From 9638af042d4138b889193d478e4bd3015e0cfd62 Mon Sep 17 00:00:00 2001
From: Ivan Kylchik <ivan.kylchik@jetbrains.com>
Date: Fri, 4 Jun 2021 13:22:51 +0300
Subject: [PATCH] Support proper behavior in interpreter for cast of null value

---
 .../kotlin/ir/interpreter/IrInterpreter.kt    | 28 ++++++++++++-------
 .../intrinsics/IntrinsicImplementations.kt    |  1 +
 .../exceptions/nullPointerException.kt        | 11 ++++++++
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/IrInterpreter.kt b/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/IrInterpreter.kt
index 02dd0f0d94d..1f30e8b0014 100644
--- a/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/IrInterpreter.kt
+++ b/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/IrInterpreter.kt
@@ -456,33 +456,41 @@ class IrInterpreter private constructor(
         val isErased = typeClassifier.owner is IrTypeParameter && !isReified
         val typeOperand = if (isReified) (callStack.getState(typeClassifier) as KTypeState).irType else expression.typeOperand
 
+        val state = callStack.popState()
         when (expression.operator) {
             IrTypeOperator.IMPLICIT_COERCION_TO_UNIT -> {
-                callStack.popState()
+                // do nothing
                 // callStack.pushState(getUnitState()) TODO find real use cases for this
             }
             IrTypeOperator.CAST, IrTypeOperator.IMPLICIT_CAST -> {
-                if (!isErased && !callStack.peekState()!!.isSubtypeOf(typeOperand)) {
-                    val convertibleClassName = callStack.popState().irClass.fqNameWhenAvailable
-                    ClassCastException("$convertibleClassName cannot be cast to ${typeOperand.render()}").handleUserException(environment)
+                when {
+                    state.isNull() && !typeOperand.isNullable() -> NullPointerException().handleUserException(environment)
+                    !isErased && !state.isSubtypeOf(typeOperand) -> {
+                        val castedClassName = state.irClass.fqNameWhenAvailable
+                        ClassCastException("$castedClassName cannot be cast to ${typeOperand.render()}").handleUserException(environment)
+                    }
+                    else -> callStack.pushState(state)
                 }
             }
             IrTypeOperator.SAFE_CAST -> {
-                if (!isErased && !callStack.peekState()!!.isSubtypeOf(typeOperand)) {
-                    callStack.popState()
-                    callStack.pushState(null.toState(irBuiltIns.nothingNType))
+                when {
+                    !isErased && !state.isSubtypeOf(typeOperand) -> callStack.pushState(null.toState(irBuiltIns.nothingNType))
+                    else -> callStack.pushState(state)
                 }
             }
             IrTypeOperator.INSTANCEOF -> {
-                val isInstance = callStack.popState().isSubtypeOf(typeOperand) || isErased
+                val isInstance = state.isSubtypeOf(typeOperand) || isErased
                 callStack.pushState(isInstance.toState(irBuiltIns.booleanType))
             }
             IrTypeOperator.NOT_INSTANCEOF -> {
-                val isInstance = callStack.popState().isSubtypeOf(typeOperand) || isErased
+                val isInstance = state.isSubtypeOf(typeOperand) || isErased
                 callStack.pushState((!isInstance).toState(irBuiltIns.booleanType))
             }
             IrTypeOperator.IMPLICIT_NOTNULL -> {
-
+                when {
+                    state.isNull() && !typeOperand.isNullable() -> NullPointerException().handleUserException(environment)
+                    else -> callStack.pushState(state)
+                }
             }
             else -> TODO("${expression.operator} not implemented")
         }
diff --git a/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/intrinsics/IntrinsicImplementations.kt b/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/intrinsics/IntrinsicImplementations.kt
index 8aa1eea2198..bec0d775528 100644
--- a/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/intrinsics/IntrinsicImplementations.kt
+++ b/compiler/ir/ir.interpreter/src/org/jetbrains/kotlin/ir/interpreter/intrinsics/IntrinsicImplementations.kt
@@ -290,6 +290,7 @@ internal object AssertIntrinsic : IntrinsicBase() {
 
         val messageLambda = environment.callStack.getState(irFunction.valueParameters.last().symbol) as KFunctionState
         val function = messageLambda.irFunction as IrSimpleFunction
+        environment.callStack.loadUpValues(messageLambda)
         val call = IrCallImpl.fromSymbolOwner(UNDEFINED_OFFSET, UNDEFINED_OFFSET, function.returnType, function.symbol)
 
         return listOf(customEvaluateInstruction(irFunction, environment), CompoundInstruction(call))
diff --git a/compiler/testData/ir/interpreter/exceptions/nullPointerException.kt b/compiler/testData/ir/interpreter/exceptions/nullPointerException.kt
index cc5471ae1bb..0885d5f85ab 100644
--- a/compiler/testData/ir/interpreter/exceptions/nullPointerException.kt
+++ b/compiler/testData/ir/interpreter/exceptions/nullPointerException.kt
@@ -38,6 +38,15 @@ fun notNullLambda(lambda: (() -> String)?): String {
     }
 }
 
+@CompileTimeCalculation
+fun nullableCast(str: String?): String {
+    return try {
+        str as String
+    } catch (e: NullPointerException) {
+        "Null"
+    }
+}
+
 const val a1 = <!EVALUATED: `Value isn't null`!>notNullAssertion(1)<!>
 const val a2 = <!EVALUATED: `Value is null`!>notNullAssertion(null)<!>
 const val b1 = <!EVALUATED: `Value isn't null`!>notNullAssertionForObject(A())<!>
@@ -46,3 +55,5 @@ const val c1 = <!EVALUATED: `Some text`!>notNullAssertionForSomeWrapper(StringBu
 const val c2 = <!EVALUATED: `Value is null`!>notNullAssertionForSomeWrapper(null)<!>
 const val d1 = <!EVALUATED: `Not null lambda`!>notNullLambda { "Not null lambda" }<!>
 const val d2 = <!EVALUATED: `Lambda is null`!>notNullLambda(null)<!>
+const val e1 = <!EVALUATED: `Not null String`!>nullableCast("Not null String")<!>
+const val e2 = <!EVALUATED: `Null`!>nullableCast(null)<!>