Added diagnostic for failure in ObservablePropertyGenerator

Author: Sergio0694

Microsoft.Toolkit.Mvvm.SourceGenerators/AnalyzerReleases.Unshipped.md

@@ -13,4 +13,5 @@ MVVMTK0005 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableObjectGenerator |
 MVVMTK0006 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableObjectGenerator | Error | See https://aka.ms/mvvmtoolkit
 MVVMTK0007 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableRecipientGenerator | Error | See https://aka.ms/mvvmtoolkit
 MVVMTK0008 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableRecipientGenerator | Error | See https://aka.ms/mvvmtoolkit
-MVVMTK0009 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit
+MVVMTK0009 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit
+MVVMTK0010 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit

Microsoft.Toolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.cs

@@ -47,7 +47,14 @@ public void Execute(GeneratorExecutionContext context)
                 if (items.Key.DeclaringSyntaxReferences.Length > 0 &&
                     items.Key.DeclaringSyntaxReferences.First().GetSyntax() is ClassDeclarationSyntax classDeclaration)
                 {
-                    OnExecute(context, classDeclaration, items.Key, items);
+                    try
+                    {
+                        OnExecute(context, classDeclaration, items.Key, items);
+                    }
+                    catch
+                    {
+                        context.ReportDiagnostic(ObservablePropertyGeneratorError, items.Key, items.Key);
+                    }
                 }
             }
         }

Microsoft.Toolkit.Mvvm.SourceGenerators/Diagnostics/DiagnosticDescriptors.cs

@@ -156,5 +156,21 @@ internal static class DiagnosticDescriptors
             isEnabledByDefault: true,
             description: $"Cannot apply [{nameof(ObservablePropertyAttribute)}] to fields with validation attributes if they are declared in a type that doesn't inherit from ObservableValidator.",
             helpLinkUri: "https://aka.ms/mvvmtoolkit");
+
+        /// <summary>
+        /// Gets a <see cref="DiagnosticDescriptor"/> indicating when <see cref="ObservablePropertyGenerator"/> failed to run on a given type.
+        /// <para>
+        /// Format: <c>"The generator ObservablePropertyGenerator failed to execute on type {0}"</c>.
+        /// </para>
+        /// </summary>
+        public static readonly DiagnosticDescriptor ObservablePropertyGeneratorError = new(
+            id: "MVVMTK0010",
+            title: $"Internal error for {nameof(ObservablePropertyGenerator)}",
+            messageFormat: $"The generator {nameof(ObservablePropertyGenerator)} failed to execute on type {{0}}",
+            category: typeof(ObservableObjectGenerator).FullName,
+            defaultSeverity: DiagnosticSeverity.Error,
+            isEnabledByDefault: true,
+            description: $"The {nameof(ObservablePropertyGenerator)} generator encountered an error while processing a type. Please report this issue at https://aka.ms/mvvmtoolkit.",
+            helpLinkUri: "https://aka.ms/mvvmtoolkit");
     }
 }