KT-9721:

- Kotlin/JS still uses package facades.
Handle them properly in StubClassBuilder parentStack.
- Generate backend-related diagnostics in IDE
using light class generation for file facades.
- Drop PackageFacadeStubCache.

idea/src/META-INF/plugin.xml

@@ -246,9 +246,6 @@
 
     <projectService serviceImplementation="org.jetbrains.kotlin.idea.versions.SuppressNotificationState"/>
 
-    <projectService serviceInterface="org.jetbrains.kotlin.asJava.KotlinLightClassForFacade$PackageFacadeStubCache"
-                    serviceImplementation="org.jetbrains.kotlin.asJava.KotlinLightClassForFacade$PackageFacadeStubCache"/>
-
     <projectService serviceInterface="org.jetbrains.kotlin.asJava.KotlinLightClassForFacade$FacadeStubCache"
                     serviceImplementation="org.jetbrains.kotlin.asJava.KotlinLightClassForFacade$FacadeStubCache"/>
 

idea/testData/checker/duplicateJvmSignature/functionAndProperty/topLevelMultifileRuntime.kt

@@ -0,0 +1,13 @@
+@file:JvmName("TopLevelMultifile")
+@file:JvmMultifileClass
+package test
+
+import kotlin.jvm.JvmName
+import kotlin.jvm.JvmMultifileClass
+
+<error descr="[CONFLICTING_JVM_DECLARATIONS] Platform declaration clash: The following declarations have the same JVM signature (getX()I):
+    fun <get-x>(): kotlin.Int
+    fun getX(): kotlin.Int">val x</error> = 1
+<error descr="[CONFLICTING_JVM_DECLARATIONS] Platform declaration clash: The following declarations have the same JVM signature (getX()I):
+    fun <get-x>(): kotlin.Int
+    fun getX(): kotlin.Int">fun getX()</error> = 1

idea/tests/org/jetbrains/kotlin/checkers/JetPsiCheckerTestGenerated.java

@@ -630,6 +630,12 @@ public class JetPsiCheckerTestGenerated extends AbstractJetPsiCheckerTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("topLevelMultifileRuntime.kt")
+            public void testTopLevelMultifileRuntime() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/checker/duplicateJvmSignature/functionAndProperty/topLevelMultifileRuntime.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("trait.kt")
             public void testTrait() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/checker/duplicateJvmSignature/functionAndProperty/trait.kt");