Auto merge of #91354 - fee1-dead:const_env, r=spastorino

Cleanup: Eliminate ConstnessAnd

This is almost a behaviour-free change and purely a refactoring. "almost" because we appear to be using the wrong ParamEnv somewhere already, and this is now exposed by failing a test using the unstable `~const` feature.

We most definitely need to review all `without_const` and at some point should probably get rid of many of them by using `TraitPredicate` instead of `TraitRef`.

This is a continuation of https://github.com/rust-lang/rust/pull/90274.

r? `@oli-obk`

cc `@spastorino` `@ecstatic-morse`

4 files changed, 6 insertions, 4 deletions

diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index 6d3a89c0a8a..c5412affafe 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -7,6 +7,7 @@ use crate::interpret::{
 };
 
 use rustc_errors::ErrorReported;
+use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::ErrorHandled;
@@ -215,6 +216,7 @@ pub fn eval_to_const_value_raw_provider<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: ty::ParamEnvAnd<'tcx, GlobalId<'tcx>>,
 ) -> ::rustc_middle::mir::interpret::EvalToConstValueResult<'tcx> {
+    assert!(key.param_env.constness() == hir::Constness::Const);
     // see comment in eval_to_allocation_raw_provider for what we're doing here
     if key.param_env.reveal() == Reveal::All {
         let mut key = key;
@@ -249,6 +251,7 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: ty::ParamEnvAnd<'tcx, GlobalId<'tcx>>,
 ) -> ::rustc_middle::mir::interpret::EvalToAllocationRawResult<'tcx> {
+    assert!(key.param_env.constness() == hir::Constness::Const);
     // Because the constant is computed twice (once per value of `Reveal`), we are at risk of
     // reporting the same error twice here. To resolve this, we check whether we can evaluate the
     // constant in the more restrictive `Reveal::UserFacing`, which most likely already was
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index cf084faade8..6206deb2115 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -918,6 +918,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         } else {
             self.param_env
         };
+        let param_env = param_env.with_const();
         let val = self.tcx.eval_to_allocation_raw(param_env.and(gid))?;
         self.raw_const_to_mplace(val)
     }
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index 274665ccd98..f9e65ea9075 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -817,8 +817,7 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> {
                     );
 
                     let implsrc = tcx.infer_ctxt().enter(|infcx| {
-                        let mut selcx =
-                            SelectionContext::with_constness(&infcx, hir::Constness::Const);
+                        let mut selcx = SelectionContext::new(&infcx);
                         selcx.select(&obligation)
                     });
 
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
index abc5a3c6a52..43612292f52 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -3,7 +3,6 @@
 //! See the `Qualif` trait for more info.
 
 use rustc_errors::ErrorReported;
-use rustc_hir as hir;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, subst::SubstsRef, AdtDef, Ty};
@@ -167,7 +166,7 @@ impl Qualif for NeedsNonConstDrop {
         );
 
         let implsrc = cx.tcx.infer_ctxt().enter(|infcx| {
-            let mut selcx = SelectionContext::with_constness(&infcx, hir::Constness::Const);
+            let mut selcx = SelectionContext::new(&infcx);
             selcx.select(&obligation)
         });
         !matches!(