diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index 71f870a76..c7bf2cc75 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -53,6 +53,7 @@ instance HasCategory Category where
   toCategoryName = \case
     ArrayLiteral -> "array"
     BinaryOperator -> "binary operator"
+    Boolean -> "boolean"
     DictionaryLiteral -> "dictionary"
     Error -> "error"
     ExpressionStatements -> "expression statements"