Dapper constructor source generator

DapperConstructorSourceGenerator.cs

global using Microsoft.CodeAnalysis;
global using Microsoft.CodeAnalysis.CSharp.Syntax;
using System.Diagnostics;

namespace Srcgen;


/// <summary>
/// Author: Saahil Claypool
/// https://github.com/dotnet/roslyn/blob/main/docs/features/incremental-generators.md
/// </summary>
[Generator]
public class DapperConstructorGenerator : IIncrementalGenerator
{
    public const string AttributeNameSpace = "Srcgen";
    public const string AttributeName = "DapperConstructorAttribute";
    public const string AttributeFullName = "Srcgen.DapperConstructorAttribute";

    public void Initialize(IncrementalGeneratorInitializationContext context)
    {
        var generatorAttributes = context.SyntaxProvider.ForAttributeWithMetadataName(
                AttributeFullName,
                (_, _) => true,
                (syntaxContext, _) => syntaxContext
            ).Combine(context.CompilationProvider);


        context.RegisterSourceOutput(generatorAttributes, (sourceProductionContext, tuple) =>
        {
            var (generatorActivationContext, compilation) = tuple;

            if (generatorActivationContext.TargetSymbol is not INamedTypeSymbol symbol)
                return;

            var constructor = symbol.Constructors.First();
            var parameters = constructor.Parameters.Select(p => (Type: $"{p.Type.ContainingNamespace}.{p.Type.Name}", p.Name));
            var defaultsString = string.Join(", ", parameters.Select(p => "default!"));
            var source = $$"""
                namespace {{symbol.ContainingNamespace}}
                {
                    public partial record {{symbol.Name}}
                    {
                        private {{symbol.Name}}() : this({{defaultsString}}) { }
                    }
                }
                """;
            // Avoid duplicate names
            sourceProductionContext.AddSource(
                $"{symbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat.WithGlobalNamespaceStyle(SymbolDisplayGlobalNamespaceStyle.Omitted))}_{AttributeFullName}.g.cs",
                source);
        });
        context.RegisterPostInitializationOutput(callback: ctx =>
        {
            ctx.AddSource(
                $"{AttributeFullName}.g.cs",
                $$"""
                namespace {{AttributeNameSpace}}
                {
                    /// <summary>
                    /// generate a constructor with all parameters set to default
                    /// this is only to be used by dapper or other serializers that require
                    /// a no parameter constructor.
                    /// </summary>
                    [System.AttributeUsage(System.AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
                    sealed class {{AttributeName}} : System.Attribute
                    {
                        public {{AttributeName}}() { }
                    }
                }
                """
            );
        });
    }
}

Sample.cs

[Srcgen.DapperConstructor]
public partial record TestMe(string A, string B)
{
    public int C { get; set; }
}

/* generated

namespace Tasks
{
    public partial record TestResult
    {
        private TestResult() : this(default!, default!) { }
    }
}
*/

Srcgen.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <EnforceExtendedAnalyzerRules>true</EnforceExtendedAnalyzerRules>
    <LangVersion>preview</LangVersion>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" />
  </ItemGroup>

</Project>

Hi,
I tried to use it but I have the error "DapperConstructor" and "DapperConstructorAttribute" doesn't exist
I tried with only your generator + sample to test