Fix .NET variant warnings and unused model imports

GUIDE.md

@@ -1723,8 +1723,9 @@ Cannot be combined with `@nexus.source`.
 Adds an experimental API warning to the generated declaration's documentation.
 The directive takes no arguments. Mark declarations individually; marking an
 interface does not implicitly mark its types. For variants, the warning belongs
-to the variant declaration, not its individual cases, in Python, TypeScript, Go,
-and .NET.
+to the variant declaration, not its individual cases, in Python, TypeScript, and
+Go. In .NET, the warning appears on both the variant's base record and each
+nested case record.
 
 ```wit
 /// @nexus.experimental

advanced/samples/dotnet/wit/notification-service/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 
 namespace Nexgen.NotificationService
 {
@@ -22,12 +21,14 @@ private OnCompleteRequestResult() { }
         /// <summary>
         /// The source operation completed successfully with this output.
         /// </summary>
+        /// <remarks>WARNING: This API is experimental and may change in the future.</remarks>
         [GeneratedCode("nexgen", null)]
         public sealed record Success(TOutput Value) : OnCompleteRequestResult<TOutput>;
 
         /// <summary>
         /// The source operation failed, including timeout, cancellation, and application errors.
         /// </summary>
+        /// <remarks>WARNING: This API is experimental and may change in the future.</remarks>
         [GeneratedCode("nexgen", null)]
         public sealed record Failure(System.Exception Value) : OnCompleteRequestResult<TOutput>;
     }

advanced/samples/dotnet/wit/proto-generic/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 using Nexgen.Support;
 
 namespace Nexgen.ProtoGeneric

advanced/samples/dotnet/wit/proto-oneof/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 using Nexgen.Support;
 
 namespace Nexgen.ProtoOneof

advanced/samples/dotnet/wit/start-workflow/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 using Nexgen.Support;
 
 namespace Nexgen.StartWorkflowService

advanced/samples/dotnet/wit/stream-service/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 using Nexgen.Support;
 
 namespace Nexgen.StreamService

advanced/samples/dotnet/wit/type-roundtrip/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 using Nexgen.Support;
 
 namespace Nexgen.TypeRoundtripService

advanced/samples/dotnet/wit/workflow-service/Models.cs

@@ -5,7 +5,6 @@
 using System;
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
-using Temporalio.Converters;
 using Nexgen.Support;
 
 namespace Temporalio.Workflows

changelog/fixed/warning-wearing-waffle.md

@@ -0,0 +1 @@
+The .NET generator now includes experimental API remarks on nested cases of experimental variants and omits the unused `Temporalio.Converters` import from model files.

src/generator/dotnet.rs

@@ -85,13 +85,6 @@ impl<'a> ApiPlanner<'a> {
             "System.CodeDom.Compiler",
             "System.Collections.Generic",
         ];
-        if models.iter().any(|model| {
-            self.external_models
-                .model_transfer_converter_attribute(model, self.api_plan)
-                .is_some()
-        }) {
-            imports.push("Temporalio.Converters");
-        }
         if self.external_model_fragments.has_models() {
             imports.push("System.Text.Json");
             imports.push("System.Text.Json.Serialization");
@@ -590,7 +583,7 @@ impl<'a> ApiPlanner<'a> {
         output.push_str("() { }\n\n");
         for (index, case) in variant.cases.iter().enumerate() {
             let case_name = csharp_type_name(&case.name);
-            render_xml_summary(output, "    ", case.doc.value(), false);
+            render_xml_summary(output, "    ", case.doc.value(), variant.experimental);
             output.push_str("    ");
             output.push_str(GENERATED_CODE_ATTRIBUTE);
             output.push('\n');

tests/generate_dotnet.rs

@@ -190,7 +190,7 @@ interface api {
 }
 
 #[test]
-fn dotnet_experimental_variant_warning_applies_only_to_base_records() {
+fn dotnet_experimental_variant_warning_applies_to_base_and_case_records() {
     let temp_dir = unique_output_path("dotnet-experimental-variants");
     fs::create_dir_all(&temp_dir).unwrap();
     let wit_path = temp_dir.join("variants.wit");
