[FIR] Implement SPREAD_OF_NULLABLE

compiler/testData/diagnostics/tests/varargs/NullableTypeForVarargArgument.fir.kt

@@ -29,9 +29,9 @@ fun baz(s: String) {}
 fun getArr(): Array<String>? = null
 
 fun f() {
-    A().foo(1, *args)
-    bar(2, *<!ARGUMENT_TYPE_MISMATCH!>args<!>)
-    baz(<!NON_VARARG_SPREAD!>*<!><!ARGUMENT_TYPE_MISMATCH!>args<!>)
+    A().foo(1, <!SPREAD_OF_NULLABLE!>*<!>args)
+    bar(2, <!SPREAD_OF_NULLABLE!>*<!><!ARGUMENT_TYPE_MISMATCH!>args<!>)
+    baz(<!NON_VARARG_SPREAD, SPREAD_OF_NULLABLE!>*<!><!ARGUMENT_TYPE_MISMATCH!>args<!>)
 }
 
 fun g(args: Array<String>?) {
@@ -48,18 +48,18 @@ class B {
 
 fun h(b: B) {
     if (b.args != null) {
-        A().foo(1, *b.args)
+        A().foo(1, <!SPREAD_OF_NULLABLE!>*<!>b.args)
     }
 }
 
 fun k() {
-    A().foo(1, *getArr())
-    bar(2, *<!ARGUMENT_TYPE_MISMATCH!>getArr()<!>)
-    baz(<!NON_VARARG_SPREAD!>*<!><!ARGUMENT_TYPE_MISMATCH!>getArr()<!>)
+    A().foo(1, <!SPREAD_OF_NULLABLE!>*<!>getArr())
+    bar(2, <!SPREAD_OF_NULLABLE!>*<!><!ARGUMENT_TYPE_MISMATCH!>getArr()<!>)
+    baz(<!NON_VARARG_SPREAD, SPREAD_OF_NULLABLE!>*<!><!ARGUMENT_TYPE_MISMATCH!>getArr()<!>)
 }
 
 fun invokeTest(goodArgs: Array<String>) {
     J.staticFun(*goodArgs)
-    J.staticFun(*args)
-    J.staticFun(*args <!USELESS_ELVIS_RIGHT_IS_NULL!>?: null<!>)
+    J.staticFun(<!SPREAD_OF_NULLABLE!>*<!>args)
+    J.staticFun(<!SPREAD_OF_NULLABLE!>*<!>args <!USELESS_ELVIS_RIGHT_IS_NULL!>?: null<!>)
 }

compiler/testData/diagnostics/tests/varargs/inferredNullableArrayAsVararg.fir.kt

@@ -1,15 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_PARAMETER
-
-// FILE: Test.java
-public class Test {
-    static public void foo(String ... x) {
-
-    }
-}
-
-// FILE: test.kt
-fun <T> select(vararg x: T) = x[1]
-
-fun main(x: Array<String>?) {
-    Test.foo(*(select(arrayOf(""), null))) // no compilation errors before the fix, NPE
-}

compiler/testData/diagnostics/tests/varargs/inferredNullableArrayAsVararg.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 // FILE: Test.java