bug#53459: error while installing with existing partitions

[Néstor Arocha]

Hi, 

I was trying to get guix installed on my x86_64 machine. (icore 3, 16Gb
RAM, 1TB ssd, ethernet working, using the guix curses installer)

Originally I tried as the only distribution in the system, but grub-efi
wouldn't get installed or recognised by the bios on boot.

Instead I decided to install debian on the first 500Gb and guix on the
second half. My idea is that by sharing the boot/efi partition and
debian managing the boot I would be able to boot guix as well

Debian created the following partitions
 1 537mb fat32 /boot/efi
 2 512mb ext2 /boot
 3 500GB encrypted volume


Then with guix I manually added the 4th partition as encrypted volume
with / mount point.

After the guix installer ask for the password for the new encrypted volume, I'd 
see the following error:

```
ice-9/eval.scm:159:9: Throw to key 'match-error' with args '("match" "no 
matching pattern" (#f ext4))'
```

I have attached a literal screenshot with the whole backtrace.

Any suggestions on how to go forward?

Thanks,

Nestor

guix_backtrace.png
Description: PNG image