2 1 = 2; //~ ERROR invalid left-hand side of assignment
3 1 += 2; //~ ERROR invalid left-hand side of assignment
4 (1, 2) = (3, 4); //~ ERROR destructuring assignments are unstable
5 //~| ERROR invalid left-hand side of assignment
6 //~| ERROR invalid left-hand side of assignment
9 (a, b) = (3, 4); //~ ERROR destructuring assignments are unstable
11 None = Some(3); //~ ERROR invalid left-hand side of assignment