Fix unit tests for generators

These two generators should never cause a build error

Author: Sergio0694

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservableValidatorValidateAllPropertiesGenerator.cs

@@ -9,7 +9,6 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;
 
@@ -40,8 +39,6 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             .Select(static (item, _) => Execute.GetInfo(item))
             .WithComparer(ValidationInfo.Comparer.Default);
 
-        context.FilterWithLanguageVersion(ref validationInfo, LanguageVersion.CSharp8, UnsupportedCSharpLanguageVersionError);
-
         // Check whether the header file is needed
         IncrementalValueProvider<bool> isHeaderFileNeeded =
             validationInfo

CommunityToolkit.Mvvm.SourceGenerators/Messaging/IMessengerRegisterAllGenerator.cs

@@ -10,7 +10,6 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;
 
@@ -48,8 +47,6 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             .Select(static (item, _) => Execute.GetInfo(item.Type, item.Interfaces))
             .WithComparer(RecipientInfo.Comparer.Default);
 
-        context.FilterWithLanguageVersion(ref recipientInfo, LanguageVersion.CSharp8, UnsupportedCSharpLanguageVersionError);
-
         // Check whether the header file is needed
         IncrementalValueProvider<bool> isHeaderFileNeeded =
             recipientInfo

tests/CommunityToolkit.Mvvm.SourceGenerators.UnitTests/Test_SourceGeneratorsDiagnostics.cs

@@ -296,6 +296,7 @@ public partial class SampleViewModel
     }
 
     [TestMethod]
+    [Ignore("The generator should just not trigger at all in this scenario, update this after migrating diagnostics")]
     public void UnsupportedCSharpLanguageVersion_FromObservableValidatorValidateAllPropertiesGenerator()
     {
         string source = @"
@@ -311,9 +312,9 @@ public partial class SampleViewModel : ObservableValidator
                 }
             }";
 
+        // Compilation should be fine on C# 7.3 as well (the generator just doesn't trigger)
         VerifyGeneratedDiagnostics<ObservableValidatorValidateAllPropertiesGenerator>(
-            CSharpSyntaxTree.ParseText(source, CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.CSharp7_3)),
-            "MVVMTK0008");
+            CSharpSyntaxTree.ParseText(source, CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.CSharp7_3)));
 
         VerifySuccessfulGeneration(source);
     }
@@ -362,9 +363,10 @@ public void Receive(MyMessage message)
                 }
             }";
 
+        // This should run fine on C# 8.0 too, as it doesn't use any newer features. Additionally, when not supported this
+        // generator should just not run, not cause issues. The MVVM Toolkit has a reflection-based fallback path for this.
         VerifyGeneratedDiagnostics<IMessengerRegisterAllGenerator>(
-            CSharpSyntaxTree.ParseText(source, CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.CSharp7_3)),
-            "MVVMTK0008");
+            CSharpSyntaxTree.ParseText(source, CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.CSharp8)));
 
         VerifySuccessfulGeneration(source);
     }
@@ -1496,11 +1498,11 @@ private static void VerifyGeneratedDiagnostics<TGenerator>(SyntaxTree syntaxTree
     }
 
     /// <summary>
-    /// Verifies the output of a source generator.
+    /// Verifies the output of one or more source generators.
     /// </summary>
-    /// <typeparam name="TGenerator">The generator type to use.</typeparam>
     /// <param name="syntaxTree">The input source tree to process.</param>
-    /// <param name="diagnosticsIds">The diagnostic ids to expect for the input source code.</param>
+    /// <param name="generators">The generators to apply to the input syntax tree.</param>
+    /// <param name="generatorDiagnosticsIds">The diagnostic ids to expect for the input source code.</param>
     private static void VerifyGeneratedDiagnostics(SyntaxTree syntaxTree, IIncrementalGenerator[] generators, string[] generatorDiagnosticsIds)
     {
         Type observableObjectType = typeof(ObservableObject);