Duplicate Mappings of generics throwing an exception

[tiasmt]

Mapping configuration

protected override MapperConfiguration CreateConfiguration() => new(cfg =>
    {
        cfg.CreateMap(typeof (Source<>), typeof (Dest<>));
        cfg.CreateMap(typeof (Source<>), typeof (Dest<>));
    });

Version: 12.0.1

Expected behavior

Maps are created and when calling mapperConfiguration.AssertConfigurationIsValid(); an error is thrown. (Same as when adding duplicate mappings of non open generics)

Actual behavior

Maps are not created and a duplicate key exception is thrown.

Steps to reproduce

Run the GenericsTests changing the Create Configuration as per above snippet

[lbargaoanu]

I don't know. It seems easier to debug things when the error is thrown where the problem is. What's the point of throwing later, how is that better? You'd have to go back and find the mapping in question.