Use 'Any?' instead of throwing NPE when calculating star projection type

It's a quite hacky solution, but the choice seems to be conservative, so these types can be refined later

 #KT-9597 Fixed

compiler/testData/diagnostics/tests/generics/starProjections/invalid.kt

@@ -0,0 +1,26 @@
+// !CHECK_TYPE
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+// FILE: main.kt
+class Inv<T>(val x: T)
+
+class A<T : Inv<in T>> {
+    fun foo(): T = null!!
+}
+
+class Inv2<<!FINITE_BOUNDS_VIOLATION!>T : Inv2<in T><!>>(val x: T)
+
+fun main(a: A<*>, j: JavaClass<*>, i2: Inv2<*>) {
+    // Probably it's too restrictive to suppose star projection type here as Any?,
+    // but looks like we can refine it later
+    a.foo() checkType { _<Any?>() }
+    j.foo() checkType { _<Any?>() }
+    i2.x checkType { _<Any?>() }
+
+    j.<!MEMBER_PROJECTED_OUT!>bar<!>(1, 2, Any())
+}
+
+// FILE: JavaClass.java
+public class JavaClass<T extends JavaClass<? super T>> {
+    public void bar(T... x) {}
+    public T foo() {}
+}

compiler/testData/diagnostics/tests/generics/starProjections/invalid.txt

@@ -0,0 +1,36 @@
+package
+
+public fun main(/*0*/ a: A<*>, /*1*/ j: JavaClass<*>, /*2*/ i2: Inv2<*>): kotlin.Unit
+
+public final class A</*0*/ T : Inv<in T>> {
+    public constructor A</*0*/ T : Inv<in T>>()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): T
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Inv</*0*/ T> {
+    public constructor Inv</*0*/ T>(/*0*/ x: T)
+    public final val x: T
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Inv2</*0*/ T : Inv2<in T>> {
+    public constructor Inv2</*0*/ T : Inv2<in T>>(/*0*/ x: T)
+    public final val x: T
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open class JavaClass</*0*/ T : JavaClass<in T!>!> {
+    public constructor JavaClass</*0*/ T : JavaClass<in T!>!>()
+    public open fun bar(/*0*/ vararg x: T! /*kotlin.Array<(out) T!>!*/): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun foo(): T!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -8104,6 +8104,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/generics/starProjections/inheritedFromKotlin.kt");
                     doTest(fileName);
                 }
+
+                @TestMetadata("invalid.kt")
+                public void testInvalid() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/generics/starProjections/invalid.kt");
+                    doTest(fileName);
+                }
             }
 
             @TestMetadata("compiler/testData/diagnostics/tests/generics/tpAsReified")

core/descriptors/src/org/jetbrains/kotlin/types/StarProjectionImpl.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.types
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
 
 class StarProjectionImpl(
         private val typeParameter: TypeParameterDescriptor
@@ -45,7 +46,7 @@ fun TypeParameterDescriptor.starProjectionType(): KotlinType {
                         else null
 
             }
-    ).substitute(this.upperBounds.first(), Variance.OUT_VARIANCE)!!
+    ).substitute(this.upperBounds.first(), Variance.OUT_VARIANCE) ?: builtIns.defaultBound
 }
 
 class TypeBasedStarProjectionImpl(
@@ -56,4 +57,4 @@ class TypeBasedStarProjectionImpl(
     override fun getProjectionKind() = Variance.OUT_VARIANCE
 
     override fun getType() = _type
-}
+}