1 files changed, 1 insertions, 1 deletions
diff --git a/src/System.Private.CoreLib/shared/System/Globalization/CultureData.cs b/src/System.Private.CoreLib/shared/System/Globalization/CultureData.cs
index fda239c51..5eb9f44f8 100644
--- a/src/System.Private.CoreLib/shared/System/Globalization/CultureData.cs
+++ b/src/System.Private.CoreLib/shared/System/Globalization/CultureData.cs
@@ -2268,7 +2268,7 @@ namespace System.Globalization
             for (int i = startIndex; i < format.Length; ++i)
             {
                 // See if we have a time Part
-                if (!inQuote && timeParts.IndexOf(format[i]) != -1)
+                if (!inQuote && timeParts.Contains(format[i]))
                 {
                     return i;
                 }