1 error[E0368]: binary assignment operation `+=` cannot be applied to type `T`
2 --> $DIR/issue-6738.rs:16:9
7 | cannot use `+=` on type `T`
9 = note: `T` might need a bound for `std::ops::AddAssign`
11 error: aborting due to previous error
13 For more information about this error, try `rustc --explain E0368`.