Always use const param envs for const eval.

Nothing else makes sense, and there is no "danger" in doing so, as it only does something if there are const bounds, which are unstable. This used to happen implicitly via the inferctxt before, which was much more fragile.

5 files changed, 12 insertions, 0 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_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 2b4403b37ff..1446c84a397 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -3248,6 +3248,7 @@ impl<'hir> Node<'hir> {
             Node::Item(Item { kind: ItemKind::Const(..), .. })
             | Node::Item(Item { kind: ItemKind::Static(..), .. })
             | Node::TraitItem(TraitItem { kind: TraitItemKind::Const(..), .. })
+            | Node::AnonConst(_)
             | Node::ImplItem(ImplItem { kind: ImplItemKind::Const(..), .. }) => Constness::Const,
 
             _ => Constness::NotConst,
diff --git a/compiler/rustc_middle/src/mir/interpret/queries.rs b/compiler/rustc_middle/src/mir/interpret/queries.rs
index c63613ae3af..f9831855633 100644
--- a/compiler/rustc_middle/src/mir/interpret/queries.rs
+++ b/compiler/rustc_middle/src/mir/interpret/queries.rs
@@ -64,6 +64,7 @@ impl<'tcx> TyCtxt<'tcx> {
         cid: GlobalId<'tcx>,
         span: Option<Span>,
     ) -> EvalToConstValueResult<'tcx> {
+        let param_env = param_env.with_const();
         // Const-eval shouldn't depend on lifetimes at all, so we can erase them, which should
         // improve caching of queries.
         let inputs = self.erase_regions(param_env.and(cid));
@@ -92,6 +93,7 @@ impl<'tcx> TyCtxt<'tcx> {
         gid: GlobalId<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> Result<&'tcx mir::Allocation, ErrorHandled> {
+        let param_env = param_env.with_const();
         trace!("eval_to_allocation: Need to compute {:?}", gid);
         let raw_const = self.eval_to_allocation_raw(param_env.and(gid))?;
         Ok(self.global_alloc(raw_const.alloc_id).unwrap_memory())
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 8031eb8a1ec..896e5602618 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1323,6 +1323,11 @@ impl<'tcx> ParamEnv<'tcx> {
         self
     }
 
+    pub fn with_const(mut self) -> Self {
+        self.packed.set_tag(ParamTag { constness: hir::Constness::Const, ..self.packed.tag() });
+        self
+    }
+
     /// Returns a new parameter environment with the same clauses, but
     /// which "reveals" the true results of projections in all cases
     /// (even for associated types that are specializable). This is