Context

Base issue: #11225
Reference package path: microsoft.bcl.asyncinterfaces
Roslyn-based GenAPI location: https://github.com/dotnet/sdk/tree/main/src/GenAPI/

Usage:

/repos/source-build-reference-packages]# ./generate.sh --pkg microsoft.extensions.logging,2.1.1 --genapi-backend roslyn --dest /repos/source-build-reference-packages/src/referencePackages/roslyn/

Steps:

1. Generate SBRP package using SBRP generator with the roslyn-based backend
2. Compare cci-based <-> roslyn-based reference assemblies
3. Build the SBRP generated with the roslyn-based backend
4. Collect issues, their occurrence, create bugs for each.
5. Run the sdk/ApiCompat tool to compare generated API with original

How to compile project in SBRP

Use a docker or a VM and from root folder of source-build-reference-packages run:

/repos/source-build-reference-packages]# ./build.sh --projects ./build.sh --projects /repos/source-build-reference-packages/src/referencePackages/roslyn/system.memory/4.5.1/System.Memory.4.5.1.csproj

How to use the ApiCompat tool

sdk\artifacts\bin\Microsoft.DotNet.ApiCompat.Tool\Debug\net6.0> .\Microsoft.DotNet.ApiCompat.Tool.exe --strict-mode true --enable-rule-attributes-must-match true --enable-rule-cannot-change-parameter-name true --lref ... --rref ... -l ... -r ...

Found Issues:

• The SyntaxGenerator does not generate this and params keywords in methods #11853

Occurrence: 3

• The SyntaxGenerator class does not generate default values for parameters of methods/constructors. #11734

Occurrence: 1

• The SyntaxGenerator omits in, out keywords for generic types #11884

Occurrence: 2
/!? Does not affect compilation

- public partial interface IAsyncEnumerable<T>
+ public partial interface IAsyncEnumerable<out T>
{
}

• For a compile-time compat add synthesized private fields for a value type (struct) #11347

Occurrence: 2

• Generate a call of a base class constructor if the default constructor does not exist. #11254

Occurrence: 1

[System.AttributeUsageAttribute(System.AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
public sealed partial class AsyncIteratorStateMachineAttribute : System.Runtime.CompilerServices.StateMachineAttribute
{
    // error CS7036: There is no argument given that corresponds to the required formal parameter 'stateMachineType' of 'StateMachineAttribute.StateMachineAttribute(Type)'
    // Must be something like: public AsyncIteratorStateMachineAttribute(System.Type stateMachineType) : base(stateMachineType) {}
    public AsyncIteratorStateMachineAttribute(System.Type stateMachineType) { throw null; }
}

• The DeclarationModifiers class does not properly handle readonly keyword for struct \s #11850

Occurrence: 3
/!? Does not affect compilation