bug#49127: Performance degradation in encode_coding_object

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Wed, 18 Aug 2021 13:04:12 +0200
> Cc: victor.nawothnig@icloud.com, 49127@debbugs.gnu.org
> 
> consider an index of all definitions and uses of each variable, function and 
> type in a program, produced by an expensive compilation that cannot be re-run 
> for each little change. This could easily amount to thousands of markers in a 
> big file.

They could have used text properties instead, no?