Function checkTypePredicate

test/fixtures/snapshot/typescript.js:80096–80141

(node)

            }
        }
        function checkTypePredicate(node) {
            var parent = getTypePredicateParent(node);
            if (!parent) {
                // The parent must not be valid.
                error(node, ts.Diagnostics.A_type_predicate_is_only_allowed_in_return_type_position_for_functions_and_methods);
                return;
            }
            var signature = getSignatureFromDeclaration(parent);
            var typePredicate = getTypePredicateOfSignature(signature);
            if (!typePredicate) {
                return;
            }
            checkSourceElement(node.type);
            var parameterName = node.parameterName;
            if (typePredicate.kind === 0 /* TypePredicateKind.This */ || typePredicate.kind === 2 /* TypePredicateKind.AssertsThis */) {
                getTypeFromThisTypeNode(parameterName);
            }
            else {
                if (typePredicate.parameterIndex >= 0) {
                    if (signatureHasRestParameter(signature) && typePredicate.parameterIndex === signature.parameters.length - 1) {
                        error(parameterName, ts.Diagnostics.A_type_predicate_cannot_reference_a_rest_parameter);
                    }
                    else {
                        if (typePredicate.type) {
                            var leadingError = function () { return ts.chainDiagnosticMessages(/*details*/ undefined, ts.Diagnostics.A_type_predicate_s_type_must_be_assignable_to_its_parameter_s_type); };
                            checkTypeAssignableTo(typePredicate.type, getTypeOfSymbol(signature.parameters[typePredicate.parameterIndex]), node.type, 
                            /*headMessage*/ undefined, leadingError);
                        }
                    }
                }
                else if (parameterName) {
                    var hasReportedError = false;
                    for (var _i = 0, _a = parent.parameters; _i < _a.length; _i++) {
                        var name = _a[_i].name;
                        if (ts.isBindingPattern(name) &&
                            checkIfTypePredicateVariableIsDeclaredInBindingPattern(name, parameterName, typePredicate.parameterName)) {
                            hasReportedError = true;
                            break;
                        }
                    }
                    if (!hasReportedError) {
                        error(node.parameterName, ts.Diagnostics.Cannot_find_parameter_0, typePredicate.parameterName);
                    }
                }
            }
        }
        function getTypePredicateParent(node) {
            switch (node.parent.kind) {
                case 214 /* SyntaxKind.ArrowFunction */: