Function checkAssertionWorker

test/fixtures/snapshot/typescript.js:77320–77340

(errNode, type, expression, checkMode)

            return false;
        }
        function checkAssertionWorker(errNode, type, expression, checkMode) {
            var exprType = checkExpression(expression, checkMode);
            if (ts.isConstTypeReference(type)) {
                if (!isValidConstAssertionArgument(expression)) {
                    error(expression, ts.Diagnostics.A_const_assertions_can_only_be_applied_to_references_to_enum_members_or_string_number_boolean_array_or_object_literals);
                }
                return getRegularTypeOfLiteralType(exprType);
            }
            checkSourceElement(type);
            exprType = getRegularTypeOfObjectLiteral(getBaseTypeOfLiteralType(exprType));
            var targetType = getTypeFromTypeNode(type);
            if (!isErrorType(targetType)) {
                addLazyDiagnostic(function () {
                    var widenedType = getWidenedType(exprType);
                    if (!isTypeComparableTo(targetType, widenedType)) {
                        checkTypeComparableTo(exprType, targetType, errNode, ts.Diagnostics.Conversion_of_type_0_to_type_1_may_be_a_mistake_because_neither_type_sufficiently_overlaps_with_the_other_If_this_was_intentional_convert_the_expression_to_unknown_first);
                    }
                });
            }
            return targetType;
        }
        function checkNonNullChain(node) {
            var leftType = checkExpression(node.expression);
            var nonOptionalType = getOptionalExpressionType(leftType, node.expression);