Prerequisites for Windows


To build Idris 2 on Windows, an Unix-like environment is needed for all the utilities used during the build. MSYS2 provides that for us.

  1. Download the latest version of MSYS2

  2. Run the installer. Don’t install it under Program files as it needs to write files (the “unix” home directory lies under there, for example)

  3. In the directory where you installed MSYS2, find the file mingw64.ini and add the line MSYS2_PATH_TYPE=inherit. This adds the normal windows PATH to the shell in MSYS2.

  4. Start MSYS2 (click on mingw64.exe, as the icon in the start menu won’t pick up the MSYS2_PATH_TYPE from the ini, it can be added to the system settings)

  5. Update the installation with the latest releases with pacman -Syu

  6. Install the programs that the build needs with:

    $ pacman -S make mingw-w64-x86_64-gcc

Chez Scheme

Chez Scheme has a ready-made installer at GitHub

  1. Download the installer and run it, do not install it in a path with spaces, currently Idris2 has trouble with them.

  2. Add the threaded 64-bit scheme to the PATH. It is the \bin\ta6nt subdirectory to where Chez Scheme was installed. So if you used “C:Chez” it will be in C:\Chez\bin\ta6nt


  1. Start a fresh MSYS2 shell so that it knows about your modified PATH (it’s important to use Mingw64 to get access to the right compilers).

  2. Navigate to the Idris2 directory.

  3. Set the SCHEME environment variable that Idris2 needs export SCHEME=scheme. This can be set permanently in the bash profile file or the Windows settings.

  4. Now make bootstrap && make install should build Idris2 and install it in home/<username>/.idris2/bin under your MSYS2 installation. If you add that to the PATH in Windows settings it will be usable from any command line (including Powershell or DOS), that you open.