diff --git a/Upsilon/Parser/ParameterToken.cs b/Upsilon/Parser/ParameterToken.cs
index 515e5e8..179131b 100644
--- a/Upsilon/Parser/ParameterToken.cs
+++ b/Upsilon/Parser/ParameterToken.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Upsilon.Text;
 
 namespace Upsilon.Parser
 {
@@ -6,12 +7,15 @@ namespace Upsilon.Parser
     {
         public ParameterToken(IdentifierToken typeName, IdentifierToken identifierName)
         {
-            IdentifierName = identifierName;
             TypeName = typeName;
+            IdentifierName = identifierName;
+            var start = identifierName.Span.Start;
+            if (typeName != null) start = typeName.Span.Start;
+            Span = new TextSpan(start, identifierName.Span.End - start);
         }
 
-        public IdentifierToken IdentifierName { get; }
         public IdentifierToken TypeName { get; }
+        public IdentifierToken IdentifierName { get; }
 
         public override SyntaxKind Kind => SyntaxKind.Parameter;
         public override IEnumerable<SyntaxNode> ChildNodes()