Comparisons within `assign`

It appears that the assign operator doesn't like comparisons (i.e. [thing] contains [other thing]). For instance, I would expect this to work:

{%- assign is_some_product = variant.tags contains "example" -%}

But produces the error: Expected end_of_string but found comparison in [...]

I've used the following as a workaround:

{% if variant.tags contains "example" %}
  {%- assign is_some_product = true -%}
{% else %}
  {%- assign is_some_product = false -%}
{% endif %}

While the latter works, the former is much more concise and is what I would expect to work. Note that I found this while trying to use the or operator as well, but seeing as comparisons themselves aren't accepted, I don't think the parser even got that far.

edit 10/30/2020: The following snippet also works and is a bit more compact:

{%- assign is_some_product = false -%}
{% if variant.tags contains "example" %}
  {%- assign is_some_product = true -%}
{% endif %}

The issue identifies the assign operator and comparison syntax as the entry points, but names no files or tests. Start by locating the parser for assign expressions and the existing comparison handling, then reproduce the supplied snippets and add coverage showing that a comparison can be assigned successfully.