Background and motivation

If I write assertion this way:

 actualEnv.Should().BeEquivalentTo(env, _ => _.Excluding(_ => new { _.Id, _.Creator, _.LastEditor }));

the exception is thrown:

System.ArgumentException : Expression <new <>f__AnonymousType0`3(Id = _.Id, Creator = _.Creator, LastEditor = _.LastEditor)> cannot be used to select a member. (Parameter 'expression')

So I have to write it slightly more verbose.

 actualEnv.Should().BeEquivalentTo(env, _ => _.Excluding(_ => _.Id).Excluding(_ => _.Creator).Excluding(_ => _.LastEditor));

API Proposal

So, my proposal is to treat expression for anonymous object creation as an enumeration of properties to exclude.
For example EF Core uses this approach for defining composite key.

API Usage

a.Shoul().BeEquivalentTo(b, _ => _.Excluding(b => new { b.Prop1, ...., b.PropN }));

Alternative Designs

No response

Risks

No response

Are you willing to help with a proof-of-concept (as PR in that or a separate repo) first and as pull-request later on?

No