diff --git a/src/logger.cr b/src/logger.cr
index 24ff99f..e57dddc 100644
--- a/src/logger.cr
+++ b/src/logger.cr
@@ -28,7 +28,7 @@ module Logger
       macro log_with_context(level, message)
         {% if @def && @def.annotation(LogMethod) %}
           {% anno = @def.annotation(LogMethod) %}
-          {% exclude = anno[:exclude].map(&.id) || [] of MacroId %}
+          {% exclude = (anno[:exclude] || [] of MacroId).map(&.id) %}
           {% args = @def.args.reject{|a| exclude.includes?(a.name)} %}
           {% unless args.empty? %}
             Log.with_context( {% for arg in args %} {{arg.name}}: {{arg.name}}, {% end %} ) do