Pathological import symbol shadowing

[Kagamin]

On Wednesday, 18 November 2020 at 10:14:44 UTC, FeepingCreature 
wrote:
> This is why our style guide doesn't allow unqualified imports 
> in functions. The more I think about it, the more I suspect 
> function local imports were just a mistake to begin with.

No way, they are correctness and performance feature. Look at STL 
to see what happens when everything is visible.