diff --git a/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/ConditionParser.cs b/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/ConditionParser.cs
index b5e2e809ae4..757492d15e4 100644
--- a/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/ConditionParser.cs
+++ b/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/ConditionParser.cs
@@ -205,19 +205,30 @@ ConditionExpression ParseFunctionExpression (string function_name)
 		{
 			List <ConditionFactorExpression> list = new List <ConditionFactorExpression> ();
 			ConditionFactorExpression e;
-			
+
+            /* starts looking at the open paren, move past it */
+            tokenizer.GetNextToken ();
+            if (tokenizer.Token.Type == TokenType.RightParen) {
+                /* leave us looking past the end of the argument list */
+                tokenizer.GetNextToken ();
+                return list;
+            }
 			while (true) {
-				tokenizer.GetNextToken ();
-				if (tokenizer.Token.Type == TokenType.RightParen) {
-					tokenizer.GetNextToken ();
-					break;
-				}
-				if (tokenizer.Token.Type == TokenType.Comma)
+                e = (ConditionFactorExpression) ParseFactorExpression ();
+                list.Add (e);
+                /* ParseFactorExpression leaves us looking at what follows the
+                 * expression */
+                if (tokenizer.Token.Type == TokenType.RightParen) {
+                    /* leave us looking past the end of the argument list */
+                    tokenizer.GetNextToken ();
+                    break;
+                }
+                if (tokenizer.Token.Type == TokenType.Comma) {
+                    tokenizer.GetNextToken ();
 					continue;
-					
-				tokenizer.Putback (tokenizer.Token);
-				e = (ConditionFactorExpression) ParseFactorExpression ();
-				list.Add (e);
+                }
+
+                throw new ExpressionParseException (String.Format ("Unexpected token {0} in argument list while parsing condition \"{1}\"", tokenizer.Token, conditionStr));
 			}
 			
 			return list;