diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index 63bb57f3cd453b51e313361c053bec1934cbd130..3a33d0629f2514970e39d041719059ac53c6ed79 100644
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -33,6 +33,7 @@ static const BuiltinAttrDefinition __definitions[]
      {"cfg_attr", EXPANSION},
      {"deprecated", STATIC_ANALYSIS},
      {"allow", STATIC_ANALYSIS},
+     {"allow_internal_unstable", STATIC_ANALYSIS},
      {"doc", HIR_LOWERING},
      {"must_use", STATIC_ANALYSIS},
      {"lang", HIR_LOWERING},