@@ -238,12 +238,19 @@ interface api {
     assert!(rendered.contains(&format!(
         "{WARNING}\n[GeneratedCode(\"nexgen\", null)]\npublic abstract record Undocumented"
     )));
+    assert!(rendered.contains(&format!(
+        "    /// <summary>\n    /// Documented case.\n    /// </summary>\n    {WARNING}\n    [GeneratedCode(\"nexgen\", null)]\n    public sealed record First("
+    )));
+    assert!(rendered.contains(&format!(
+        "    {WARNING}\n    [GeneratedCode(\"nexgen\", null)]\n    public sealed record Second : Undocumented;"
+    )));
+    assert!(
+        rendered.contains("\n[GeneratedCode(\"nexgen\", null)]\npublic abstract record Stable")
+    );
     assert!(rendered.contains(
-        "    /// <summary>\n    /// Documented case.\n    /// </summary>\n    [GeneratedCode(\"nexgen\", null)]\n    public sealed record First("
+        "\n    [GeneratedCode(\"nexgen\", null)]\n    public sealed record Third : Stable;"
     ));
-    assert!(rendered.contains("public sealed record Second : Undocumented;"));
-    assert!(rendered.contains("public abstract record Stable"));
-    assert_eq!(rendered.matches(WARNING).count(), 2);
+    assert_eq!(rendered.matches(WARNING).count(), 4);
     fs::remove_dir_all(temp_dir).unwrap();
 }
 
@@ -645,6 +652,24 @@ interface workflow-service {
     fs::remove_dir_all(temp_dir).unwrap();
 }
 
+#[test]
+fn dotnet_imports_converters_only_where_unqualified_types_need_them() {
+    let root = project_root();
+    for example in ["notification-service", "proto-oneof", "workflow-service"] {
+        let files = generate_dotnet_files(
+            &example_input_paths(&root, example),
+            &[descriptor_path(&root)],
+        );
+        let models = &files[&PathBuf::from("Models.cs")];
+        assert!(models.contains("Temporalio.Converters.TemporalTransferTypeConverter"));
+        assert!(!models.contains("using Temporalio.Converters;"));
+        if let Some(services) = files.get(&PathBuf::from("Services.cs")) {
+            assert!(services.contains("ISerializationContext"));
+            assert!(services.contains("using Temporalio.Converters;"));
+        }
+    }
+}
+
 #[test]
 fn dotnet_notification_models_convert_generic_oneofs_without_service() {
     let root = project_root();
@@ -658,15 +683,16 @@ fn dotnet_notification_models_convert_generic_oneofs_without_service() {
 
     assert!(!files.contains_key(&PathBuf::from("Services.cs")));
     assert!(!files.contains_key(&PathBuf::from("Operations.cs")));
+    assert!(!models.contains("using Temporalio.Converters;"));
     assert!(models.contains("namespace Nexgen.NotificationService\n{"));
     assert!(models.contains(
         "    /// <summary>\n    /// The successful output or failure of the source operation.\n    /// </summary>\n    /// <remarks>WARNING: This API is experimental and may change in the future.</remarks>\n    [GeneratedCode(\"nexgen\", null)]\n    public abstract record OnCompleteRequestResult<TOutput>"
     ));
     assert!(models.contains(
-        "        /// <summary>\n        /// The source operation completed successfully with this output.\n        /// </summary>\n        [GeneratedCode(\"nexgen\", null)]\n        public sealed record Success(TOutput Value)"
+        "        /// <summary>\n        /// The source operation completed successfully with this output.\n        /// </summary>\n        /// <remarks>WARNING: This API is experimental and may change in the future.</remarks>\n        [GeneratedCode(\"nexgen\", null)]\n        public sealed record Success(TOutput Value)"
     ));
     assert!(models.contains(
-        "        /// <summary>\n        /// The source operation failed, including timeout, cancellation, and application errors.\n        /// </summary>\n        [GeneratedCode(\"nexgen\", null)]\n        public sealed record Failure(System.Exception Value)"
+        "        /// <summary>\n        /// The source operation failed, including timeout, cancellation, and application errors.\n        /// </summary>\n        /// <remarks>WARNING: This API is experimental and may change in the future.</remarks>\n        [GeneratedCode(\"nexgen\", null)]\n        public sealed record Failure(System.Exception Value)"
     ));
     assert!(
         models.contains("    /// A notification that reports that a source operation completed.")