The documentation claims that channel "cannot be used to specify custom toolchains or host-specific toolchains." at
https://rust-lang.github.io/rustup/overrides.html#channel
But it seems to work. Is anything subtly broken?
I have a symlink risc0 in ~/.rustup/toolchains, and put this in a rust-toolchain.toml:
[toolchain]
channel="risc0"
The symlink came from installing risc0 (by Installation | RISC Zero Developer Docs )