tests/cases/conformance/es6/spread/iteratorSpreadInArray6.ts(2,14): error TS2345: Argument of type 'symbol[]' is not assignable to parameter of type 'number'. ==== tests/cases/conformance/es6/spread/iteratorSpreadInArray6.ts (1 errors) ==== var array: number[] = [0, 1]; array.concat([...new SymbolIterator]); ~~~~~~~~~~~~~~~~~~~~~~~ !!! error TS2345: Argument of type 'symbol[]' is not assignable to parameter of type 'number'. class SymbolIterator { next() { return { value: Symbol(), done: false }; } [Symbol.iterator]() { return this; } }