Weird error after updating rustc (or updating windows)

If I try run cargo c or build or run (or anything involving compiling) in any project (even a new blank project)

error: could not execute process `rustc -vV` (never executed)

Caused by:
  The system cannot find the file specified. (os error 2)

Another symptom, when running rustup show

Default host: x86_64-pc-windows-msvc
rustup home:  C:\Users\username\.rustup

installed toolchains
--------------------

stable-x86_64-pc-windows-msvc
nightly-x86_64-pc-windows-msvc (default)

active toolchain
----------------

nightly-x86_64-pc-windows-msvc (default)
(error reading rustc version)

This line seems weird (error reading rustc version)

It seems like this means rustc doesn't exist, but it definitely does

From the same shell I can run rustc -vV and get the following, no problems

rustc 1.50.0-nightly (1700ca07c 2020-12-08)
binary: rustc
commit-hash: 1700ca07c6dd7becff85678409a5df6ad4cf4f47
commit-date: 2020-12-08
host: x86_64-pc-windows-msvc
release: 1.50.0-nightly

Searching for these errors I mostly find stuff from a long time ago that just says, 'It has been fixed in some commit'

I have reinstalled the toolchain and reinstalled rustup entirely, the same error happens