rebase and remove dead code

compiler/rustc_const_eval/src/const_eval/mod.rs

@@ -172,40 +172,6 @@ pub(crate) fn try_destructure_const<'tcx>(
     Ok(mir::DestructuredConst { variant, fields })
 }
 
-pub(crate) fn destructure_mir_constant<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
-    val: mir::ConstantKind<'tcx>,
-) -> mir::DestructuredMirConstant<'tcx> {
-    trace!("destructure_const: {:?}", val);
-    let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
-    let op = ecx.mir_const_to_op(&val, None).unwrap();
-
-    // We go to `usize` as we cannot allocate anything bigger anyway.
-    let (field_count, variant, down) = match val.ty().kind() {
-        ty::Array(_, len) => (usize::try_from(len.eval_usize(tcx, param_env)).unwrap(), None, op),
-        ty::Adt(def, _) if def.variants().is_empty() => {
-            return mir::DestructuredMirConstant { variant: None, fields: &[] };
-        }
-        ty::Adt(def, _) => {
-            let variant = ecx.read_discriminant(&op).unwrap().1;
-            let down = ecx.operand_downcast(&op, variant).unwrap();
-            (def.variants()[variant].fields.len(), Some(variant), down)
-        }
-        ty::Tuple(substs) => (substs.len(), None, op),
-        _ => bug!("cannot destructure constant {:?}", val),
-    };
-
-    let fields_iter = (0..field_count).map(|i| {
-        let field_op = ecx.operand_field(&down, i).unwrap();
-        let val = op_to_const(&ecx, &field_op);
-        mir::ConstantKind::Val(val, field_op.layout.ty)
-    });
-    let fields = tcx.arena.alloc_from_iter(fields_iter);
-
-    mir::DestructuredMirConstant { variant, fields }
-}
-
 pub(crate) fn deref_const<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -241,39 +207,3 @@ pub(crate) fn deref_const<'tcx>(
 
     tcx.mk_const(ty::ConstS { val: ty::ConstKind::Value(op_to_const(&ecx, &mplace.into())), ty })
 }
-
-#[instrument(skip(tcx), level = "debug")]
-pub(crate) fn deref_mir_constant<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'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 mplace = ecx.deref_operand(&op).unwrap();
-    if let Some(alloc_id) = mplace.ptr.provenance {
-        assert_eq!(
-            tcx.get_global_alloc(alloc_id).unwrap().unwrap_memory().0.0.mutability,
-            Mutability::Not,
-            "deref_const cannot be used with mutable allocations as \
-            that could allow pattern matching to observe mutable statics",
-        );
-    }
-
-    let ty = match mplace.meta {
-        MemPlaceMeta::None => mplace.layout.ty,
-        MemPlaceMeta::Poison => bug!("poison metadata in `deref_const`: {:#?}", mplace),
-        // In case of unsized types, figure out the real type behind.
-        MemPlaceMeta::Meta(scalar) => match mplace.layout.ty.kind() {
-            ty::Str => bug!("there's no sized equivalent of a `str`"),
-            ty::Slice(elem_ty) => tcx.mk_array(*elem_ty, scalar.to_machine_usize(&tcx).unwrap()),
-            _ => bug!(
-                "type {} should not have metadata, but had {:?}",
-                mplace.layout.ty,
-                mplace.meta
-            ),
-        },
-    };
-
-    mir::ConstantKind::Val(op_to_const(&ecx, &mplace.into()), ty)
-}

compiler/rustc_const_eval/src/lib.rs

@@ -45,10 +45,6 @@ pub fn provide(providers: &mut Providers) {
         let (param_env, value) = param_env_and_value.into_parts();
         const_eval::try_destructure_const(tcx, param_env, value).ok()
     };
-    providers.destructure_mir_constant = |tcx, param_env_and_value| {
-        let (param_env, value) = param_env_and_value.into_parts();
-        const_eval::destructure_mir_constant(tcx, param_env, value)
-    };
     providers.const_to_valtree = |tcx, param_env_and_value| {
         let (param_env, raw) = param_env_and_value.into_parts();
         const_eval::const_to_valtree(tcx, param_env, raw)
@@ -57,8 +53,4 @@ pub fn provide(providers: &mut Providers) {
         let (param_env, value) = param_env_and_value.into_parts();
         const_eval::deref_const(tcx, param_env, value)
     };
-    providers.deref_mir_constant = |tcx, param_env_and_value| {
-        let (param_env, value) = param_env_and_value.into_parts();
-        const_eval::deref_mir_constant(tcx, param_env, value)
-    }
 }

