Validate arguments of KTypeProjection constructor

#KT-34596 Fixed

libraries/stdlib/src/kotlin/reflect/KType.kt

@@ -73,6 +73,16 @@ public data class KTypeProjection constructor(
      */
     public val type: KType?
 ) {
+
+    init {
+        require((variance == null) == (type == null)) {
+            if (variance == null)
+                "Star projection must have no type specified."
+            else
+                "The projection variance $variance requires type to be specified."
+        }
+    }
+
     override fun toString(): String = when (variance) {
         null -> "*"
         KVariance.INVARIANT -> type.toString()

libraries/stdlib/test/reflection/KTypeProjectionTest.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package test.reflection
+
+import kotlin.reflect.KTypeProjection
+import kotlin.reflect.KVariance
+import kotlin.reflect.typeOf
+import kotlin.test.*
+
+class KTypeProjectionTest {
+    @Test
+    fun constructorArgumentsValidation() {
+        assertFailsWith<IllegalArgumentException> { KTypeProjection(null, typeOf<Int>()) }
+        for (variance in KVariance.values()) {
+            assertFailsWith<IllegalArgumentException> { KTypeProjection(variance, null) }.let { e ->
+                assertTrue(variance.toString() in e.message!!)
+            }
+        }
+    }
+}