Remove fast path for perf

Author: BoxyUwU

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -646,20 +646,20 @@ pub fn try_evaluate_const<'tcx>(
                 // it is well formed as otherwise CTFE will ICE. For the same reasons as with
                 // deferring evaluation of generic/uninferred constants, we do not have to worry
                 // about `generic_const_expr`
-                if tcx.def_kind(uv.def) == DefKind::AnonConst
-                    && tcx.predicates_of(uv.def).predicates.is_empty()
-                {
-                    // ... skip doing any work
-                } else {
-                    let input = infcx
-                        .canonicalize_query(param_env.and(uv), &mut OriginalQueryValues::default());
-                    if !tcx.check_constant_safe_to_evaluate(input) {
-                        let e = tcx.dcx().delayed_bug(
-                            "Attempted to evaluate illformed constant but no error emitted",
-                        );
-                        return Err(EvaluateConstErr::EvaluationFailure(e));
-                    }
-                }
+                // if tcx.def_kind(uv.def) == DefKind::AnonConst
+                //     && tcx.predicates_of(uv.def).predicates.is_empty()
+                // {
+                //     // ... skip doing any work
+                // } else {
+                //     let input = infcx
+                //         .canonicalize_query(param_env.and(uv), &mut OriginalQueryValues::default());
+                //     if !tcx.check_constant_safe_to_evaluate(input) {
+                //         let e = tcx.dcx().delayed_bug(
+                //             "Attempted to evaluate illformed constant but no error emitted",
+                //         );
+                //         return Err(EvaluateConstErr::EvaluationFailure(e));
+                //     }
+                // }
 
                 let typing_env = infcx
                     .typing_env(tcx.erase_regions(param_env))
@@ -670,6 +670,17 @@ pub fn try_evaluate_const<'tcx>(
             let uv = ty::UnevaluatedConst::new(uv.def, args);
             let erased_uv = tcx.erase_regions(uv);
 
+            if !tcx.features().generic_const_exprs() {
+                let input = infcx
+                    .canonicalize_query(param_env.and(uv), &mut OriginalQueryValues::default());
+                if !tcx.check_constant_safe_to_evaluate(input) {
+                    let e = tcx.dcx().delayed_bug(
+                        "Attempted to evaluate illformed constant but no error emitted",
+                    );
+                    return Err(EvaluateConstErr::EvaluationFailure(e));
+                }
+            }
+
             use rustc_middle::mir::interpret::ErrorHandled;
             match tcx.const_eval_resolve_for_typeck(typing_env, erased_uv, DUMMY_SP) {
                 Ok(Ok(val)) => Ok(ty::Const::new_value(