You can find the C code in this temporary file: /run/user/1000/theano_compilation_error_fvjx9y_e
Traceback (most recent call last):
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/gof/lazylinker_c.py", line 81, in <module>
    actual_version, force_compile, _need_reload))
ImportError: Version check of the existing lazylinker compiled file. Looking for version 0.211, but found None. Extra debug information: force_compile=False, _need_reload=True

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/gof/lazylinker_c.py", line 105, in <module>
    actual_version, force_compile, _need_reload))
ImportError: Version check of the existing lazylinker compiled file. Looking for version 0.211, but found None. Extra debug information: force_compile=False, _need_reload=True

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/__init__.py", line 110, in <module>
    from theano.compile import (
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/compile/__init__.py", line 12, in <module>
    from theano.compile.mode import *
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/compile/mode.py", line 11, in <module>
    import theano.gof.vm
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/gof/vm.py", line 674, in <module>
    from . import lazylinker_c
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/gof/lazylinker_c.py", line 140, in <module>
    preargs=args)
  File "/nix/store/pf0dk0bjk0sgmwsskyqh57g79y3jrrbn-python3-3.7.6-env/lib/python3.7/site-packages/theano/gof/cmodule.py", line 2396, in compile_str
    (status, compile_stderr.replace('\n', '. ')))
Exception: Compilation failed (return status=1): impure path `/run/user/1000/ccX90FGJ.o' used in link. collect2: error: ld returned 1 exit status. 

 - system: `"x86_64-linux"`
 - host os: `Linux 5.7.4-arch1-1, Arch Linux, noversion`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.6`
 - channels(arthur): `""`
 - channels(root): `"nixpkgs-20.03.2310.fb6c3a6831c"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixpkgs`