diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 28fea276e..fe4d0fc5f 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -3529,7 +3529,7 @@ static RegisterPrimOp primop_match({
       builtins.match "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  FOO   "
       ```
 
-      Evaluates to `[ "foo" ]`.
+      Evaluates to `[ "FOO" ]`.
     )s",
     .fun = prim_match,
 });