From 070c64f9b5cdc559ab5287626d812eb3ed187cef Mon Sep 17 00:00:00 2001
From: Roman Artemev <roman.artemev@jetbrains.com>
Date: Mon, 27 Sep 2021 21:57:43 +0300
Subject: [PATCH] [JS IR] Add descriptive error message for `js("...")` call

Report a message instead of NPE if `js("...")`` code couldn't be emitted
---
 .../transformers/irToJs/IrElementToJsExpressionTransformer.kt | 4 +++-
 .../transformers/irToJs/IrElementToJsStatementTransformer.kt  | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt
index cc51d37902c..2499b536dfc 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt
@@ -192,7 +192,9 @@ class IrElementToJsExpressionTransformer : BaseIrElementToJsNodeTransformer<JsEx
 
     override fun visitCall(expression: IrCall, context: JsGenerationContext): JsExpression {
         if (context.checkIfJsCode(expression.symbol)) {
-            val statements = translateJsCodeIntoStatementList(expression.getValueArgument(0) ?: error("JsCode is expected"))!!
+            val statements = translateJsCodeIntoStatementList(expression.getValueArgument(0) ?: error("JsCode is expected"))
+                ?: error("Cannot compute js code for ${expression.render()}")
+
             if (statements.isEmpty()) return JsPrefixOperation(JsUnaryOperator.VOID, JsIntLiteral(3)) // TODO: report warning or even error
 
             val lastStatement = statements.last()
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt
index d3619167f41..127cdeac65d 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt
@@ -133,7 +133,8 @@ class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsSta
 
     override fun visitCall(expression: IrCall, data: JsGenerationContext): JsStatement {
         if (data.checkIfJsCode(expression.symbol)) {
-            val statements = translateJsCodeIntoStatementList(expression.getValueArgument(0) ?: error("JsCode is expected"))!!
+            val statements = translateJsCodeIntoStatementList(expression.getValueArgument(0) ?: error("JsCode is expected"))
+                ?: error("Cannot compute js code for ${expression.render()}")
             return when (statements.size) {
                 0 -> JsEmpty
                 1 -> statements.single().withSource(expression, data)