Make source generated JsonTypeInfo properties nullable-oblivious

src/libraries/System.Text.Json/gen/JsonSourceGenerator.Emitter.cs

@@ -3,12 +3,10 @@
 
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Globalization;
 using System.Linq;
 using System.Reflection;
 using System.Text.Json.Serialization;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Text;
 using SourceGenerators;
 
@@ -1009,7 +1007,9 @@ private static void GenerateTypeInfoFactoryHeader(SourceWriter writer, TypeGener
  /// <summary>
  /// Defines the source generated JSON serialization contract metadata for a given type.
  /// </summary>
+ #nullable disable annotations // Marking the property type as nullable-oblivious.
  public {{typeInfoFQN}} {{typeInfoPropertyName}}
+ #nullable enable annotations
  {
  get => _{{typeInfoPropertyName}} ??= ({{typeInfoFQN}}){{OptionsInstanceVariableName}}.GetTypeInfo(typeof({{typeFQN}}));
  }

src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs

@@ -737,5 +737,36 @@ public class MyClass
  Compilation compilation = CompilationHelper.CreateCompilation(source, parseOptions: CompilationHelper.CreateParseOptions(languageVersion));
  CompilationHelper.RunJsonSourceGenerator(compilation);
  }
+
+ [Fact]
+ public void DoesNotWarnOnNullabilityMismatch()
+ {
+ string source = $$"""
+ using System.Collections.Generic;
+ using System.Text.Json;
+ using System.Text.Json.Serialization;
+ #nullable enable
+
+ namespace HelloWorld
+ {
+ public static class MyClass
+ {
+ public static string Test()
+ {
+ Dictionary<int, string?> values = new();
+ return JsonSerializer.Serialize(values, JsonContext.Default.DictionaryInt32String);
+ }
+ }
+
+ [JsonSerializable(typeof(Dictionary<int, string>))]
+ internal partial class JsonContext : JsonSerializerContext
+ {
+ }
+ }
+ """;
+
+ Compilation compilation = CompilationHelper.CreateCompilation(source);
+ CompilationHelper.RunJsonSourceGenerator(compilation);
+ }
  }
 }