@ -76,3 +74,20 @@ private fun createKotlinType(
         }
     }, nullable)
 }
+
+/**
+ * Creates an instance of [KType] with the given classifier, substituting all its type parameters with star projections.
+ * The resulting type is not marked as nullable and does not have any annotations.
+ *
+ * @see [KClassifier.createType]
+ */
+val KClassifier.starProjectedType: KType
+    get() {
+        val descriptor = (this as? KClassifierImpl)?.descriptor
+                         ?: return createType()
+
+        val typeParameters = descriptor.typeConstructor.parameters
+        if (typeParameters.isEmpty()) return createType() // TODO: optimize, get defaultType from ClassDescriptor
+
+        return createType(typeParameters.map { KTypeProjection.Star })
+    }