Avoid rescanning unsupported input names

docs/internal/sources.md

@@ -80,6 +80,8 @@ entries are reported as conditional rather than inactive-only or definitively
 optional. Direct root-map `with` forms retain caller-map identity. Known scalar
 values remain separate from unknown scopes; accesses through untracked local
 maps report incomplete discovery rather than silently losing caller keys.
+Unsupported name expressions reuse value analysis's conservative syntax scan
+instead of recursively rescanning the same subtree.
 Invoked named templates are scanned conservatively, and
 dependency-bearing range scopes make discovery incomplete. Uncalled definitions
 and bypassed session templates are not traversed. This internal walker does not