InvalidCastException when mapping IReadOnlyDictionary<int, int> to the same type

Source/destination types

public class Source
{
    public IReadOnlyDictionary<int, int> Values { get; set; }
}

public class Destination
{
    public IReadOnlyDictionary<int, int> Values { get; set; }
}

Mapping configuration

    var mapper = new MapperConfiguration(config =>
    {
        config.CreateMap<Source, Destination>();
    }).CreateMapper();

Version: 7.0.1

Expected behavior

Should successfully map Source.Values to Destination.Values.

Actual behavior

Throws AutoMapperMappingException:

Error mapping types.

Mapping types: Source -> Destination UserQuery+Source -> UserQuery+Destination

Type Map configuration: Source -> Destination UserQuery+Source -> UserQuery+Destination

Property: Values

(UserQuery is the root class in a LINQPad query)

Inner exception: InvalidCastException:

Unable to cast object of type ‘System.Collections.Generic.List1[System.Collections.Generic.KeyValuePair2[System.Int32,System.Int32]]’ to type ‘System.Collections.Generic.IReadOnlyDictionary`2[System.Int32,System.Int32]’.

Steps to reproduce

    var source = new Source
    {
        Values = new Dictionary<int, int> { [1] = 42 }
    };
    
    var destination = mapper.Map<Destination>(source);

[jbogard]

I’m gonna add a new issue for this one, for tracking purposes.

[lbargaoanu]

I doubt it. If you’ll give it some thought it should be easy to do.