Function getSpreadArgumentType

test/fixtures/snapshot/typescript.js:75548–75586

(args, index, argCount, restType, context, checkMode)

                        createTupleType([type], [8 /* ElementFlags.Variadic */]);
        }
        function getSpreadArgumentType(args, index, argCount, restType, context, checkMode) {
            if (index >= argCount - 1) {
                var arg = args[argCount - 1];
                if (isSpreadArgument(arg)) {
                    // We are inferring from a spread expression in the last argument position, i.e. both the parameter
                    // and the argument are ...x forms.
                    return getMutableArrayOrTupleType(arg.kind === 232 /* SyntaxKind.SyntheticExpression */ ? arg.type :
                        checkExpressionWithContextualType(arg.expression, restType, context, checkMode));
                }
            }
            var types = [];
            var flags = [];
            var names = [];
            for (var i = index; i < argCount; i++) {
                var arg = args[i];
                if (isSpreadArgument(arg)) {
                    var spreadType = arg.kind === 232 /* SyntaxKind.SyntheticExpression */ ? arg.type : checkExpression(arg.expression);
                    if (isArrayLikeType(spreadType)) {
                        types.push(spreadType);
                        flags.push(8 /* ElementFlags.Variadic */);
                    }
                    else {
                        types.push(checkIteratedTypeOrElementType(33 /* IterationUse.Spread */, spreadType, undefinedType, arg.kind === 225 /* SyntaxKind.SpreadElement */ ? arg.expression : arg));
                        flags.push(4 /* ElementFlags.Rest */);
                    }
                }
                else {
                    var contextualType = getIndexedAccessType(restType, getNumberLiteralType(i - index), 256 /* AccessFlags.Contextual */);
                    var argType = checkExpressionWithContextualType(arg, contextualType, context, checkMode);
                    var hasPrimitiveContextualType = maybeTypeOfKind(contextualType, 131068 /* TypeFlags.Primitive */ | 4194304 /* TypeFlags.Index */ | 134217728 /* TypeFlags.TemplateLiteral */ | 268435456 /* TypeFlags.StringMapping */);
                    types.push(hasPrimitiveContextualType ? getRegularTypeOfLiteralType(argType) : getWidenedLiteralType(argType));
                    flags.push(1 /* ElementFlags.Required */);
                }
                if (arg.kind === 232 /* SyntaxKind.SyntheticExpression */ && arg.tupleNameSource) {
                    names.push(arg.tupleNameSource);
                }
            }
            return createTupleType(types, flags, /*readonly*/ false, ts.length(names) === ts.length(types) ? names : undefined);
        }
        function checkTypeArguments(signature, typeArgumentNodes, reportErrors, headMessage) {
            var isJavascript = ts.isInJSFile(signature.declaration);
            var typeParameters = signature.typeParameters;