Access modifier of union ctors are configurable + implicit conversion…

…s can be omitted.

samples/Thinktecture.Runtime.Extensions.Samples/DiscriminatedUnions/TextOrNumberWithAdditionalProperty.cs

@@ -0,0 +1,22 @@
+namespace Thinktecture.DiscriminatedUnions;
+
+[Union<string, int>(T1Name = "Text",
+                    T2Name = "Number",
+                    SkipImplicitConversionFromValue = true,
+                    ConstructorAccessModifier = UnionConstructorAccessModifier.Private)]
+public sealed partial class TextOrNumberExtended
+{
+   public required string AdditionalProperty { get; init; }
+
+   public TextOrNumberExtended(string text, string additionalProperty)
+      : this(text)
+   {
+      AdditionalProperty = additionalProperty;
+   }
+
+   public TextOrNumberExtended(int number, string additionalProperty)
+      : this(number)
+   {
+      AdditionalProperty = additionalProperty;
+   }
+}

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/DiscriminatedUnions/AllEnumSettings.cs

@@ -7,13 +7,17 @@ public sealed class AllUnionSettings : IEquatable<AllUnionSettings>
    public SwitchMapMethodsGeneration MapMethods { get; }
    public IReadOnlyList<MemberTypeSetting> MemberTypeSettings { get; }
    public StringComparison DefaultStringComparison { get; }
+   public UnionConstructorAccessModifier ConstructorAccessModifier { get; }
+   public bool SkipImplicitConversionFromValue { get; }
 
    public AllUnionSettings(AttributeData attribute, int numberOfMemberTypes)
    {
       SkipToString = attribute.FindSkipToString() ?? false;
       SwitchMethods = attribute.FindSwitchMethods();
       MapMethods = attribute.FindMapMethods();
       DefaultStringComparison = attribute.FindDefaultStringComparison();
+      ConstructorAccessModifier = attribute.FindUnionConstructorAccessModifier();
+      SkipImplicitConversionFromValue = attribute.FindSkipImplicitConversionFromValue();
 
       var memberTypeSettings = new MemberTypeSetting[numberOfMemberTypes];
       MemberTypeSettings = memberTypeSettings;
@@ -41,6 +45,8 @@ public bool Equals(AllUnionSettings? other)
              && SwitchMethods == other.SwitchMethods
              && MapMethods == other.MapMethods
              && DefaultStringComparison == other.DefaultStringComparison
+             && ConstructorAccessModifier == other.ConstructorAccessModifier
+             && SkipImplicitConversionFromValue == other.SkipImplicitConversionFromValue
              && MemberTypeSettings.SequenceEqual(other.MemberTypeSettings);
    }
 
@@ -52,6 +58,8 @@ public override int GetHashCode()
          hashCode = (hashCode * 397) ^ SwitchMethods.GetHashCode();
          hashCode = (hashCode * 397) ^ MapMethods.GetHashCode();
          hashCode = (hashCode * 397) ^ (int)DefaultStringComparison;
+         hashCode = (hashCode * 397) ^ (int)ConstructorAccessModifier;
+         hashCode = (hashCode * 397) ^ SkipImplicitConversionFromValue.GetHashCode();
          hashCode = (hashCode * 397) ^ MemberTypeSettings.ComputeHashCode();
 
          return hashCode;

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/DiscriminatedUnions/UnionCodeGenerator.cs

@@ -97,7 +97,9 @@ private void GenerateUnion(CancellationToken cancellationToken)
             GenerateMap(true);
       }
 
-      GenerateImplicitConversions();
+      if (!_state.Settings.SkipImplicitConversionFromValue)
+         GenerateImplicitConversions();
+
       GenerateExplicitConversions();
       GenerateEqualityOperators();
       GenerateEquals();
@@ -702,7 +704,7 @@ private void GenerateConstructors()
       /// Initializes new instance with <paramref name=""").Append(memberType.ArgumentName.Raw).Append(@"""/>.
       /// </summary>
       /// <param name=""").Append(memberType.ArgumentName.Raw).Append(@""">Value to create a new instance for.</param>
-      public ").Append(_state.Name).Append("(").AppendTypeFullyQualified(memberType).Append(" ").Append(memberType.ArgumentName.Escaped).Append(@")
+      ").AppendAccessModifier(_state.Settings.ConstructorAccessModifier).Append(" ").Append(_state.Name).Append("(").AppendTypeFullyQualified(memberType).Append(" ").Append(memberType.ArgumentName.Escaped).Append(@")
       {
          this._").Append(memberType.ArgumentName.Raw).Append(" = ").Append(memberType.ArgumentName.Escaped).Append(@";
          this._valueIndex = ").Append(i + 1).Append(@";

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/DiscriminatedUnions/UnionSettings.cs

