JS: chained reified function calls (KT-12527) fixed

compiler/testData/codegen/box/reified/reifiedChain.kt

@@ -0,0 +1,36 @@
+inline fun <reified T> Any?.check(): Boolean {
+    return this is T
+}
+
+inline fun <reified T> Any?.check2(): Boolean {
+    return check<T>()
+}
+
+
+var log = ""
+fun log(a: Any?) {
+    log += a.toString() + ";"
+}
+
+fun test(a: Any?) {
+    log(a.check<String>())
+    log(a.check<String?>())
+}
+
+fun test2(a: Any?) {
+    log(a.check2<String>())
+    log(a.check2<String?>())
+}
+
+fun box(): String {
+    test("")
+    test(null)
+    test2("")
+    test2(null)
+
+    if (log != "true;true;false;true;true;true;false;true;") {
+        return "fail"
+    }
+
+    return "OK"
+}

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

@@ -14540,6 +14540,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("reifiedChain.kt")
+        public void testReifiedChain() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reified/reifiedChain.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("reifiedInlineFunOfObject.kt")
         public void testReifiedInlineFunOfObject() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reified/reifiedInlineFunOfObject.kt");

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

@@ -14540,6 +14540,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("reifiedChain.kt")
+        public void testReifiedChain() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reified/reifiedChain.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("reifiedInlineFunOfObject.kt")
         public void testReifiedInlineFunOfObject() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reified/reifiedInlineFunOfObject.kt");

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

@@ -19112,6 +19112,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
         }
 
+        @TestMetadata("reifiedChain.kt")
+        public void testReifiedChain() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reified/reifiedChain.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("reifiedInlineFunOfObject.kt")
         public void testReifiedInlineFunOfObject() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/reified/reifiedInlineFunOfObject.kt");

js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/PatternTranslator.java

@@ -138,7 +138,9 @@ public final class PatternTranslator extends AbstractTranslator {
     public JsExpression getIsTypeCheckCallable(@NotNull KotlinType type) {
         JsExpression callable = doGetIsTypeCheckCallable(type);
 
-        if (isNullableType(type)) {
+        // If the type is reified, rely on the corresponding is type callable.
+        // Otherwise make sure that passing null yields true
+        if (!isReifiedTypeParameter(type) && isNullableType(type)) {
             return namer().orNull(callable);
         }