Convert parameter to receiver: don't remove 'override' and 'vararg' when function has 'vararg' parameter

#KT-28851 Fixed

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

@@ -33,6 +33,7 @@ import org.jetbrains.kotlin.psi.psiUtil.quoteIfNeeded
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.calls.components.isVararg
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 import org.jetbrains.kotlin.resolve.scopes.receivers.ImplicitReceiver
 import org.jetbrains.kotlin.types.isError
@@ -153,7 +154,9 @@ class KotlinParameterInfo @JvmOverloads constructor (
         val defaultRendering = currentTypeInfo.render()
         val typeSubstitutor = inheritedCallable.typeSubstitutor ?: return defaultRendering
         val currentBaseFunction = inheritedCallable.baseFunction.currentCallableDescriptor ?: return defaultRendering
-        val parameterType = currentBaseFunction.valueParameters[parameterIndex].type
+        val parameter = currentBaseFunction.valueParameters[parameterIndex]
+        if (parameter.isVararg) return defaultRendering
+        val parameterType = parameter.type
         if (parameterType.isError) return defaultRendering
         return parameterType.renderTypeWithSubstitution(typeSubstitutor, defaultRendering, true)
     }

idea/testData/intentions/convertParameterToReceiver/hasVararg.kt

@@ -0,0 +1,7 @@
+interface A {
+    fun foo(<caret>s: String, vararg args: Any)
+}
+class B : A {
+    override fun foo(s: String, vararg args: Any) {
+    }
+}

idea/testData/intentions/convertParameterToReceiver/hasVararg.kt.after

@@ -0,0 +1,7 @@
+interface A {
+    fun String.foo(vararg args: Any)
+}
+class B : A {
+    override fun String.foo(vararg args: Any) {
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -6051,6 +6051,11 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             runTest("idea/testData/intentions/convertParameterToReceiver/functionExpressionWithThisConflict.kt");
         }
 
+        @TestMetadata("hasVararg.kt")
+        public void testHasVararg() throws Exception {
+            runTest("idea/testData/intentions/convertParameterToReceiver/hasVararg.kt");
+        }
+
         @TestMetadata("lambdaParameter.kt")
         public void testLambdaParameter() throws Exception {
             runTest("idea/testData/intentions/convertParameterToReceiver/lambdaParameter.kt");