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

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);
         }