JVM_IR: generate file class without members if it has metadata

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/FileClassLowering.kt

@@ -59,7 +59,7 @@ private class FileClassLowering(val context: JvmBackendContext) : FileLoweringPa
                 fileClassMembers.add(it)
         }
 
-        if (fileClassMembers.isEmpty()) return
+        if (fileClassMembers.isEmpty() && irFile.metadata?.descriptors.isNullOrEmpty()) return
 
         val irFileClass = createFileClass(irFile, fileClassMembers)
         classes.add(irFileClass)

compiler/testData/ir/irText/declarations/fileWithTypeAliasesOnly.kt

@@ -0,0 +1 @@
+typealias Bar<T> = (T) -> String

compiler/testData/ir/irText/declarations/fileWithTypeAliasesOnly.txt

@@ -0,0 +1 @@
+FILE fqName:<root> fileName:/fileWithTypeAliasesOnly.kt

compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java

@@ -264,6 +264,11 @@ public class IrTextTestCaseGenerated extends AbstractIrTextTestCase {
             runTest("compiler/testData/ir/irText/declarations/fileWithAnnotations.kt");
         }
 
+        @TestMetadata("fileWithTypeAliasesOnly.kt")
+        public void testFileWithTypeAliasesOnly() throws Exception {
+            runTest("compiler/testData/ir/irText/declarations/fileWithTypeAliasesOnly.kt");
+        }
+
         @TestMetadata("interfaceProperties.kt")
         public void testInterfaceProperties() throws Exception {
             runTest("compiler/testData/ir/irText/declarations/interfaceProperties.kt");