IMP: recognize type-mapped Bool variables as Bool variables

[colinvwood]

Description

Fixes an issue where type-mapped Bool variables were not recognized as Bools and rendering on the cli fell back to the standard --p-param VALUE format.

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AI Usage Details

Generated by Codex while working on qiime2/q2-dada2#190

[colinvwood]

Needed by qiime2/q2-dada2#190

[ebolyen]

I don't think you actually need this PR for what you wanted to do, but I have no objection to making it so that TypeVar where all branches are Bool is treated the same as Bool % TypeVar.

[colinvwood]

What's your preference re keeping this? Indeed your changes in q2-dada2 got me to the same place.

[ebolyen]

I think there's no harm in making this work. I guess the only difficulty is testing and if it's worth adding another action to dummy_plugin for it.

I'm also fine with putting it on the back-burner. There are perhaps other ways to handle this directly, such as distributing the TypeVar branches over the predicate so that it just always normalizes. Although it may be tricky to ensure that it still looks correct at different call-sites.