diff --git a/uast/uast-common/src/com/intellij/patterns/uast/UastPatterns.kt b/uast/uast-common/src/com/intellij/patterns/uast/UastPatterns.kt
index 910fbf55dd78..2fb81d39c10e 100644
--- a/uast/uast-common/src/com/intellij/patterns/uast/UastPatterns.kt
+++ b/uast/uast-common/src/com/intellij/patterns/uast/UastPatterns.kt
@@ -77,7 +77,7 @@ private val constructorOrMethodCall = setOf(UastCallKind.CONSTRUCTOR_CALL, UastC
 private fun isCallExpressionParameter(argumentExpression: UExpression,
                                       parameterIndex: Int,
                                       callPattern: ElementPattern<UCallExpression>): Boolean {
-  val call = argumentExpression.uastParent.getUCallExpression(searchLimit = 2) as? UCallExpressionEx ?: return false
+  val call = argumentExpression.uastParent.getUCallExpression(searchLimit = 2) ?: return false
   if (call.kind !in constructorOrMethodCall) return false
   return call.getArgumentForParameter(parameterIndex) == unwrapPolyadic(argumentExpression) && callPattern.accepts(call)
 }
diff --git a/uast/uast-common/src/org/jetbrains/uast/UastUtils.kt b/uast/uast-common/src/org/jetbrains/uast/UastUtils.kt
index 56d579238365..f1415a26605e 100644
--- a/uast/uast-common/src/org/jetbrains/uast/UastUtils.kt
+++ b/uast/uast-common/src/org/jetbrains/uast/UastUtils.kt
@@ -206,29 +206,11 @@ fun UCallExpression.getParameterForArgument(arg: UExpression): PsiParameter? {
   val psiMethod = resolve() ?: return null
   val parameters = psiMethod.parameterList.parameters
 
-  if (this is UCallExpressionEx)
-    return parameters.withIndex().find { (i, p) ->
-      val argumentForParameter = getArgumentForParameter(i) ?: return@find false
-      if (argumentForParameter == arg) return@find true
-      if (arg is ULambdaExpression && arg.sourcePsi?.parent == argumentForParameter.sourcePsi) return@find true // workaround for KT-25297
-      if (p.isVarArgs && argumentForParameter is UExpressionList) return@find argumentForParameter.expressions.contains(arg)
-      return@find false
-    }?.value
-
-  // not everyone implements UCallExpressionEx, lets try to guess
-  val indexInArguments = valueArguments.indexOf(arg)
-  if (parameters.size == valueArguments.count()) {
-    return parameters.getOrNull(indexInArguments)
-  }
-  // probably it is a kotlin extension method
-  if (parameters.size - 1 == valueArguments.count()) {
-    val parameter = parameters.firstOrNull() ?: return null
-    val receiverType = receiverType ?: return null
-    if (!parameter.type.isAssignableFrom(receiverType)) return null
-    if (!parameters.drop(1).zip(valueArguments)
-        .all { (param, arg) -> arg.getExpressionType()?.let { param.type.isAssignableFrom(it) } == true }) return null
-    return parameters.getOrNull(indexInArguments + 1)
-  }
-  //named parameters are not processed
-  return null
+  return parameters.withIndex().find { (i, p) ->
+    val argumentForParameter = getArgumentForParameter(i) ?: return@find false
+    if (argumentForParameter == arg) return@find true
+    if (arg is ULambdaExpression && arg.sourcePsi?.parent == argumentForParameter.sourcePsi) return@find true // workaround for KT-25297
+    if (p.isVarArgs && argumentForParameter is UExpressionList) return@find argumentForParameter.expressions.contains(arg)
+    return@find false
+  }?.value
 }
diff --git a/uast/uast-tests/test/org/jetbrains/uast/test/java/JavaUastApiTest.kt b/uast/uast-tests/test/org/jetbrains/uast/test/java/JavaUastApiTest.kt
index a5a5784d4342..26a9b12c69b9 100644
--- a/uast/uast-tests/test/org/jetbrains/uast/test/java/JavaUastApiTest.kt
+++ b/uast/uast-tests/test/org/jetbrains/uast/test/java/JavaUastApiTest.kt
@@ -111,7 +111,6 @@ class JavaUastApiTest : AbstractJavaUastTest() {
     doTest("Simple/CallExpression.java") { _, file ->
       fun assertArguments(argumentsInPositionalOrder: List<String?>?, refText: String) =
         file.findElementByTextFromPsi<UCallExpression>(refText).let { call ->
-          if (call !is UCallExpressionEx) throw AssertionError("${call.javaClass} is not a UCallExpressionEx")
           Assert.assertEquals(
             argumentsInPositionalOrder, call.resolve()?.let { psiMethod ->
             (0 until psiMethod.parameterList.parametersCount).map {