JVM_IR fix cast to not-null type

We can't rely on argument type nullability here, because it still can
hold an uninitialized value on JVM.

KT-50577 KT-35272 KT-27427

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -4685,6 +4685,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/casts/kt48987.kt");
         }
 
+        @Test
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @Test
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBytecodeTextTestGenerated.java

@@ -4686,6 +4686,12 @@ public class FirBytecodeTextTestGenerated extends AbstractFirBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/nullCheckOptimization/deterministicNotNullChecks.kt");
         }
 
+        @Test
+        @TestMetadata("exclExclAsNotNullType.kt")
+        public void testExclExclAsNotNullType() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/nullCheckOptimization/exclExclAsNotNullType.kt");
+        }
+
         @Test
         @TestMetadata("expressionValueIsNotNull.kt")
         public void testExpressionValueIsNotNull() throws Exception {

compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/TypeOperatorLowering.kt

@@ -83,7 +83,11 @@ private class TypeOperatorLowering(private val context: JvmBackendContext) : Fil
     private fun lowerCast(argument: IrExpression, type: IrType): IrExpression = when {
         type.isReifiedTypeParameter ->
             builder.irAs(argument, type)
-        argument.type.isNullable() && !type.isNullable() ->
+        argument.type.isInlineClassType() && argument.type.isSubtypeOfClass(type.erasedUpperBound.symbol) ->
+            argument
+        type.isNullable() || argument.isDefinitelyNotNull() ->
+            builder.irAs(argument, type)
+        else -> {
             with(builder) {
                 irLetS(argument, irType = context.irBuiltIns.anyNType) { valueSymbol ->
                     irIfNull(
@@ -92,14 +96,30 @@ private class TypeOperatorLowering(private val context: JvmBackendContext) : Fil
                         irCall(throwTypeCastException).apply {
                             putValueArgument(0, irString("null cannot be cast to non-null type ${type.render()}"))
                         },
-                        lowerCast(irGet(valueSymbol.owner), type.makeNullable())
+                        builder.irAs(irGet(valueSymbol.owner), type.makeNullable())
                     )
                 }
             }
-        argument.type.isInlineClassType() && argument.type.isSubtypeOfClass(type.erasedUpperBound.symbol) ->
-            argument
-        else ->
-            builder.irAs(argument, type)
+        }
+    }
+
+    // TODO extract null check elimination on IR somewhere?
+    private fun IrExpression.isDefinitelyNotNull(): Boolean =
+        when (this) {
+            is IrGetValue ->
+                this.symbol.owner.isDefinitelyNotNullVal()
+            is IrGetClass,
+            is IrConstructorCall ->
+                true
+            is IrCall ->
+                this.symbol == context.irBuiltIns.checkNotNullSymbol
+            else ->
+                false
+        }
+
+    private fun IrValueDeclaration.isDefinitelyNotNullVal(): Boolean {
+        val irVariable = this as? IrVariable ?: return false
+        return !irVariable.isVar && irVariable.initializer?.isDefinitelyNotNull() == true
     }
 
     private val jvmIndyLambdaMetafactoryIntrinsic = context.ir.symbols.indyLambdaMetafactoryIntrinsic

compiler/testData/codegen/box/casts/kt50577.kt

@@ -0,0 +1,26 @@
+abstract class A {
+    abstract val x: Any
+
+    init {
+        castX(this)
+    }
+}
+
+class B : A() {
+    override val x: Any = "abc"
+}
+
+fun castX(a: A) {
+    a.x as String
+}
+
+fun box(): String {
+    try {
+        B()
+    } catch (e: NullPointerException) {
+        return "OK"
+    } catch (e: ClassCastException) {
+        return "OK" // JS
+    }
+    return "Failed: should throw NPE"
+}

compiler/testData/codegen/bytecodeText/nullCheckOptimization/exclExclAsNotNullType.kt

@@ -0,0 +1,8 @@
+fun test(a: Any?) = a!! as String
+
+// 1 checkNotNull
+// JVM_IR_TEMPLATES
+// 0 IFNULL
+// 0 IFNONNULL
+// 0 NullPointerException
+// 0 ASTORE

compiler/testData/codegen/bytecodeText/nullCheckOptimization/noNullCheckAfterCast.kt

@@ -26,9 +26,4 @@ fun test3() {
 
 fun getB(): B = B()
 
-// JVM_TEMPLATES
 // 1 IFNONNULL
-
-// There should be no null checks in the bytecode.
-// JVM_IR_TEMPLATES
-// 0 IFNONNULL

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java

@@ -4577,6 +4577,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/casts/kt48927_privateMethodOnDerivedCastToBase.kt");
         }
 
+        @Test
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @Test
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BytecodeTextTestGenerated.java

@@ -4536,6 +4536,12 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/nullCheckOptimization/deterministicNotNullChecks.kt");
         }
 
+        @Test
+        @TestMetadata("exclExclAsNotNullType.kt")
+        public void testExclExclAsNotNullType() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/nullCheckOptimization/exclExclAsNotNullType.kt");
+        }
+
         @Test
         @TestMetadata("expressionValueIsNotNull.kt")
         public void testExpressionValueIsNotNull() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -4685,6 +4685,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/casts/kt48987.kt");
         }
 
+        @Test
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @Test
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBytecodeTextTestGenerated.java

@@ -4686,6 +4686,12 @@ public class IrBytecodeTextTestGenerated extends AbstractIrBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/nullCheckOptimization/deterministicNotNullChecks.kt");
         }
 
+        @Test
+        @TestMetadata("exclExclAsNotNullType.kt")
+        public void testExclExclAsNotNullType() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/nullCheckOptimization/exclExclAsNotNullType.kt");
+        }
+
         @Test
         @TestMetadata("expressionValueIsNotNull.kt")
         public void testExpressionValueIsNotNull() throws Exception {

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

@@ -3996,6 +3996,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/casts/kt48927_privateMethodOnDerivedCastToBase.kt");
         }
 
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {
             runTest("compiler/testData/codegen/box/casts/lambdaToUnitCast.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java

@@ -3371,6 +3371,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/casts/kt48927_privateMethodOnDerivedCastToBase.kt");
         }
 
+        @Test
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @Test
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java

@@ -3413,6 +3413,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/casts/kt48927_privateMethodOnDerivedCastToBase.kt");
         }
 
+        @Test
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @Test
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/testOld/wasm/semantics/IrCodegenBoxWasmTestGenerated.java

@@ -3016,6 +3016,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/casts/kt48927_privateMethodOnDerivedCastToBase.kt");
         }
 
+        @TestMetadata("kt50577.kt")
+        public void testKt50577() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+        }
+
         @TestMetadata("lambdaToUnitCast.kt")
         public void testLambdaToUnitCast() throws Exception {
             runTest("compiler/testData/codegen/box/casts/lambdaToUnitCast.kt");

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/ExternalTestGenerated.java

@@ -3487,6 +3487,12 @@ public class ExternalTestGenerated extends AbstractExternalNativeBlackBoxTest {
                 runTest("compiler/testData/codegen/box/casts/kt48927_privateMethodOnDerivedCastToBase.kt");
             }
 
+            @Test
+            @TestMetadata("kt50577.kt")
+            public void testKt50577() throws Exception {
+                runTest("compiler/testData/codegen/box/casts/kt50577.kt");
+            }
+
             @Test
             @TestMetadata("lambdaToUnitCast.kt")
             public void testLambdaToUnitCast() throws Exception {