Function maybeAddJsSyntheticRestParameter

test/fixtures/snapshot/typescript.js:59702–59731

* A JS function gets a synthetic rest parameter if it references `arguments` AND: * 1. It has no parameters but at least one `@param` with a type that starts with `...` * OR * 2. It has at least one parameter, and the last parameter has a matching `@param` with a type that

(declaration, parameters)

         * 2. It has at least one parameter, and the last parameter has a matching `@param` with a type that starts with `...`
         */
        function maybeAddJsSyntheticRestParameter(declaration, parameters) {
            if (ts.isJSDocSignature(declaration) || !containsArgumentsReference(declaration)) {
                return false;
            }
            var lastParam = ts.lastOrUndefined(declaration.parameters);
            var lastParamTags = lastParam ? ts.getJSDocParameterTags(lastParam) : ts.getJSDocTags(declaration).filter(ts.isJSDocParameterTag);
            var lastParamVariadicType = ts.firstDefined(lastParamTags, function (p) {
                return p.typeExpression && ts.isJSDocVariadicType(p.typeExpression.type) ? p.typeExpression.type : undefined;
            });
            var syntheticArgsSymbol = createSymbol(3 /* SymbolFlags.Variable */, "args", 32768 /* CheckFlags.RestParameter */);
            if (lastParamVariadicType) {
                // Parameter has effective annotation, lock in type
                syntheticArgsSymbol.type = createArrayType(getTypeFromTypeNode(lastParamVariadicType.type));
            }
            else {
                // Parameter has no annotation
                // By using a `DeferredType` symbol, we allow the type of this rest arg to be overriden by contextual type assignment so long as its type hasn't been
                // cached by `getTypeOfSymbol` yet.
                syntheticArgsSymbol.checkFlags |= 65536 /* CheckFlags.DeferredType */;
                syntheticArgsSymbol.deferralParent = neverType;
                syntheticArgsSymbol.deferralConstituents = [anyArrayType];
                syntheticArgsSymbol.deferralWriteConstituents = [anyArrayType];
            }
            if (lastParamVariadicType) {
                // Replace the last parameter with a rest parameter.
                parameters.pop();
            }
            parameters.push(syntheticArgsSymbol);
            return true;
        }
        function getSignatureOfTypeTag(node) {
            // should be attached to a function declaration or expression
            if (!(ts.isInJSFile(node) && ts.isFunctionLikeDeclaration(node)))