TLDR: if you have this problem today, open /etc/pacman.d/mirrorlist and copy one of the commented-out parabola mirrors to the top of the mirrorlist - then pacman -Syu

the 'guile' package from arch was upgraded yesterday but the parabola repos still have the previous version, and the redirector can not find any arch mirror with that package - it is a dependency of 'make', so a rather important package

https://www.archlinux.org/packages/extra/x86_64/guile/

today someone reported several haskel packages with the same situation

perhaps related: i removed the 'gnutls-guile' package from the repos yesterday but the parabola mirrors still have it

anyone using the redirector with these packages installed will not be able to upgrade

error: failed retrieving file <P> from redirector.parabola.nu : The requested URL returned error: 404
warning: failed to retrieve some files

where the currently known <P>'s are:
'cabal-install-2.4.0.0-108-x86_64.pkg.tar.xz'
'guile-2.2.5-1-x86_64.pkg.tar.xz'
'haskell-http-4000.3.14-4-x86_64.pkg.tar.xz'
'haskell-conduit-extra-1.3.2-4-x86_64.pkg.tar.xz'
'haskell-cryptohash-conduit-0.1.1-283-x86_64.pkg.tar.xz'
'haskell-cryptonite-conduit-0.2.2-177-x86_64.pkg.tar.xz'
'haskell-http-conduit-2.3.7.1-34-x86_64.pkg.tar.xz'
'haskell-microlens-0.4.11.2-1-x86_64.pkg.tar.xz' 
'haskell-monad-logger-0.3.30-63-x86_64.pkg.tar.xz'
'haskell-persistent-2.9.2-35-x86_64.pkg.tar.xz'
'haskell-persistent-sqlite-2.9.3-36-x86_64.pkg.tar.xz'
'haskell-persistent-template-2.6.0-52-x86_64.pkg.tar.xz'
'haskell-project-template-0.2.0.1-149-x86_64.pkg.tar.xz'
'haskell-rio-0.1.9.2-19-x86_64.pkg.tar.xz'
'haskell-typed-process-0.2.5.0-2-x86_64.pkg.tar.xz'
'pandoc-2.7.3-6-x86_64.pkg.tar.xz'
'stack-1.9.3.1-76-x86_64.pkg.tar.xz'