Treat trait fns marked with the attr as const

1 files changed, 4 insertions, 1 deletions

diff --git a/compiler/rustc_mir/src/const_eval/fn_queries.rs b/compiler/rustc_mir/src/const_eval/fn_queries.rs
index 40419a4d201..fc7877b0a0b 100644
--- a/compiler/rustc_mir/src/const_eval/fn_queries.rs
+++ b/compiler/rustc_mir/src/const_eval/fn_queries.rs
@@ -3,7 +3,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::hir::map::blocks::FnLikeNode;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
-use rustc_span::symbol::Symbol;
+use rustc_span::symbol::{sym, Symbol};
 use rustc_target::spec::abi::Abi;
 
 /// Whether the `def_id` counts as const fn in your current crate, considering all active
@@ -60,6 +60,9 @@ fn is_const_fn_raw(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
             return true;
         }
 
+        if tcx.has_attr(def_id, sym::default_method_body_is_const) {
+            return true;
+        }
         // If the function itself is not annotated with `const`, it may still be a `const fn`
         // if it resides in a const trait impl.
         is_parent_const_impl_raw(tcx, hir_id)