* [Mktemp not working properly on macOS](https://gitlab.haskell.org/haskell/ghcup/issues/130)
* [ln: illegal option -- T on macOS Catalina](https://gitlab.haskell.org/haskell/ghcup/issues/123)
* [Wrong tar flag on darwin](https://gitlab.haskell.org/haskell/ghcup/issues/119))
* refactoring being difficult due to POSIX sh
More benefits of a rewrite:
* Features such as installing [release candidates](https://gitlab.haskell.org/haskell/ghcup/issues/94) or [HEAD builds](https://gitlab.haskell.org/haskell/ghcup/issues/65) can be more conveniently implemented in a rewrite
* Refactoring will be easier
* Better tool support (such as linting the downloads file)
* saner downloads file format (such as JSON)
However, the downside will be:
* building static binaries for all platforms (and possibly causing SSL/DNS problems)
* still bootstrapping those binaries via a POSIX sh script
## Goals
* Correct low-level code
* Good exception handling
* Easier user interface (possibly interactive and non-interactive ones)