@@ -9,6 +9,8 @@ namespace Thinktecture.CodeAnalysis.DiscriminatedUnions;
    public SwitchMapMethodsGeneration SwitchMethods => _settings.SwitchMethods;
    public SwitchMapMethodsGeneration MapMethods => _settings.MapMethods;
    public StringComparison DefaultStringComparison => _settings.DefaultStringComparison;
+   public UnionConstructorAccessModifier ConstructorAccessModifier => _settings.ConstructorAccessModifier;
+   public bool SkipImplicitConversionFromValue => _settings.SkipImplicitConversionFromValue;
    public bool HasStructLayoutAttribute => _attributeInfo.HasStructLayoutAttribute;
 
    public UnionSettings(AllUnionSettings settings, AttributeInfo attributeInfo)
@@ -28,6 +30,8 @@ public bool Equals(UnionSettings other)
              && SwitchMethods == other.SwitchMethods
              && MapMethods == other.MapMethods
              && DefaultStringComparison == other.DefaultStringComparison
+             && ConstructorAccessModifier == other.ConstructorAccessModifier
+             && SkipImplicitConversionFromValue == other.SkipImplicitConversionFromValue
              && HasStructLayoutAttribute == other.HasStructLayoutAttribute;
    }
 
@@ -39,6 +43,8 @@ public override int GetHashCode()
          hashCode = (hashCode * 397) ^ SwitchMethods.GetHashCode();
          hashCode = (hashCode * 397) ^ MapMethods.GetHashCode();
          hashCode = (hashCode * 397) ^ (int)DefaultStringComparison;
+         hashCode = (hashCode * 397) ^ (int)ConstructorAccessModifier;
+         hashCode = (hashCode * 397) ^ SkipImplicitConversionFromValue.GetHashCode();
          hashCode = (hashCode * 397) ^ HasStructLayoutAttribute.GetHashCode();
 
          return hashCode;

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/UnionConstructorAccessModifier.cs

@@ -0,0 +1,8 @@
+namespace Thinktecture.CodeAnalysis;
+
+public enum UnionConstructorAccessModifier
+{
+   Private = 1 << 0,
+   Internal = 1 << 2,
+   Public = 1 << 3
+}

src/Thinktecture.Runtime.Extensions.SourceGenerator/Extensions/AttributeDataExtensions.cs

@@ -169,6 +169,17 @@ public static bool FindTxIsNullableReferenceType(this AttributeData attributeDat
       return GetStringParameterValue(attributeData, $"T{index}Name");
    }
 
+   public static UnionConstructorAccessModifier FindUnionConstructorAccessModifier(this AttributeData attributeData)
+   {
+      return (UnionConstructorAccessModifier?)GetIntegerParameterValue(attributeData, "ConstructorAccessModifier")
+             ?? UnionConstructorAccessModifier.Public;
+   }
+
+   public static bool FindSkipImplicitConversionFromValue(this AttributeData attributeData)
+   {
+      return GetBooleanParameterValue(attributeData, "SkipImplicitConversionFromValue") ?? false;
+   }
+
    public static (ITypeSymbol ComparerType, ITypeSymbol ItemType)? GetComparerTypes(this AttributeData attributeData)
    {
       if (attributeData.AttributeClass is not { } attributeClass || attributeClass.TypeKind == TypeKind.Error)

src/Thinktecture.Runtime.Extensions.SourceGenerator/Extensions/StringBuilderExtensions.cs

@@ -43,6 +43,26 @@ public static StringBuilder RenderAccessModifier(
       return sb;
    }
 
+   public static StringBuilder AppendAccessModifier(
+      this StringBuilder sb,
+      UnionConstructorAccessModifier accessModifier)
+   {
+      switch (accessModifier)
+      {
+         case UnionConstructorAccessModifier.Private:
+            sb.Append("private");
+            break;
+         case UnionConstructorAccessModifier.Internal:
+            sb.Append("internal");
+            break;
+         case UnionConstructorAccessModifier.Public:
+            sb.Append("public");
+            break;
+      }
+
+      return sb;
+   }
+
    public static StringBuilder RenderArguments(
       this StringBuilder sb,
       IReadOnlyList<InstanceMemberInfo> members,

src/Thinktecture.Runtime.Extensions/UnionAttributeBase.cs

@@ -16,6 +16,20 @@ public abstract class UnionAttributeBase : Attribute
    /// </summary>
    public bool SkipToString { get; set; }
 
+   /// <summary>
+   /// Defines the access modifier of the constructors.
+   /// Default is <see cref="UnionConstructorAccessModifier.Public"/>.
+   /// </summary>
+   /// <remarks>
+   /// Access modifier of the constructors will have effect on the access modifier of implicit casts.
+   /// </remarks>
+   public UnionConstructorAccessModifier ConstructorAccessModifier { get; set; } = UnionConstructorAccessModifier.Public;
+
+   /// <summary>
+   /// Indication whether the generator should skip the implementation of implicit conversions from value to union type.
+   /// </summary>
+   public bool SkipImplicitConversionFromValue { get; set; }
+
    /// <summary>
    /// Indication whether and how the generator should generate the methods <c>Switch</c>.
    /// </summary>

src/Thinktecture.Runtime.Extensions/UnionConstructorAccessModifier.cs

@@ -0,0 +1,22 @@
+namespace Thinktecture;
+
+/// <summary>
+/// Access modifer.
+/// </summary>
+public enum UnionConstructorAccessModifier
+{
+   /// <summary>
+   /// Access modifer "private".
+   /// </summary>
+   Private = 1 << 0,
+
+   /// <summary>
+   /// Access modifer "internal".
+   /// </summary>
+   Internal = 1 << 2,
+
+   /// <summary>
+   /// Access modifer "public".
+   /// </summary>
+   Public = 1 << 3
+}