diff --git a/Source/cmGeneratorExpressionParser.cxx b/Source/cmGeneratorExpressionParser.cxx
index 341832a18..64d992a31 100644
--- a/Source/cmGeneratorExpressionParser.cxx
+++ b/Source/cmGeneratorExpressionParser.cxx
@@ -192,6 +192,10 @@ void cmGeneratorExpressionParser::ParseGeneratorExpression(
           {
           extendText(result, *commaIt);
           }
+        else
+          {
+          break;
+          }
         }
       }
     return;