Dynamic (DLR) objects work in some places today, but not others. This change expands that support to ForEach-Object, Where-Object and the family of cmdlets that use 'MshExpression' (Select-Object, etc.).
This change addresses both wildcard and non-wildcard cases. In wildcard cases, it uses the existing support of generating PSDynamicMember objects for names returned by GetDynamicMemberNames.
In non-wildcard cases, a dynamic property access is attempted whether or not the name shows up in GetDynamicMemberNames, but a truly "blind" access is only attempted if we see that the base object is an IDMOP. If the dynamic access fails, you'll get the same or a similar error experience as before ("The property 'Blarg' cannot be found", or no error at all, depending on the cmdlet and the strict mode setting).
The included test coverage includes a stub for the.ForEach operator--once people are happy with this change, I can continue by adding support there.
This change should allegedly also have positive perf impact, though in actual perf testing, although it does seem ever-so-slightly faster, I found it difficult to measure much difference at all.
yotsuda