Function classDeclarationExtendsNull

test/fixtures/snapshot/typescript.js:71918–71923

* Check if the given class-declaration extends null then return true. * Otherwise, return false * @param classDecl a class declaration to check if it extends null

(classDecl)

         * @param classDecl a class declaration to check if it extends null
         */
        function classDeclarationExtendsNull(classDecl) {
            var classSymbol = getSymbolOfNode(classDecl);
            var classInstanceType = getDeclaredTypeOfSymbol(classSymbol);
            var baseConstructorType = getBaseConstructorTypeOfClass(classInstanceType);
            return baseConstructorType === nullWideningType;
        }
        function checkThisBeforeSuper(node, container, diagnosticMessage) {
            var containingClassDecl = container.parent;
            var baseTypeNode = ts.getClassExtendsHeritageElement(containingClassDecl);