Reified 'as?' produces nullable result

Previously, this was treated as a regular CHECKCAST, causing KT-22410.

 #Fixed KT-22410 Target versions 1.2.30

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/ReifiedTypeInliner.kt

@@ -261,7 +261,7 @@ val MethodInsnNode.reificationArgument: ReificationArgument?
         return ReificationArgument(parameterName, nullable, arrayDepth)
     }
 
-private val MethodInsnNode.operationKind: ReifiedTypeInliner.OperationKind? get() =
+val MethodInsnNode.operationKind: ReifiedTypeInliner.OperationKind? get() =
     previous?.previous?.intConstant?.let {
         ReifiedTypeInliner.OperationKind.values().getOrNull(it)
     }

compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/nullCheck/NullabilityInterpreter.kt

@@ -16,6 +16,8 @@
 
 package org.jetbrains.kotlin.codegen.optimization.nullCheck
 
+import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner
+import org.jetbrains.kotlin.codegen.inline.operationKind
 import org.jetbrains.kotlin.codegen.optimization.boxing.*
 import org.jetbrains.kotlin.codegen.optimization.common.OptimizationBasicInterpreter
 import org.jetbrains.kotlin.codegen.optimization.common.StrictBasicValue
@@ -24,6 +26,7 @@ import org.jetbrains.kotlin.codegen.pseudoInsns.isPseudo
 import org.jetbrains.org.objectweb.asm.Opcodes
 import org.jetbrains.org.objectweb.asm.Type
 import org.jetbrains.org.objectweb.asm.tree.AbstractInsnNode
+import org.jetbrains.org.objectweb.asm.tree.MethodInsnNode
 import org.jetbrains.org.objectweb.asm.tree.TypeInsnNode
 import org.jetbrains.org.objectweb.asm.tree.analysis.BasicValue
 
@@ -53,16 +56,25 @@ class NullabilityInterpreter : OptimizationBasicInterpreter() {
         val defaultResult = super.unaryOperation(insn, value)
         val resultType = defaultResult?.type
 
-        return when {
-            insn.opcode == Opcodes.CHECKCAST ->
-                value
-            insn.opcode == Opcodes.NEWARRAY || insn.opcode == Opcodes.ANEWARRAY ->
+        return when (insn.opcode) {
+            Opcodes.CHECKCAST ->
+                if (insn.isReifiedSafeAs())
+                    StrictBasicValue(resultType)
+                else
+                    value
+            Opcodes.NEWARRAY, Opcodes.ANEWARRAY ->
                 NotNullBasicValue(resultType)
             else ->
                 defaultResult
         }
     }
 
+    private fun AbstractInsnNode.isReifiedSafeAs(): Boolean {
+        val marker = previous as? MethodInsnNode ?: return false
+        return ReifiedTypeInliner.isOperationReifiedMarker(marker)
+                && marker.operationKind == ReifiedTypeInliner.OperationKind.SAFE_AS
+    }
+
     override fun naryOperation(insn: AbstractInsnNode, values: List<BasicValue>): BasicValue? {
         val defaultResult = super.naryOperation(insn, values)
         val resultType = defaultResult?.type

compiler/testData/codegen/box/nullCheckOptimization/kt22410.kt

@@ -0,0 +1,20 @@
+fun box(): String {
+    defineFunc<String>()
+
+    func(1)
+
+    return if (testedEquals) "OK" else "Fail"
+}
+
+var func: (Any) -> Unit = {}
+
+var testedEquals = false
+
+inline fun <reified T> defineFunc() {
+    func = {
+        val nullable = it as? T
+
+        if (nullable == null)
+            testedEquals = true
+    }
+}

compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -12672,6 +12672,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("kt22410.kt")
+        public void testKt22410() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt22410.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt7774.kt")
         public void testKt7774() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt7774.kt");

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -12672,6 +12672,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("kt22410.kt")
+        public void testKt22410() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt22410.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt7774.kt")
         public void testKt7774() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt7774.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -12672,6 +12672,12 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             doTest(fileName);
         }
 
+        @TestMetadata("kt22410.kt")
+        public void testKt22410() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt22410.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt7774.kt")
         public void testKt7774() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt7774.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -13776,6 +13776,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             doTest(fileName);
         }
 
+        @TestMetadata("kt22410.kt")
+        public void testKt22410() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt22410.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt7774.kt")
         public void testKt7774() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/nullCheckOptimization/kt7774.kt");