diff --git a/InterfaceStubGenerator.Shared/InterfaceStubGenerator.cs b/InterfaceStubGenerator.Shared/InterfaceStubGenerator.cs
index 041775363..d33ffc17d 100644
--- a/InterfaceStubGenerator.Shared/InterfaceStubGenerator.cs
+++ b/InterfaceStubGenerator.Shared/InterfaceStubGenerator.cs
@@ -183,9 +183,9 @@ public void Initialize(GeneratorInitializationContext context)
 
         class SyntaxReceiver : ISyntaxReceiver
         {
-            public List<MethodDeclarationSyntax> CandidateMethods { get; } = new();
+            public List<MethodDeclarationSyntax> CandidateMethods { get; } = [];
 
-            public List<InterfaceDeclarationSyntax> CandidateInterfaces { get; } = new();
+            public List<InterfaceDeclarationSyntax> CandidateInterfaces { get; } = [];
 
             public void OnVisitSyntaxNode(SyntaxNode syntaxNode)
             {
diff --git a/InterfaceStubGenerator.Shared/Parser.cs b/InterfaceStubGenerator.Shared/Parser.cs
index ec43f5e4a..6665c5a1b 100644
--- a/InterfaceStubGenerator.Shared/Parser.cs
+++ b/InterfaceStubGenerator.Shared/Parser.cs
@@ -16,6 +16,7 @@ internal static class Parser
     /// <param name="refitInternalNamespace">The refit internal namespace.</param>
     /// <param name="candidateMethods">The candidate methods.</param>
     /// <param name="candidateInterfaces">The candidate interfaces.</param>
+    /// <param name="cancellationToken">The cancellation token.</param>
     /// <returns></returns>
     public static (
         List<Diagnostic> diagnostics,
@@ -28,6 +29,9 @@ ContextGenerationModel contextGenerationSpec
         CancellationToken cancellationToken
     )
     {
+        if (compilation == null)
+            throw new ArgumentNullException(nameof(compilation));
+
         refitInternalNamespace = $"{refitInternalNamespace ?? string.Empty}RefitInternalGenerated";
 
         // we're going to create a new compilation that contains the attribute.
@@ -67,7 +71,7 @@ CancellationToken cancellationToken
             foreach (var method in group)
             {
                 // Get the symbol being declared by the method
-                var methodSymbol = model.GetDeclaredSymbol(method);
+                var methodSymbol = model.GetDeclaredSymbol(method, cancellationToken: cancellationToken);
                 if (!IsRefitMethod(methodSymbol, httpMethodBaseAttributeSymbol))
                     continue;
 
@@ -85,7 +89,11 @@ CancellationToken cancellationToken
                 m => m.ContainingType,
                 SymbolEqualityComparer.Default
             )
-            .ToDictionary(g => g.Key, v => v.ToList());
+            .ToDictionary<IGrouping<INamedTypeSymbol, IMethodSymbol>, INamedTypeSymbol, List<IMethodSymbol>>(
+                g => g.Key,
+                v => [.. v],
+                SymbolEqualityComparer.Default
+            );
 
         // Look through the candidate interfaces
         var interfaceSymbols = new List<INamedTypeSymbol>();
@@ -95,7 +103,7 @@ CancellationToken cancellationToken
             foreach (var iface in group)
             {
                 // get the symbol belonging to the interface
-                var ifaceSymbol = model.GetDeclaredSymbol(iface);
+                var ifaceSymbol = model.GetDeclaredSymbol(iface, cancellationToken: cancellationToken);
 
                 // See if we already know about it, might be a dup
                 if (ifaceSymbol is null || interfaces.ContainsKey(ifaceSymbol))
@@ -162,7 +170,7 @@ sealed class PreserveAttribute : global::System.Attribute
         // Is it needed in order to get the preserve attribute display name.
         // Will the compilation ever change this.
         compilation = compilation.AddSyntaxTrees(
-            CSharpSyntaxTree.ParseText(SourceText.From(attributeText, Encoding.UTF8), options)
+            CSharpSyntaxTree.ParseText(SourceText.From(attributeText, Encoding.UTF8), options, cancellationToken: cancellationToken)
         );
 
         // get the newly bound attribute