Error compiling my TypeScript file: error TS5011

My code in the file say.ts:

function say(person) {
    return "Hello" + person;
}

var user = "Gabriel Lemos";

console.log(say(user));

When I tried to compile:

  

tsc say.ts

I had the error: path \ say.js (1,1): error TS5011: Emit Error: Failed to write to file ..