Rollup merge of #102021 - lcnr:tyConst-fun, r=b-naber,BoxyUwU

some post-valtree cleanup

r? project-const-generics cc ```@b-naber```

12 files changed, 58 insertions, 122 deletions

diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs
index d9c4ae4d53f..1c33e7845cb 100644
--- a/compiler/rustc_const_eval/src/const_eval/mod.rs
+++ b/compiler/rustc_const_eval/src/const_eval/mod.rs
@@ -100,10 +100,10 @@ pub(crate) fn try_destructure_mir_constant<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     val: mir::ConstantKind<'tcx>,
-) -> InterpResult<'tcx, mir::DestructuredMirConstant<'tcx>> {
+) -> InterpResult<'tcx, mir::DestructuredConstant<'tcx>> {
     trace!("destructure_mir_constant: {:?}", val);
     let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
-    let op = ecx.mir_const_to_op(&val, None)?;
+    let op = ecx.const_to_op(&val, None)?;
 
     // We go to `usize` as we cannot allocate anything bigger anyway.
     let (field_count, variant, down) = match val.ty().kind() {
@@ -129,7 +129,7 @@ pub(crate) fn try_destructure_mir_constant<'tcx>(
         .collect::<InterpResult<'tcx, Vec<_>>>()?;
     let fields = tcx.arena.alloc_from_iter(fields_iter);
 
-    Ok(mir::DestructuredMirConstant { variant, fields })
+    Ok(mir::DestructuredConstant { variant, fields })
 }
 
 #[instrument(skip(tcx), level = "debug")]
@@ -139,7 +139,7 @@ pub(crate) fn deref_mir_constant<'tcx>(
     val: mir::ConstantKind<'tcx>,
 ) -> mir::ConstantKind<'tcx> {
     let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
-    let op = ecx.mir_const_to_op(&val, None).unwrap();
+    let op = ecx.const_to_op(&val, None).unwrap();
     let mplace = ecx.deref_operand(&op).unwrap();
     if let Some(alloc_id) = mplace.ptr.provenance {
         assert_eq!(
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 3177537fee2..bdebfbb3ff5 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -683,11 +683,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.stack_mut().push(frame);
 
         // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check).
-        for const_ in &body.required_consts {
-            let span = const_.span;
-            let const_ =
-                self.subst_from_current_frame_and_normalize_erasing_regions(const_.literal)?;
-            self.mir_const_to_op(&const_, None).map_err(|err| {
+        for ct in &body.required_consts {
+            let span = ct.span;
+            let ct = self.subst_from_current_frame_and_normalize_erasing_regions(ct.literal)?;
+            self.const_to_op(&ct, None).map_err(|err| {
                 // If there was an error, set the span of the current frame to this constant.
                 // Avoiding doing this when evaluation succeeds.
                 self.frame_mut().loc = Err(span);
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index 29c745a0886..dc5305aabcf 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -534,7 +534,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // * During ConstProp, with `TooGeneric` or since the `required_consts` were not all
                 //   checked yet.
                 // * During CTFE, since promoteds in `const`/`static` initializer bodies can fail.
-                self.mir_const_to_op(&val, layout)?
+                self.const_to_op(&val, layout)?
             }
         };
         trace!("{:?}: {:?}", mir_op, *op);
@@ -549,50 +549,42 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         ops.iter().map(|op| self.eval_operand(op, None)).collect()
     }
 
