[scripts] KTNB-1391, KTNB-819, KTIJ-37776 Choose KtBlockExpression as a container for top-level script declarations

We had all top-level refactoring-generated declarations inserted into KtScript element. However, the contract is that all declarations should be inserted into its child, KtBlockExpression.


Merge-request: IJ-MR-193891
Merged-by: Ilya Muradyan <Ilya.Muradyan@jetbrains.com>

(cherry picked from commit f4a388dc736bd8bb4396520124b27f34999aab8c)

IJ-MR-194486

GitOrigin-RevId: 53cf4675dcdd6401f53b8903b05d21218348c6ff

plugins/kotlin/refactorings/kotlin.refactorings.common/src/org/jetbrains/kotlin/idea/refactoring/kotlinCommonRefactoringUtil.kt

@@ -86,6 +86,7 @@ import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import org.jetbrains.kotlin.psi.psiUtil.quoteIfNeeded
 import org.jetbrains.kotlin.psi.psiUtil.siblings
 import org.jetbrains.kotlin.psi.unpackFunctionLiteral
+import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 import java.util.Collections
 import kotlin.math.min
 
@@ -412,7 +413,16 @@ fun PsiElement.getExtractionContainers(strict: Boolean = true, includeAll: Boole
 
     return when (enclosingDeclaration) {
         is KtFile -> Collections.singletonList(enclosingDeclaration)
-        is KtScript -> Collections.singletonList(enclosingDeclaration)
+        is KtScript -> {
+            /**
+             * [KtScript] element is essentially a class, so it should always have
+             * a single child, which is a [KtBlockExpression]. Inserting an element as an immediate child
+             * of the [KtScript] element is a mistake.
+             */
+            Collections.singletonList(
+                enclosingDeclaration.children.firstIsInstanceOrNull<KtBlockExpression>() ?: enclosingDeclaration
+            )
+        }
         is KtClassBody -> getAllExtractionContainers(strict).filterIsInstance<KtClassBody>()
         else -> {
             val targetContainer = when (enclosingDeclaration) {