Packages: move Ranges, Progression, ProgressionIterators to kotlin.ranges and PrimitiveIterators to kotlin.collections.

js/js.frontend/src/org/jetbrains/kotlin/js/descriptorUtils/descriptorUtils.kt

@@ -18,21 +18,21 @@ package org.jetbrains.kotlin.js.descriptorUtils
 
 import com.intellij.openapi.util.text.StringUtil
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
 import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.utils.addToStdlib.check
 
 val KotlinType.nameIfStandardType: Name?
     get() {
-        val descriptor = constructor.declarationDescriptor
-
-        if (descriptor?.containingDeclaration == descriptor?.builtIns?.builtInsPackageFragment) {
-            return descriptor?.name
-        }
-
-        return null
+        return constructor.declarationDescriptor
+                ?.check { descriptor ->
+                    descriptor.builtIns.isBuiltInPackageFragment(descriptor.containingDeclaration as? PackageFragmentDescriptor)
+                }
+                ?.name
     }
 
 fun KotlinType.getJetTypeFqName(printTypeArguments: Boolean): String {