Change Signature: Parenthesize functional type of receiver in the signature preview

#KT-8737 Fixed

compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt

@@ -88,13 +88,18 @@ public class KtPsiFactory(private val project: Project) {
     }
 
     public fun createType(type: String): KtTypeReference {
-        val typeReference = createProperty("val x : $type").typeReference
+        val typeReference = createTypeIfPossible(type)
         if (typeReference == null || typeReference.text != type) {
             throw IllegalArgumentException("Incorrect type: $type")
         }
         return typeReference
     }
 
+    public fun createTypeIfPossible(type: String): KtTypeReference? {
+        val typeReference = createProperty("val x : $type").typeReference
+        return if (typeReference?.text == type) typeReference else null
+    }
+
     public fun createStar(): PsiElement {
         return createType("List<*>").findElementAt(5)!!
     }

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/KotlinChangeInfo.kt

@@ -247,7 +247,13 @@ public open class KotlinChangeInfo(
 
             if (kind == Kind.FUNCTION) {
                 receiverParameterInfo?.let {
-                    buffer.append(it.currentTypeText).append('.')
+                    // TODO: Temporary solution until Change Signature is able to infer actual KotlinType from code fragments instead of using text representation
+                    if (KtPsiFactory(context).createTypeIfPossible(it.currentTypeText)?.typeElement is KtFunctionType) {
+                        buffer.append("(${it.currentTypeText})")
+                    } else {
+                        buffer.append(it.currentTypeText)
+                    }
+                    buffer.append('.')
                 }
             }