Add Compilation.TryBuildNamedTypeSymbolMap extension

Author: Sergio0694

src/CommunityToolkit.Mvvm.SourceGenerators/Extensions/CompilationExtensions.cs

@@ -2,6 +2,10 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 
@@ -87,4 +91,37 @@ public static bool HasAccessibleTypeWithMetadataName(this Compilation compilatio
 
         return false;
     }
+
+    /// <summary>
+    /// Tries to build a map of <see cref="INamedTypeSymbol"/> instances form the input mapping of names.
+    /// </summary>
+    /// <typeparam name="T">The type of keys for each symbol.</typeparam>
+    /// <param name="compilation">The <see cref="Compilation"/> to consider for analysis.</param>
+    /// <param name="typeNames">The input mapping of <typeparamref name="T"/> keys to fully qualified type names.</param>
+    /// <param name="typeSymbols">The resulting mapping of <typeparamref name="T"/> keys to resolved <see cref="INamedTypeSymbol"/> instances.</param>
+    /// <returns>Whether all requested <see cref="INamedTypeSymbol"/> instances could be resolved.</returns>
+    public static bool TryBuildNamedTypeSymbolMap<T>(
+        this Compilation compilation,
+        IEnumerable<KeyValuePair<T, string>> typeNames,
+        [NotNullWhen(true)] out ImmutableDictionary<T, INamedTypeSymbol>? typeSymbols)
+        where T : IEquatable<T>
+    {
+        ImmutableDictionary<T, INamedTypeSymbol>.Builder builder = ImmutableDictionary.CreateBuilder<T, INamedTypeSymbol>();
+
+        foreach (KeyValuePair<T, string> pair in typeNames)
+        {
+            if (compilation.GetTypeByMetadataName(pair.Value) is not INamedTypeSymbol attributeSymbol)
+            {
+                typeSymbols = null;
+
+                return false;
+            }
+
+            builder.Add(pair.Key, attributeSymbol);
+        }
+
+        typeSymbols = builder.ToImmutable();
+
+        return true;
+    }
 }