tests/cases/conformance/es6/Symbols/symbolType4.ts(2,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. tests/cases/conformance/es6/Symbols/symbolType4.ts(3,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. ==== tests/cases/conformance/es6/Symbols/symbolType4.ts (2 errors) ==== var s = Symbol.for("postfix"); s++; ~ !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. s--; ~ !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.