Introduce the ITypedDecl interface.

src/Bridge/Declaration.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Cxxi;
 
 namespace Cxxi
 {
@@ -8,6 +9,11 @@ namespace Cxxi
         Declaration PreviousDecl { get; }
     }
 
+    public interface ITypedDecl
+    {
+        Type Type { get; }
+    }
+
     /// <summary>
     /// Represents a C++ declaration.
     /// </summary>

src/Bridge/Field.cs

@@ -3,7 +3,7 @@ namespace Cxxi
     /// <summary>
     /// Represents a a C/C++ record field Decl.
     /// </summary>
-    public class Field : Declaration
+    public class Field : Declaration, ITypedDecl
     {
         public Type Type { get; set; }
         public AccessSpecifier Access { get; set; }

src/Bridge/Function.cs

@@ -21,7 +21,7 @@ namespace Cxxi
         Unknown
     }
 
-    public class Parameter : Declaration
+    public class Parameter : Declaration, ITypedDecl
     {
         public Parameter()
         {