None => return true,
};
+ // If the function belongs to a trait, then it must enable the const_trait_impl
+ // feature to use that trait function (with a const default body).
+ if tcx.trait_of_item(def_id).is_some() {
+ return true;
+ }
+
// If this crate is not using stability attributes, or this function is not claiming to be a
// stable `const fn`, that is all that is required.
if !tcx.features().staged_api || tcx.has_attr(def_id, sym::rustc_const_unstable) {
--- /dev/null
+// check-pass
+
+#![feature(staged_api)]
+#![feature(const_trait_impl)]
+#![feature(const_fn_trait_bound)]
+#![feature(const_t_try)]
+#![feature(const_try)]
+#![feature(try_trait_v2)]
+
+#![stable(feature = "foo", since = "1.0")]
+
+use std::ops::{ControlFlow, FromResidual, Try};
+
+#[stable(feature = "foo", since = "1.0")]
+pub struct T;
+
+#[stable(feature = "foo", since = "1.0")]
+#[rustc_const_unstable(feature = "const_t_try", issue = "none")]
+impl const Try for T {
+ type Output = T;
+ type Residual = T;
+
+ fn from_output(t: T) -> T {
+ t
+ }
+
+ fn branch(self) -> ControlFlow<T, T> {
+ ControlFlow::Continue(self)
+ }
+}
+
+#[stable(feature = "foo", since = "1.0")]
+#[rustc_const_unstable(feature = "const_t_try", issue = "none")]
+impl const FromResidual for T {
+ fn from_residual(t: T) -> T {
+ t
+ }
+}
+
+#[stable(feature = "foo", since = "1.0")]
+pub trait Tr {
+ #[default_method_body_is_const]
+ #[stable(feature = "foo", since = "1.0")]
+ fn bar() -> T {
+ T?
+ // Should be allowed.
+ // Must enable unstable features to call this trait fn in const contexts.
+ }
+}
+
+fn main() {}