Could proxy methods override object type(s)?

[tobiasziegler]

The compare_proxy methods are currently called after types have been compared, which means a proxy method can't have any effect on the objects in time for those comparisons.

One specific use case for calling proxy methods ahead of type comparison would be to support comparing strings created using glue to ordinary strings - see tidyverse/glue#212 about the current situation testing glue output with testthat 3e and workarounds.

I'm not sure if this change is workable - if not then hopefully raising this issue and the linked one point people to the way to handle testing with glue output in testthat 3e. Thanks.