X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=compiler%2Frustc_trait_selection%2Fsrc%2Ftraits%2Fwf.rs;h=e47ba64245f50732f0b95a7eddf143b5341bc555;hb=f4cca4607877b7fde56755d7750455470fb4f4f8;hp=0855d6d19736f15d91a39eb63d2bd17724005916;hpb=8ad447c4791807a096b575ccba9baec2e4ec937d;p=rust.git

diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index 0855d6d1973..e47ba64245f 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -476,9 +476,24 @@ fn compute(&mut self, arg: GenericArg<'tcx>) {
                                 ty::Binder::dummy(ty::PredicateKind::WellFormed(ct.into())),
                             ));
                         }
-                        // FIXME(generic_const_exprs): This seems wrong but I could not find a way to get this to trigger
                         ty::ConstKind::Expr(_) => {
-                            bug!("checking wfness of `ConstKind::Expr` is unsupported")
+                            // FIXME(generic_const_exprs): this doesnt verify that given `Expr(N + 1)` the
+                            // trait bound `typeof(N): Add<typeof(1)>` holds. This is currently unnecessary
+                            // as `ConstKind::Expr` is only produced via normalization of `ConstKind::Unevaluated`
+                            // which means that the `DefId` would have been typeck'd elsewhere. However in
+                            // the future we may allow directly lowering to `ConstKind::Expr` in which case
+                            // we would not be proving bounds we should.
+
+                            let predicate =
+                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct));
+                            let cause = self.cause(traits::WellFormed(None));
+                            self.out.push(traits::Obligation::with_depth(
+                                self.tcx(),
+                                cause,
+                                self.recursion_depth,
+                                self.param_env,
+                                predicate,
+                            ));
                         }
 
                         ty::ConstKind::Error(_)