-    // Used when the miri-engine runs into a constant and for extracting information from constants
-    // in patterns via the `const_eval` module
-    /// The `val` and `layout` are assumed to already be in our interpreter
-    /// "universe" (param_env).
     pub fn const_to_op(
         &self,
-        c: ty::Const<'tcx>,
-        layout: Option<TyAndLayout<'tcx>>,
-    ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
-        match c.kind() {
-            ty::ConstKind::Param(_) | ty::ConstKind::Placeholder(..) => throw_inval!(TooGeneric),
-            ty::ConstKind::Error(DelaySpanBugEmitted { reported, .. }) => {
-                throw_inval!(AlreadyReported(reported))
-            }
-            ty::ConstKind::Unevaluated(uv) => {
-                // NOTE: We evaluate to a `ValTree` here as a check to ensure
-                // we're working with valid constants, even though we never need it.
-                let instance = self.resolve(uv.def, uv.substs)?;
-                let cid = GlobalId { instance, promoted: None };
-                let _valtree = self
-                    .tcx
-                    .eval_to_valtree(self.param_env.and(cid))?
-                    .unwrap_or_else(|| bug!("unable to create ValTree for {:?}", uv));
-
-                Ok(self.eval_to_allocation(cid)?.into())
-            }
-            ty::ConstKind::Bound(..) | ty::ConstKind::Infer(..) => {
-                span_bug!(self.cur_span(), "const_to_op: Unexpected ConstKind {:?}", c)
-            }
-            ty::ConstKind::Value(valtree) => {
-                let ty = c.ty();
-                let const_val = self.tcx.valtree_to_const_val((ty, valtree));
-                self.const_val_to_op(const_val, ty, layout)
-            }
-        }
-    }
-
-    pub fn mir_const_to_op(
-        &self,
         val: &mir::ConstantKind<'tcx>,
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
         match val {
-            mir::ConstantKind::Ty(ct) => self.const_to_op(*ct, layout),
+            mir::ConstantKind::Ty(ct) => {
+                match ct.kind() {
+                    ty::ConstKind::Param(_) | ty::ConstKind::Placeholder(..) => {
+                        throw_inval!(TooGeneric)
+                    }
+                    ty::ConstKind::Error(DelaySpanBugEmitted { reported, .. }) => {
+                        throw_inval!(AlreadyReported(reported))
+                    }
+                    ty::ConstKind::Unevaluated(uv) => {
+                        // NOTE: We evaluate to a `ValTree` here as a check to ensure
+                        // we're working with valid constants, even though we never need it.
+                        let instance = self.resolve(uv.def, uv.substs)?;
+                        let cid = GlobalId { instance, promoted: None };
+                        let _valtree = self
+                            .tcx
+                            .eval_to_valtree(self.param_env.and(cid))?
+                            .unwrap_or_else(|| bug!("unable to create ValTree for {uv:?}"));
+
+                        Ok(self.eval_to_allocation(cid)?.into())
+                    }
+                    ty::ConstKind::Bound(..) | ty::ConstKind::Infer(..) => {
+                        span_bug!(self.cur_span(), "unexpected ConstKind in ctfe: {ct:?}")
+                    }
+                    ty::ConstKind::Value(valtree) => {
+                        let ty = ct.ty();
+                        let const_val = self.tcx.valtree_to_const_val((ty, valtree));
+                        self.const_val_to_op(const_val, ty, layout)
+                    }
+                }
+            }
             mir::ConstantKind::Val(val, ty) => self.const_val_to_op(*val, *ty, layout),
             mir::ConstantKind::Unevaluated(uv, _) => {
                 let instance = self.resolve(uv.def, uv.substs)?;
diff --git a/compiler/rustc_middle/src/mir/interpret/queries.rs b/compiler/rustc_middle/src/mir/interpret/queries.rs
index 4207988d700..a8c7505329c 100644
--- a/compiler/rustc_middle/src/mir/interpret/queries.rs
+++ b/compiler/rustc_middle/src/mir/interpret/queries.rs
@@ -211,7 +211,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         constant: mir::ConstantKind<'tcx>,
-    ) -> mir::DestructuredMirConstant<'tcx> {
+    ) -> mir::DestructuredConstant<'tcx> {
         self.try_destructure_mir_constant(param_env.and(constant)).unwrap()
     }
 }
diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs
index d89efe2b3f0..efd7357afc4 100644
--- a/compiler/rustc_middle/src/mir/query.rs
+++ b/compiler/rustc_middle/src/mir/query.rs
@@ -392,16 +392,9 @@ pub enum ClosureOutlivesSubject<'tcx> {
     Region(ty::RegionVid),
 }
 
