From 7b0f03cc1c81f7d8d59bd9acc1cb946a6b06ecf2 Mon Sep 17 00:00:00 2001
From: Igor Chevdar <igor.chevdar@jetbrains.com>
Date: Thu, 24 Oct 2019 17:29:04 +0300
Subject: [PATCH] [IR] Made IR validator weaker during validating IrConstNull

---
 .../kotlin/backend/common/CheckIrElementVisitor.kt | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/CheckIrElementVisitor.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/CheckIrElementVisitor.kt
index 0611257bafb..0aec9fdf0a4 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/CheckIrElementVisitor.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/CheckIrElementVisitor.kt
@@ -25,7 +25,6 @@ import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.types.*
-import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.resolve.descriptorUtil.isEffectivelyExternal
@@ -59,6 +58,14 @@ class CheckIrElementVisitor(
         }
     }
 
+    private fun IrExpression.ensureNullable() {
+        if (!config.checkTypes)
+            return
+
+        if (!type.isNullable())
+            reportError(this, "expected a nullable type, got ${type.render()}")
+    }
+
     private fun IrExpression.ensureTypeIs(expectedType: IrType) {
         ensureTypesEqual(type, expectedType)
     }
@@ -73,7 +80,10 @@ class CheckIrElementVisitor(
         super.visitConst(expression)
 
         val naturalType = when (expression.kind) {
-            IrConstKind.Null -> irBuiltIns.nothingNType
+            IrConstKind.Null -> {
+                expression.ensureNullable()
+                return
+            }
             IrConstKind.Boolean -> irBuiltIns.booleanType
             IrConstKind.Char -> irBuiltIns.charType
             IrConstKind.Byte -> irBuiltIns.byteType