DescriptorRenderedImpl: fix order of val & vararg modifier for actual class

#KT-31921 Fixed

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt

@@ -821,14 +821,13 @@ internal class DescriptorRendererImpl(
         renderModifier(builder, valueParameter.isCrossinline, "crossinline")
         renderModifier(builder, valueParameter.isNoinline, "noinline")
 
-        if (renderPrimaryConstructorParametersAsProperties &&
-            (valueParameter.containingDeclaration as? ClassConstructorDescriptor)?.isPrimary == true
-        ) {
+        val isPrimaryConstructor = renderPrimaryConstructorParametersAsProperties &&
+                (valueParameter.containingDeclaration as? ClassConstructorDescriptor)?.isPrimary == true
+        if (isPrimaryConstructor) {
             renderModifier(builder, actualPropertiesInPrimaryConstructor, "actual")
-            renderModifier(builder, true, "val")
         }
 
-        renderVariable(valueParameter, includeName, builder, topLevel)
+        renderVariable(valueParameter, includeName, builder, topLevel, isPrimaryConstructor)
 
         val withDefaultValue =
             defaultParameterValueRenderer != null &&
@@ -838,21 +837,27 @@ internal class DescriptorRendererImpl(
         }
     }
 
-    private fun renderValVarPrefix(variable: VariableDescriptor, builder: StringBuilder) {
-        if (variable !is ValueParameterDescriptor) {
+    private fun renderValVarPrefix(variable: VariableDescriptor, builder: StringBuilder, isInPrimaryConstructor: Boolean = false) {
+        if (isInPrimaryConstructor || variable !is ValueParameterDescriptor) {
             builder.append(renderKeyword(if (variable.isVar) "var" else "val")).append(" ")
         }
     }
 
-    private fun renderVariable(variable: VariableDescriptor, includeName: Boolean, builder: StringBuilder, topLevel: Boolean) {
+    private fun renderVariable(
+        variable: VariableDescriptor,
+        includeName: Boolean,
+        builder: StringBuilder,
+        topLevel: Boolean,
+        isInPrimaryConstructor: Boolean = false
+    ) {
         val realType = variable.type
 
         val varargElementType = (variable as? ValueParameterDescriptor)?.varargElementType
         val typeToRender = varargElementType ?: realType
-
         renderModifier(builder, varargElementType != null, "vararg")
-        if (topLevel && !startFromName) {
-            renderValVarPrefix(variable, builder)
+
+        if (isInPrimaryConstructor || topLevel && !startFromName) {
+            renderValVarPrefix(variable, builder, isInPrimaryConstructor)
         }
 
         if (includeName) {

idea/testData/multiModuleQuickFix/expectClassWithVararg/header/My.kt

@@ -0,0 +1,2 @@
+// My: to be implemented
+// DISABLE-ERRORS

idea/testData/multiModuleQuickFix/expectClassWithVararg/header/My.kt.after

@@ -0,0 +1,3 @@
+// My: to be implemented
+// DISABLE-ERRORS
+expect annotation class My(vararg val arg: String) 

idea/testData/multiModuleQuickFix/expectClassWithVararg/jvm/My.kt

@@ -0,0 +1,4 @@
+// "Create expected annotation class in common module testModule_Common" "true"
+// DISABLE-ERRORS
+
+actual annotation class <caret>My actual constructor(actual vararg val arg: String)

idea/testData/multiModuleQuickFix/expectClassWithVararg/jvm/My.kt.after

@@ -0,0 +1,4 @@
+// "Create expected annotation class in common module testModule_Common" "true"
+// DISABLE-ERRORS
+
+actual annotation class My actual constructor(actual vararg val arg: String)

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixMultiModuleTestGenerated.java

@@ -364,6 +364,11 @@ public class QuickFixMultiModuleTestGenerated extends AbstractQuickFixMultiModul
         runTest("idea/testData/multiModuleQuickFix/expectClassWithSupertype/");
     }
 
+    @TestMetadata("expectClassWithVararg")
+    public void testExpectClassWithVararg() throws Exception {
+        runTest("idea/testData/multiModuleQuickFix/expectClassWithVararg/");
+    }
+
     @TestMetadata("expectCompanion")
     public void testExpectCompanion() throws Exception {
         runTest("idea/testData/multiModuleQuickFix/expectCompanion/");