Support mapping object factory parameters

[skuirrels]

Support mapping object factory parameters

Description

Adds ObjectFactoryAttribute.MapToParameters so object factory method parameters can be mapped from source members using the same matching rules as constructor mappings.

This enables object factories such as:

[ObjectFactory(MapToParameters = true)]
private CarDto CreateCarDto(string make, string model)
    => CarDto.Create(make, model);

The PR includes:

• Support for direct parameter-mapped object factories.
• Support for generic factory shapes, including target-generic and source/target-generic factory methods.
• Fallback behavior aligned with constructor candidate selection: unmappable parameter factories fall through to the next object factory or constructor.
• Projection/expression handling that avoids using parameter-mapped factories where they cannot be represented safely.
• Documentation for MapToParameters and supported factory signatures.
• Unit coverage for direct, optional-parameter, generic, fallback, and projection/expression cases.

Related issue: none. This PR was opened before the requested issue-first design discussion; I am happy to move the design discussion to an issue if preferred.

Checklist

• I did not use AI tools to generate this PR, or I have manually verified that the code is correct, optimal, and follows the project guidelines and architecture
• I understand that low-quality, AI-generated PRs will be closed immediately without further explanation
• The existing code style is followed
• The commit message follows our guidelines
• Performed a self-review of my code
• Hard-to-understand areas of my code are commented
• The documentation is updated (as applicable)
• Unit tests are added/updated
• Integration tests are added/updated (as applicable, especially if feature/bug depends on roslyn or framework version in use)

Validation performed:

• dotnet test test/Riok.Mapperly.Tests/Riok.Mapperly.Tests.csproj --filter "FullyQualifiedName~ObjectFactoryTest|FullyQualifiedName~ExpressionMappingTest"
• dotnet test Riok.Mapperly.slnx --no-restore -m:1 --blame-crash --results-directory artifacts/TestResults/final-verification
  • Abstractions: 6 passed
  • Integration: 77 passed
  • Main tests: 1629 passed, 2 skipped

[latonz]

Thanks for the contribution. Before we review this further, please update the PR description to use the repository’s PR template.

Also, for larger feature PRs like this, please open an issue first so the scope and intended design can be discussed before implementation.

[skuirrels]

Thanks for the contribution. Before we review this further, please update the PR description to use the repository’s PR template.

Also, for larger feature PRs like this, please open an issue first so the scope and intended design can be discussed before implementation.

Hello. I updated the PR as per your template. I did raise this previously and this design was your recomendation to me.

[latonz]

The PR description still looks VERY AI generated…

Related issue: none. This PR was opened before the requested issue-first design discussion; I am happy to move the design discussion to an issue if preferred.

then

[…] I did raise this previously […]

Where did you raise it previously? Please link it.