tests/cases/compiler/incrementOnTypeParameter.ts(4,9): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. tests/cases/compiler/incrementOnTypeParameter.ts(5,39): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. ==== tests/cases/compiler/incrementOnTypeParameter.ts (2 errors) ==== class C { a: T; foo() { this.a++; ~~~~~~ !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. for (var i: T, j = 0; j < 10; i++) { ~ !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type. } } }