diff --git a/tools/aapt2/ResourceParser.cpp b/tools/aapt2/ResourceParser.cpp
index 90f713b67985b..6dfabf1e9aba0 100644
--- a/tools/aapt2/ResourceParser.cpp
+++ b/tools/aapt2/ResourceParser.cpp
@@ -934,7 +934,7 @@ bool ResourceParser::ParseAttrImpl(xml::XmlPullParser* parser,
   }
 
   struct SymbolComparator {
-    bool operator()(const Attribute::Symbol& a, const Attribute::Symbol& b) {
+    bool operator()(const Attribute::Symbol& a, const Attribute::Symbol& b) const {
       return a.symbol.name.value() < b.symbol.name.value();
     }
   };