diff --git a/internal/encoding/encoding.go b/internal/encoding/encoding.go
index e720284..379e378 100644
--- a/internal/encoding/encoding.go
+++ b/internal/encoding/encoding.go
@@ -395,7 +395,7 @@
 	case *ast.Ellipsis:
 		check(n, constraints, "ellipsis", true)
 
-	case *ast.Ident, *ast.SelectorExpr, *ast.Alias:
+	case *ast.Ident, *ast.SelectorExpr, *ast.Alias, *ast.LetClause:
 		check(n, i.References, "references", true)
 
 	default: