Fix parser invalid index error that occurred when a field name was the same as an Excel function name. EPPlus treated the field name as a 'Function' even if the name was not followed by a left paranthesis to enclose the function arguments following the 'Function' name. We now treat the field name as a 'Name' rather than as a 'Function' when no left parathensis follows the field name. This is true even if the field name is the same as an Excel function name.

EPPlus/FormulaParsing/LexicalAnalysis/SourceCodeTokenizer.cs

diff --git a/EPPlus/FormulaParsing/LexicalAnalysis/SourceCodeTokenizer.cs b/EPPlus/FormulaParsing/LexicalAnalysis/SourceCodeTokenizer.cs
index a0d5d47..f397e84 100644
--- a/EPPlus/FormulaParsing/LexicalAnalysis/SourceCodeTokenizer.cs
+++ b/EPPlus/FormulaParsing/LexicalAnalysis/SourceCodeTokenizer.cs
@@ -199,7 +199,7 @@
             for (int i = 0; i < context.Result.Count; i++)
             {
                 var token=context.Result[i];
-                if (token.TokenType == TokenType.Unrecognized)
+                if (token.TokenType == TokenType.Unrecognized || token.TokenType == TokenType.Function)
                 {
                     if (i < context.Result.Count - 1)
                     {