Take into account vararg modifier in "Add type" quick fix

So #KT-20894 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/AddTypeAnnotationToValueParameterFix.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.core.ShortenReferences
 import org.jetbrains.kotlin.idea.project.builtIns
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
+import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtCollectionLiteralExpression
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtParameter
@@ -40,11 +41,16 @@ class AddTypeAnnotationToValueParameterFix(element: KtParameter) : KotlinQuickFi
     init {
         val defaultValue = element.defaultValue
         var type = defaultValue?.getType(defaultValue.analyze(BodyResolveMode.PARTIAL))
-        if (defaultValue is KtCollectionLiteralExpression && type != null && KotlinBuiltIns.isArray(type)) {
-            val builtIns = element.builtIns
-            val elementType = builtIns.getArrayElementType(type)
-            if (KotlinBuiltIns.isPrimitiveType(elementType)) {
-                type = builtIns.getPrimitiveArrayKotlinTypeByPrimitiveKotlinType(elementType)
+        if (type != null && KotlinBuiltIns.isArray(type)) {
+            if (element.hasModifier(KtTokens.VARARG_KEYWORD)) {
+                type = type.arguments.singleOrNull()?.type
+            }
+            else if (defaultValue is KtCollectionLiteralExpression) {
+                val builtIns = element.builtIns
+                val elementType = builtIns.getArrayElementType(type)
+                if (KotlinBuiltIns.isPrimitiveType(elementType)) {
+                    type = builtIns.getPrimitiveArrayKotlinTypeByPrimitiveKotlinType(elementType)
+                }
             }
         }
 

idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralDouble.kt

@@ -0,0 +1,4 @@
+// "Add type 'Double' to parameter 'value'" "true"
+// LANGUAGE_VERSION: 1.2
+
+annotation class CollectionDefault(vararg val value = [1.0, 2.2]<caret>)

idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralDouble.kt.after

@@ -0,0 +1,4 @@
+// "Add type 'Double' to parameter 'value'" "true"
+// LANGUAGE_VERSION: 1.2
+
+annotation class CollectionDefault(vararg val value: Double = [1.0, 2.2])

idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralInt.kt

@@ -0,0 +1,4 @@
+// "Add type 'Int' to parameter 'value'" "true"
+// LANGUAGE_VERSION: 1.2
+
+annotation class CollectionDefault(vararg val value = [1, 2]<caret>)

idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralInt.kt.after

@@ -0,0 +1,4 @@
+// "Add type 'Int' to parameter 'value'" "true"
+// LANGUAGE_VERSION: 1.2
+
+annotation class CollectionDefault(vararg val value: Int = [1, 2])

idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralString.kt

@@ -0,0 +1,4 @@
+// "Add type 'String' to parameter 'value'" "true"
+// LANGUAGE_VERSION: 1.2
+
+annotation class CollectionDefault(vararg val value = ["alpha", "beta"]<caret>)

idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralString.kt.after

@@ -0,0 +1,4 @@
+// "Add type 'String' to parameter 'value'" "true"
+// LANGUAGE_VERSION: 1.2
+
+annotation class CollectionDefault(vararg val value: String = ["alpha", "beta"])

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

@@ -1025,6 +1025,24 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("annotationWithVarargArrayLiteralDouble.kt")
+        public void testAnnotationWithVarargArrayLiteralDouble() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralDouble.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("annotationWithVarargArrayLiteralInt.kt")
+        public void testAnnotationWithVarargArrayLiteralInt() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralInt.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("annotationWithVarargArrayLiteralString.kt")
+        public void testAnnotationWithVarargArrayLiteralString() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addTypeAnnotationToValueParameter/annotationWithVarargArrayLiteralString.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("noDefaultValue.kt")
         public void testNoDefaultValue() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addTypeAnnotationToValueParameter/noDefaultValue.kt");