-/// The constituent parts of a type level constant of kind ADT or array.
-#[derive(Copy, Clone, Debug, HashStable)]
-pub struct DestructuredConst<'tcx> {
-    pub variant: Option<VariantIdx>,
-    pub fields: &'tcx [ty::Const<'tcx>],
-}
-
 /// The constituent parts of a mir constant of kind ADT or array.
 #[derive(Copy, Clone, Debug, HashStable)]
-pub struct DestructuredMirConstant<'tcx> {
+pub struct DestructuredConstant<'tcx> {
     pub variant: Option<VariantIdx>,
     pub fields: &'tcx [ConstantKind<'tcx>],
 }
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 53c254119f4..1afea4864b8 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1007,7 +1007,9 @@ rustc_queries! {
 
     /// Tries to destructure an `mir::ConstantKind` ADT or array into its variant index
     /// and its field values.
-    query try_destructure_mir_constant(key: ty::ParamEnvAnd<'tcx, mir::ConstantKind<'tcx>>) -> Option<mir::DestructuredMirConstant<'tcx>> {
+    query try_destructure_mir_constant(
+        key: ty::ParamEnvAnd<'tcx, mir::ConstantKind<'tcx>>
+    ) -> Option<mir::DestructuredConstant<'tcx>> {
         desc { "destructuring mir constant"}
         remap_env_constness
     }
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index 339ff4d3593..4bc821dcfa1 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -1,9 +1,6 @@
 use crate::mir::interpret::LitToConstInput;
 use crate::mir::ConstantKind;
-use crate::ty::{
-    self, InlineConstSubsts, InlineConstSubstsParts, InternalSubsts, ParamEnv, ParamEnvAnd, Ty,
-    TyCtxt, TypeVisitable,
-};
+use crate::ty::{self, InternalSubsts, ParamEnv, ParamEnvAnd, Ty, TyCtxt};
 use rustc_data_structures::intern::Interned;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
@@ -151,46 +148,6 @@ impl<'tcx> Const<'tcx> {
         }
     }
 
-    pub fn from_inline_const(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
-        debug!("Const::from_inline_const(def_id={:?})", def_id);
-
-        let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-
-        let body_id = match tcx.hir().get(hir_id) {
-            hir::Node::AnonConst(ac) => ac.body,
-            _ => span_bug!(
-                tcx.def_span(def_id.to_def_id()),
-                "from_inline_const can only process anonymous constants"
-            ),
-        };
-
-        let expr = &tcx.hir().body(body_id).value;
-
-        let ty = tcx.typeck(def_id).node_type(hir_id);
-
-        let ret = match Self::try_eval_lit_or_param(tcx, ty, expr) {
-            Some(v) => v,
-            None => {
-                let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id());
-                let parent_substs =
-                    tcx.erase_regions(InternalSubsts::identity_for_item(tcx, typeck_root_def_id));
-                let substs =
-                    InlineConstSubsts::new(tcx, InlineConstSubstsParts { parent_substs, ty })
-                        .substs;
-                tcx.mk_const(ty::ConstS {
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                        def: ty::WithOptConstParam::unknown(def_id).to_global(),
-                        substs,
-                        promoted: (),
-                    }),
-                    ty,
-                })
-            }
-        };
-        debug_assert!(!ret.has_free_regions());
-        ret
-    }
-
     /// Interns the given value as a constant.
     #[inline]
     pub fn from_value(tcx: TyCtxt<'tcx>, val: ty::ValTree<'tcx>, ty: Ty<'tcx>) -> Self {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index 6bb33b5890b..11645f840c1 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -680,7 +680,7 @@ macro_rules! ClonePatternFoldableImpls {
 }
 
