This issue was initially reported here: eslint/typescript-eslint-parser#475

What version of TypeScript are you using?
2.8.3

What version of typescript-eslint-parser are you using?
15.0.0

What code were you trying to parse?

// Unexpected error: arrow-parens
const bar = <T>(t: T) => {};
// No error as expected
const bar2 = function <T>(t: T) {};