Note that the type is called `t` since the convention at the time was to name the primary type of a module `t` and then refer to the type as `modulename::t` (shows how far we've come, eh?). At this initial stage the variants are named `ok` and `error`. Also note that at this point in history Rust had had an `either` type for a while (https://github.com/rust-lang/rust/blob/c1092fb6d88efe51e42df...), which would later be removed as Result gained more traction.
Also interesting to note in the context of the union type discussions below is the use of the `tag` keyword as opposed to the current `enum` for declaring tagged unions.
At one point we were trying to name every part of a union type in Elm. Calling things "tags" instead of "constructors" seemed quite nice, but ultimately, it seemed like we couldn't get the perfect name.
Here's the first instance of what would become Rust's `Result` type (Oct 28 2011): https://github.com/rust-lang/rust/commit/c1092fb6d88efe51e42...
Note that the type is called `t` since the convention at the time was to name the primary type of a module `t` and then refer to the type as `modulename::t` (shows how far we've come, eh?). At this initial stage the variants are named `ok` and `error`. Also note that at this point in history Rust had had an `either` type for a while (https://github.com/rust-lang/rust/blob/c1092fb6d88efe51e42df...), which would later be removed as Result gained more traction.
Here's the commit where the `error` variant is renamed to `err` (Oct 28 2011, so the same day): https://github.com/rust-lang/rust/commit/2b62a80202e2855d47f...
Here's the first instance of `std::result` being mentioned in the mailing list (Nov 14 2011): http://article.gmane.org/gmane.comp.lang.rust.devel/891
Where the type itself is renamed to `result` (Mar 13 2012): https://github.com/rust-lang/rust/commit/b968c8e6cd362567bf0...
Where the type and variant names are capitalized in accordance with the current style guide (Aug 26 2012): https://github.com/rust-lang/rust/commit/0c6e470a257fc546555...
So this convention may very well have originated with Rust.