Unions2

Janus.Analyzers/Components/ConstructorComponent.cs

@@ -35,6 +35,10 @@ public void AppendTo(CSharpSourceBuilder builder, CancellationToken cancellation
                           {
                               var isValid = true;
                               Validate(value, throwIfInvalid: true, ref isValid);
+                              if(!isValid)
+                              {
+                                  throw new {{typeof(ArgumentException)}}($"{nameof(value)} was invalid.", nameof(value));
+                              }
                           }
 
                           {{Create(variant, static (v, b, ct) =>

Janus.Analyzers/Components/FactoriesComponent.cs

@@ -197,6 +197,28 @@ public static bool TryCreate(
                           {{variant.Type.NullableName}} value)
                           => new {{new UnionTypeNameComponent(m)}}(value, validate: true);
 
+                      {{Summary(m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append($"Creates an instance of {Cref(m.DocsCommentId)}.");
+                      })}}
+                      {{Param("value", m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append($"The value to create an instance of {Cref(m.DocsCommentId)} from.");
+                      })}}
+                      {{Returns(m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append($"The new instance of {Cref(m.DocsCommentId)}.");
+                      })}}
+                      public static {{new UnionTypeNameComponent(m)}} CreateFrom{{variant.Name}}(
+                          {{variant.Type.NullableName}} value)
+                          => new {{new UnionTypeNameComponent(m)}}(value, validate: true);
+
                       {{Summary(m, static (m, b, ct) =>
                       {
                           ct.ThrowIfCancellationRequested();
@@ -238,6 +260,48 @@ public static bool TryCreate(
 
                           return isValid;
                       }
+
+                      {{Summary(m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append($"Attempts to create an instance of {Cref(m.DocsCommentId)}.");
+                      })}}
+                      {{Param("value", m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append($"The value to create an instance of {Cref(m.DocsCommentId)} from.");
+                      })}}
+                      {{Param("union", m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append(
+                              $"""
+                               The instance of {Cref(m.DocsCommentId)} if one could be created; otherwise, 
+                               {(m.TypeKind is UnionTypeKind.Class ? Langword("null") : Langword("default"))}.
+                               """);
+                      })}}
+                      {{Returns(m, static (m, b, ct) =>
+                      {
+                          ct.ThrowIfCancellationRequested();
+
+                          b.Append($"{Langword("true")} if an instance of {Cref(m.DocsCommentId)} could be created; otherwise, {Langword("false")}.");
+                      })}}
+                      public static bool TryCreateFrom{{variant.Name}}(
+                          {{variant.Type.NullableName}} value,
+                          [{{typeof(NotNullWhenAttribute)}}(true)]
+                          out {{new UnionTypeNameComponent(m, RenderNullable: true)}} union)
+                      {
+                          var isValid = true;
+                          Validate(value, throwIfInvalid: false, ref isValid);
+                          union = isValid 
+                              ? new {{new UnionTypeNameComponent(m)}}(value, validate: false) 
+                              : default;
+
+                          return isValid;
+                      }
                       """
                 );
             }

Janus.Analyzers/Components/ToStringComponent.cs

@@ -57,7 +57,7 @@ public override string ToString()
 
                                      b.Append(
                                          $$"""
-                                           {{p}}{(typeof({{p}}).IsGenericTypeParameter ? string.Empty : $":{typeof({{p}})}" )}
+                                           {{p}}{(typeof({{p}}) is { IsGenericParameter: true, DeclaringMethod: null } ? string.Empty : $":{typeof({{p}})}" )}
                                            """
                                      );
                                  }, separator: ", ")}>");

Janus.Analyzers/UnionTypeSettingsAttribute.cs

@@ -105,14 +105,14 @@ sealed partial class UnionTypeSettingsAttribute : global::System.Attribute
         /// Defines how to generate an implementation for <see cref="Object.ToString"/>.
         /// </summary>
         public ToStringSetting ToStringSetting { get; set; }
+
         /// <summary>
         /// Indicates how to generate equality operators.
         /// By default, equality operators will only be emitted for value types, to preserve
         /// reference equality for comparing reference union types via <c>==</c> or <c>!=</c>.
         /// </summary>
         public EqualityOperatorsSetting EqualityOperatorsSetting { get; set; }
 
-
         /// <summary>
         /// Gets or sets a value indicating whether to make the union type JSON serializable.
         /// </summary>