diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsCode.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsCode.kt
index 04db72e31ed..129e975999a 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsCode.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsCode.kt
@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.ir.expressions.IrCall
 import org.jetbrains.kotlin.ir.expressions.IrConst
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrStringConcatenation
+import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
@@ -24,7 +25,7 @@ fun translateJsCode(call: IrCall, scope: JsScope): JsNode {
     fun foldString(expression: IrExpression): String {
         val builder = StringBuilder()
         expression.acceptVoid(object : IrElementVisitorVoid {
-            override fun visitElement(element: IrElement) = error("Parameter of js function must be compile time String constant")
+            override fun visitElement(element: IrElement) = error("Parameter of js function must be compile time String constant, not ${element.render()}")
 
             override fun <T> visitConst(expression: IrConst<T>) {
                 builder.append(expression.kind.valueOf(expression))