compiler/rustc_middle/src/mir/mod.rs

@@ -2721,8 +2721,8 @@ impl<'tcx> ConstantKind<'tcx> {
         }
     }
 
-    #[inline]
     /// Panics if the value cannot be evaluated or doesn't contain a valid integer of the given type.
+    #[inline]
     pub fn eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> u128 {
         self.try_eval_bits(tcx, param_env, ty)
             .unwrap_or_else(|| bug!("expected bits of {:#?}, got {:#?}", ty, self))
@@ -2793,112 +2793,6 @@ impl<'tcx> ConstantKind<'tcx> {
         Self::from_bits(tcx, n as u128, ty::ParamEnv::empty().and(ty))
     }
 
-    #[instrument(skip(tcx), level = "debug")]
-    pub fn try_eval_lit_or_param(
-        tcx: TyCtxt<'tcx>,
-        ty: Ty<'tcx>,
-        expr: &'tcx hir::Expr<'tcx>,
-    ) -> Option<Self> {
-        // Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments
-        // currently have to be wrapped in curly brackets, so it's necessary to special-case.
-        let expr = match &expr.kind {
-            hir::ExprKind::Block(block, _) if block.stmts.is_empty() && block.expr.is_some() => {
-                block.expr.as_ref().unwrap()
-            }
-            _ => expr,
-        };
-
-        let lit_input = match expr.kind {
-            hir::ExprKind::Lit(ref lit) => {
-                Some(interpret::LitToConstInput { lit: &lit.node, ty, neg: false })
-            }
-            hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => match expr.kind {
-                hir::ExprKind::Lit(ref lit) => {
-                    Some(interpret::LitToConstInput { lit: &lit.node, ty, neg: true })
-                }
-                _ => None,
-            },
-            _ => None,
-        };
-
-        if let Some(lit_input) = lit_input {
-            // If an error occurred, ignore that it's a literal and leave reporting the error up to
-            // mir.
-            match tcx.at(expr.span).lit_to_mir_constant(lit_input) {
-                Ok(c) => return Some(c),
-                Err(e) => {
-                    tcx.sess.delay_span_bug(
-                        expr.span,
-                        &format!("Const::from_anon_const: couldn't lit_to_const {:?}", e),
-                    );
-                }
-            }
-        }
-        use hir::{def::DefKind::ConstParam, def::Res, ExprKind, Path, QPath};
-        match expr.kind {
-            ExprKind::Path(QPath::Resolved(_, &Path { res: Res::Def(ConstParam, def_id), .. })) => {
-                // Find the name and index of the const parameter by indexing the generics of
-                // the parent item and construct a `ParamConst`.
-                let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
-                let item_id = tcx.hir().get_parent_node(hir_id);
-                let item_def_id = tcx.hir().local_def_id(item_id);
-                let generics = tcx.generics_of(item_def_id.to_def_id());
-                let index = generics.param_def_id_to_index[&def_id];
-                let name = tcx.hir().name(hir_id);
-                let ty_const = tcx.mk_const(ty::ConstS {
-                    val: ty::ConstKind::Param(ty::ParamConst::new(index, name)),
-                    ty,
-                });
-
-                Some(Self::Ty(ty_const))
-            }
-            _ => None,
-        }
-    }
-
-    #[instrument(skip(tcx), level = "debug")]
-    pub fn from_inline_const(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
-        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 = ty::InlineConstSubsts::new(
-                    tcx,
-                    ty::InlineConstSubstsParts { parent_substs, ty },
-                )
-                .substs;
-                let ty_const = tcx.mk_const(ty::ConstS {
-                    val: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                        def: ty::WithOptConstParam::unknown(def_id).to_global(),
-                        substs,
-                        promoted: None,
-                    }),
-                    ty,
-                });
-
-                Self::Ty(ty_const)
-            }
-        };
-        debug_assert!(!ret.has_free_regions());
-        ret
-    }
-
     /// Literals are converted to `ConstantKindVal`, const generic parameters are eagerly
     /// converted to a constant, everything else becomes `Unevaluated`.
     pub fn from_anon_const(

