Check why we avoid parameterizing indexer method parameters in the funcletizer

[roji]

We have the following code in ExpressionTreeFuncletizer:

private bool IsParameterParameterizable(MethodInfo method, ParameterInfo parameter)
    => parameter.GetCustomAttribute<NotParameterizedAttribute>() is null
        && !_model.IsIndexerMethod(method);

... which means that we constantize arguments to what we identify as indexers (also not sure why the model needs to be involved in determining that something is an indexer...).

For example, this prevents parameters from being parameterized when using the PostgreSQL hstore type, which maps to Dictionary<string, string> (see npgsql/efcore.pg#3285 (comment)).

[yinzara]

If this is the problem that's causing the issue with hstore, I'm curious, why is ImmutableDictionary not behaving the same way? They both are using an indexer property and it seems to be working correctly.

OOOOO you know what I'm betting it's because there is no set on an ImmutableDictionary's indexer property and for some reason that's making the difference.

[roji]

@yinzara I don't think it's the absence of a setter, but there's some difference there which makes the funcletizer identify one and not the other... You can debug into the code I referenced above to find out.