miri calls resolve_for_fn_ptr when reifying.

src/librustc_mir/interpret/cast.rs

@@ -44,7 +44,14 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         if self.tcx.has_attr(def_id, sym::rustc_args_required_const) {
                             bug!("reifying a fn ptr that requires const arguments");
                         }
-                        let instance = self.resolve(def_id, substs)?;
+
+                        let instance = ty::Instance::resolve_for_fn_ptr(
+                            *self.tcx,
+                            self.param_env,
+                            def_id,
+                            substs,
+                        ).ok_or_else(|| err_inval!(TooGeneric))?;
+
                         let fn_ptr = self.memory.create_fn_alloc(FnVal::Instance(instance));
                         self.write_scalar(Scalar::Ptr(fn_ptr.into()), dest)?;
                     }