diff --git a/sources/MacOSKeyCodes.swift b/sources/MacOSKeyCodes.swift
index ef99be00f..4202ad3a8 100644
--- a/sources/MacOSKeyCodes.swift
+++ b/sources/MacOSKeyCodes.swift
@@ -37,7 +37,7 @@ struct SquirrelKeycode {
 
     if let keychar = keychar, keychar.isASCII, let codeValue = keychar.unicodeScalars.first?.value {
       // NOTE: IBus/Rime use different keycodes for uppercase/lowercase letters.
-      if keychar.isLowercase && (shift || caps) {
+      if keychar.isLowercase && (shift != caps) {
         // lowercase -> Uppercase
         return keychar.uppercased().unicodeScalars.first!.value
       }