let type aliases declared inside a function be available for parameters and the result type

[zpdDG4gta8XKpMCd]

consider

// currently have to deal with
export function glueAllHomoDiffs<a>(diffs: edf.HomoDifference<NativeSet<a>>[]): edf.HomoDifference<NativeSet<a>> {
    return ea.fold(
        diffs,
        edf.toHomoNoneOf<NativeSet<a>>(),
        (result, diff) => edf.glueHomoDifference(result, diff, glue, shallowCopy)
    );
}


// wish could do
export function glueAllHomoDiffs<a>(diffs: Difference[]): Difference {

    type Selection = NativeSet<a>;
    type Difference = edf.HomoDifference<Selection>;

    return ea.fold(
        diffs,
        edf.toHomoNoneOf<Selection>(),
        (result, diff) => edf.glueHomoDifference(result, diff, glue, shallowCopy)
    );
}

[mhegazy]

Same as my response to #7061 (#7061 (comment)). This should be easily defined using a type alias declaration outside the function, and not worth changing the scopign rules e.g.:

type Selection<a> = NativeSet<a>;
type Difference<a> = edf.HomoDifference<Selection<a>>;
export function glueAllHomoDiffs<a>(diffs: Difference<a>[]): Difference<a> {
...

[zpdDG4gta8XKpMCd]

it's all fun and games when there is only a which is indeed simple, let me close it and reopen when i find a better example