System.Text.Json emits uncompilable code

[SteveDunn]

Fix for #103515

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[stephentoub]

Should

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

Line 841 in 308d857

writer.WriteLine($"if ({propValueExpr} != null)");

change to is not as well?

[eiriktsarpalis]

Thanks. Would it be possible to a couple of regression tests for the change as well? The relevant test suite can be found here:

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

Lines 576 to 597 in 193b826

	[Fact]
	public static void NoErrorsWhenUsingIgnoredReservedCSharpKeywords()
	{
	string source = """
	using System.Text.Json.Serialization;
	namespace Test
	{
	[JsonSerializable(typeof(ClassWithPropertyNameThatIsAReservedKeyword))]
	public partial class JsonContext : JsonSerializerContext { }
	public class ClassWithPropertyNameThatIsAReservedKeyword
	{
	[JsonIgnore]
	public string @event { get; set; }
	}
	}
	""";
	Compilation compilation = CompilationHelper.CreateCompilation(source);
	CompilationHelper.RunJsonSourceGenerator(compilation);
	}

[eiriktsarpalis]

Thanks