Incidentally I saw this rolling away on my screen. writing byte-compilation script '/scratch/var/tmp/portage/dev-python/jinja-2.10/temp/tmpwprd9gbe.py' /usr/bin/python3.5 -O /scratch/var/tmp/portage/dev-python/jinja-2.10/temp/tmpwprd9gbe.py File "/usr/lib64/python3.5/site-packages/jinja2/asyncfilters.py", line 24 yield item ^ SyntaxError: 'yield' inside async function File "/usr/lib64/python3.5/site-packages/jinja2/asyncsupport.py", line 35 yield event ^ SyntaxError: 'yield' inside async function removing /scratch/var/tmp/portage/dev-python/jinja-2.10/temp/tmpwprd9gbe.py writing byte-compilation script '/scratch/var/tmp/portage/dev-python/jinja-2.10/temp/tmpp5bxuqkv.py' /usr/bin/python3.5 -OO /scratch/var/tmp/portage/dev-python/jinja-2.10/temp/tmpp5bxuqkv.py File "/usr/lib64/python3.5/site-packages/jinja2/asyncfilters.py", line 24 yield item ^ SyntaxError: 'yield' inside async function File "/usr/lib64/python3.5/site-packages/jinja2/asyncsupport.py", line 35 yield event ^ SyntaxError: 'yield' inside async function removing /scratch/var/tmp/portage/dev-python/jinja-2.10/temp/tmpp5bxuqkv.py running install_egg_info Copying Jinja2.egg-info to /scratch/var/tmp/portage/dev-python/jinja-2.10/image/_python3.5/usr/lib64/python3.5/site-packages/Jinja2-2.10-py3.5.egg-info running install_scripts File "/usr/lib64/python3.5/site-packages/jinja2/asyncfilters.py", line 24 yield item ^ SyntaxError: 'yield' inside async function File "/usr/lib64/python3.5/site-packages/jinja2/asyncsupport.py", line 35 yield event ^ SyntaxError: 'yield' inside async function * python3_5: running distutils-r1_run_phase python_install_all >>> Completed installing jinja-2.10 into /scratch/var/tmp/portage/dev-python/jinja-2.10/image/ * Final size of build directory: 2448 KiB (2.3 MiB) * Final size of installed tree: 3160 KiB (3.0 MiB) ecompressdir: bzip2 -9 /usr/share/doc >>> Installing (104 of 264) dev-python/jinja-2.10::gentoo
It's not a problem to have syntax error during compile time: this unit is conditionally imported and thus not used in py < 3.6: https://github.com/pallets/jinja/blob/fb7e12cce67b9849899f934e697f7e2a91d604c2/jinja2/environment.py#L337