 ClonePatternFoldableImpls! { <'tcx>
-    Span, Field, Mutability, Symbol, LocalVarId, usize, ty::Const<'tcx>,
+    Span, Field, Mutability, Symbol, LocalVarId, usize,
     Region<'tcx>, Ty<'tcx>, BindingMode, AdtDef<'tcx>,
     SubstsRef<'tcx>, &'tcx GenericArg<'tcx>, UserType<'tcx>,
     UserTypeProjection, CanonicalUserTypeAnnotation<'tcx>
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 08ba3f9941d..cb134a20ea0 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -471,7 +471,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        self.ecx.mir_const_to_op(&c.literal, None).ok()
+        self.ecx.const_to_op(&c.literal, None).ok()
     }
 
     /// Returns the value, if any, of evaluating `place`.
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index f16efb365f3..2885f06b19c 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -292,7 +292,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        match self.ecx.mir_const_to_op(&c.literal, None) {
+        match self.ecx.const_to_op(&c.literal, None) {
             Ok(op) => Some(op),
             Err(error) => {
                 let tcx = self.ecx.tcx.at(c.span);
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs b/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
index 70b9c732ff4..23e04ae6a53 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
@@ -487,18 +487,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn array_length_to_const(&self, length: &hir::ArrayLen) -> ty::Const<'tcx> {
         match length {
             &hir::ArrayLen::Infer(_, span) => self.ct_infer(self.tcx.types.usize, None, span),
-            hir::ArrayLen::Body(anon_const) => self.to_const(anon_const),
+            hir::ArrayLen::Body(anon_const) => {
+                let const_def_id = self.tcx.hir().local_def_id(anon_const.hir_id);
+                let span = self.tcx.hir().span(anon_const.hir_id);
+                let c = ty::Const::from_anon_const(self.tcx, const_def_id);
+                self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
+                self.normalize_associated_types_in(span, c)
+            }
         }
     }
 
-    pub fn to_const(&self, ast_c: &hir::AnonConst) -> ty::Const<'tcx> {
-        let const_def_id = self.tcx.hir().local_def_id(ast_c.hir_id);
-        let span = self.tcx.hir().span(ast_c.hir_id);
-        let c = ty::Const::from_anon_const(self.tcx, const_def_id);
-        self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
-        self.normalize_associated_types_in(span, c)
-    }
-
     pub fn const_arg_to_const(
         &self,
         ast_c: &hir::AnonConst,
diff --git a/compiler/rustc_typeck/src/coherence/orphan.rs b/compiler/rustc_typeck/src/coherence/orphan.rs
index 1608550aa6a..87961890f53 100644
--- a/compiler/rustc_typeck/src/coherence/orphan.rs
+++ b/compiler/rustc_typeck/src/coherence/orphan.rs
@@ -5,7 +5,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_errors::{Diagnostic, ErrorGuaranteed};
 use rustc_hir as hir;
-use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::util::IgnoreRegions;
@@ -229,12 +228,8 @@ fn emit_orphan_check_error<'tcx>(
                 "only traits defined in the current crate {msg}"
             );
             err.span_label(sp, "impl doesn't use only types from inside the current crate");
-            for (ty, is_target_ty) in &tys {
-                let mut ty = *ty;
-                tcx.infer_ctxt().enter(|infcx| {
-                    // Remove the lifetimes unnecessary for this error.
-                    ty = infcx.freshen(ty);
-                });
+            for &(mut ty, is_target_ty) in &tys {
+                ty = tcx.erase_regions(ty);
                 ty = match ty.kind() {
                     // Remove the type arguments from the output, as they are not relevant.
                     // You can think of this as the reverse of `resolve_vars_if_possible`.
@@ -264,7 +259,7 @@ fn emit_orphan_check_error<'tcx>(
                 };
 
                 let msg = format!("{} is not defined in the current crate{}", ty, postfix);
-                if *is_target_ty {
+                if is_target_ty {
                     // Point at `D<A>` in `impl<A, B> for C<B> in D<A>`
                     err.span_label(self_ty_span, &msg);
                 } else {