Lots of work on type binding

Upsilon/Diagnostics.cs

@@ -1,4 +1,6 @@
 using System.Collections.Generic;
+using Upsilon.BaseTypes;
+using Upsilon.Parser;
 using Upsilon.Text;
 
 namespace Upsilon
@@ -37,6 +39,16 @@ namespace Upsilon
         {
             LogError($"Null Reference Encountered", span);
         }
+
+        public void LogUnknownType(TextSpan eSpan)
+        {
+            LogError($"Unknown Type found", eSpan);
+        }
+
+        public void LogUnknownOperator(TextSpan eSpan, SyntaxKind text, Type leftType, Type rightType)
+        {
+            LogError($"No binary operator {text} found for types '{leftType}' and '{rightType}'", eSpan);
+        }
     }
 
     public class DiagnosticsMessage
@@ -71,7 +83,7 @@ namespace Upsilon
 
         public string AfterError(int i = 5)
         {
-            return Diagnostics.ScriptString.GetSpan(Span.Start + 1, i);
+            return Diagnostics.ScriptString.GetSpan(Span.Start + Span.Length, i);
         }
 
     }