JS_IR: fix typecheck corner case

Consider `fun <E : I> foo(a: Any?) = a as? E`, where I is an interface.
This check used to fail, because the `a == null` was missing, and
the `isInterface` stdlib method crashes if the first argument
is null. This change adds the null check.

Also this change prettifies the instance check in case of type parameter
left operand.

compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/util/IrTypeUtils.kt

@@ -41,7 +41,7 @@ private fun IrType.isClassWithNamePrefix(prefix: String, packageFqName: FqName):
     return parent.fqName == packageFqName
 }
 
-private fun IrType.superTypes(): List<IrType> = classifierOrNull?.superTypes() ?: emptyList()
+fun IrType.superTypes(): List<IrType> = classifierOrNull?.superTypes() ?: emptyList()
 
 fun IrType.isFunctionTypeOrSubtype(): Boolean = DFS.ifAny(listOf(this), IrType::superTypes, IrType::isFunction)
 fun IrType.isSuspendFunctionTypeOrSubtype(): Boolean = DFS.ifAny(listOf(this), IrType::superTypes, IrType::isSuspendFunction)

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

@@ -151,6 +151,7 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
 
             // Note: native `instanceOf` is not used which is important because of null-behaviour
             private fun advancedCheckRequired(type: IrType) = type.isInterface() ||
+                    type.isTypeParameter() && type.superTypes().any { it.isInterface() } ||
                     type.isArray() ||
                     type.isPrimitiveArray() ||
                     isTypeOfCheckingType(type)
@@ -261,10 +262,16 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
 
                 // TODO either remove functions with reified type parameters or support this case
                 // assert(!typeParameter.isReified) { "reified parameters have to be lowered before" }
-                return typeParameter.superTypes.fold(litTrue) { r, t ->
+
+                return typeParameter.superTypes.fold<IrType, IrExpression?>(null) { r, t ->
                     val check = generateTypeCheckNonNull(argument.copy(), t.makeNotNull())
-                    calculator.and(r, check)
-                }
+
+                    if (r == null) {
+                        check
+                    } else {
+                        calculator.andand(r, check)
+                    }
+                } ?: litTrue
             }
 
 //            private fun generateCheckForChar(argument: IrExpression) =

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

@@ -0,0 +1,5 @@
+interface I
+
+fun <E: I> foo(a: Any?): E? = a as? E
+
+fun box() = foo<I>(null) ?: "OK"

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

@@ -2821,6 +2821,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/casts/notIs.kt");
         }
 
+        @TestMetadata("nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt")
+        public void testNullableSafeCastToTypeParameterWithInterfaceUpperBound() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt");
+        }
+
         @TestMetadata("unitAsAny.kt")
         public void testUnitAsAny() throws Exception {
             runTest("compiler/testData/codegen/box/casts/unitAsAny.kt");

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

@@ -2821,6 +2821,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/casts/notIs.kt");
         }
 
+        @TestMetadata("nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt")
+        public void testNullableSafeCastToTypeParameterWithInterfaceUpperBound() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt");
+        }
+
         @TestMetadata("unitAsAny.kt")
         public void testUnitAsAny() throws Exception {
             runTest("compiler/testData/codegen/box/casts/unitAsAny.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -2801,6 +2801,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/casts/notIs.kt");
         }
 
+        @TestMetadata("nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt")
+        public void testNullableSafeCastToTypeParameterWithInterfaceUpperBound() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt");
+        }
+
         @TestMetadata("unitAsAny.kt")
         public void testUnitAsAny() throws Exception {
             runTest("compiler/testData/codegen/box/casts/unitAsAny.kt");

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

@@ -2801,6 +2801,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/casts/notIs.kt");
         }
 
+        @TestMetadata("nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt")
+        public void testNullableSafeCastToTypeParameterWithInterfaceUpperBound() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt");
+        }
+
         @TestMetadata("unitAsAny.kt")
         public void testUnitAsAny() throws Exception {
             runTest("compiler/testData/codegen/box/casts/unitAsAny.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -2246,6 +2246,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/casts/notIs.kt");
         }
 
+        @TestMetadata("nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt")
+        public void testNullableSafeCastToTypeParameterWithInterfaceUpperBound() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt");
+        }
+
         @TestMetadata("unitAsAny.kt")
         public void testUnitAsAny() throws Exception {
             runTest("compiler/testData/codegen/box/casts/unitAsAny.kt");

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

@@ -2246,6 +2246,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/casts/notIs.kt");
         }
 
+        @TestMetadata("nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt")
+        public void testNullableSafeCastToTypeParameterWithInterfaceUpperBound() throws Exception {
+            runTest("compiler/testData/codegen/box/casts/nullableSafeCastToTypeParameterWithInterfaceUpperBound.kt");
+        }
+
         @TestMetadata("unitAsAny.kt")
         public void testUnitAsAny() throws Exception {
             runTest("compiler/testData/codegen/box/casts/unitAsAny.kt");

libraries/tools/kotlinp/test/org/jetbrains/kotlin/kotlinp/test/KotlinpTestGenerated.java

@@ -25,7 +25,7 @@ public class KotlinpTestGenerated extends AbstractKotlinpTest {
     }
 
     public void testAllFilesPresentInTestData() throws Exception {
-        KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("libraries/tools/kotlinp/testData"), Pattern.compile("^(.+)\\.kt$"), true);
+        KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("libraries/tools/kotlinp/testData"), Pattern.compile("^(.+)\\.kt$"), null, true);
     }
 
     @TestMetadata("Annotations.kt")