HOWTO: Rustup: Overriding the rustc compiler version just for some directory

If you need to use a specific version of the rustc compiler instead of the default, the rustup documentation tells you how to do that.


First install the desired version, e.g. nightly-2018-01-09

$ rustup install nightly-2018-01-09
info: syncing channel updates for 'nightly-2018-01-09-x86_64-pc-windows-msvc'
info: latest update on 2018-01-09, rust version 1.25.0-nightly (b5392f545 2018-01-08)
info: downloading component 'rustc'
info: downloading component 'rust-std'
info: downloading component 'cargo'
info: downloading component 'rust-docs'
info: installing component 'rustc'
info: installing component 'rust-std'
info: installing component 'cargo'
info: installing component 'rust-docs'

  nightly-2018-01-09-x86_64-pc-windows-msvc installed - rustc 1.25.0-nightly (b5392f545 2018-01-08)

info: checking for self-updates

Then override the default compiler with the desired one in the top directory of your choice:

$ rustup override set nightly-2018-01-09
info: using existing install for 'nightly-2018-01-09-x86_64-pc-windows-msvc'
info: override toolchain for 'C:\usr\src\rust\sbenitez-cs140e' set to 'nightly-2018-01-09-x86_64-pc-windows-msvc'

  nightly-2018-01-09-x86_64-pc-windows-msvc unchanged - rustc 1.25.0-nightly (b5392f545 2018-01-08)

That's it.