Tuple type-annotated rest parameters assertion failure ("Did not expect BoundT")

[samwgoldman]

/* @flow */
function oops<T>(...xs: [T]): void { }

/* @flow */
type Fn = <T>(...xs: [T]) => void;

/* @flow */
class A<T> { f(...xs: [T]): void {}; }

Output:

<<<<<<<<
Did not expect BoundT:
Called from file "list.ml", line 73, characters 12-15
>>>>>>>>

/path/to/test.js:
Failure("Did not expect BoundT")

[samwgoldman]

The above examples show my confusion between Array<T> and [T] types, the latter being a single element tuple type, which is an unsuitable annotation for rest parameters. However, the error message is unhelpful—PR attempts to address this.