Allow translating non-constant NewExpression in translators and plugins

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp

Research direction

Start with the NodaTime expression shown in the issue and trace how NewExpression nodes with non-evaluatable constructor arguments reach translators and plugins. Compare this with the SQL translating visitor path mentioned for DateTime. Done means such constructors can be translated through a translator and the capability is exposed to plugins without relying on constant evaluation.

Written by the indexing model from the issue text.

Description

area-query needs-design

We currently can't translate the following NodaTime expression:

var d = ctx.NodaTimeTypes.Single(t => t.LocalDate < new LocalDate(t.LocalDate.Year, 4, 21));

... since the constructor contains a non-evaluatable parameter. Ideally it should be possible to translate via a translator (like method or member), and exposed to plugins as well.

Low priority, at the moment am only aware of NodaTime types - but there may be others. Raised in https://github.com/npgsql/efcore.pg/issues/1020.

Note that for DateTime this can be done in the SQL translating visitor, as it isn't a plugin.

Dominant language
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