compiler/rustc_middle/src/mir/query.rs

@@ -1,6 +1,6 @@
 //! Values computed by queries that use MIR.
 
-use crate::mir::{self, Body, Promoted};
+use crate::mir::{Body, Promoted};
 use crate::ty::{self, OpaqueHiddenType, Ty, TyCtxt};
 use rustc_data_structures::stable_map::FxHashMap;
 use rustc_data_structures::vec_map::VecMap;
@@ -421,13 +421,6 @@ pub struct DestructuredConst<'tcx> {
     pub fields: &'tcx [ty::Const<'tcx>],
 }
 
-/// The constituent parts of an ADT or array.
-#[derive(Copy, Clone, Debug, HashStable)]
-pub struct DestructuredMirConstant<'tcx> {
-    pub variant: Option<VariantIdx>,
-    pub fields: &'tcx [mir::ConstantKind<'tcx>],
-}
-
 /// Coverage information summarized from a MIR if instrumented for source code coverage (see
 /// compiler option `-Cinstrument-coverage`). This information is generated by the
 /// `InstrumentCoverage` MIR pass and can be retrieved via the `coverageinfo` query.

compiler/rustc_middle/src/query/mod.rs

@@ -940,13 +940,6 @@ rustc_queries! {
         remap_env_constness
     }
 
-    /// Destructure an `mir::ConstantKind` ADT or array into its variant index
-    /// and its field values.
-    query destructure_mir_constant(key: ty::ParamEnvAnd<'tcx, mir::ConstantKind<'tcx>>) -> mir::DestructuredMirConstant<'tcx> {
-        desc { "destructure mir constant"}
-        remap_env_constness
-    }
-
     /// Dereference a constant reference or raw pointer and turn the result into a constant
     /// again.
     query deref_const(
@@ -956,15 +949,6 @@ rustc_queries! {
         remap_env_constness
     }
 
-    /// Dereference a constant reference or raw pointer and turn the result into a constant
-    /// again.
-    query deref_mir_constant(
-        key: ty::ParamEnvAnd<'tcx, mir::ConstantKind<'tcx>>
-    ) -> mir::ConstantKind<'tcx> {
-        desc { "deref constant" }
-        remap_env_constness
-    }
-
     query const_caller_location(key: (rustc_span::Symbol, u32, u32)) -> ConstValue<'tcx> {
         desc { "get a &core::panic::Location referring to a span" }
     }

compiler/rustc_mir_build/src/thir/cx/mod.rs

@@ -5,7 +5,6 @@
 use crate::thir::pattern::pat_from_hir;
 use crate::thir::util::UserAnnotatedTyHelpers;
 
-use rustc_ast::ast;
 use rustc_data_structures::steal::Steal;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
@@ -13,10 +12,8 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::HirId;
 use rustc_hir::Node;
 use rustc_middle::middle::region;
-use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput};
-use rustc_middle::mir::ConstantKind;
 use rustc_middle::thir::*;
-use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::Span;
 
 crate fn thir_body<'tcx>(
@@ -78,24 +75,6 @@ impl<'tcx> Cx<'tcx> {
         }
     }
 
-    #[instrument(skip(self), level = "debug")]
-    crate fn const_eval_literal(
-        &mut self,
-        lit: &'tcx ast::LitKind,
-        ty: Ty<'tcx>,
-        sp: Span,
-        neg: bool,
-    ) -> ConstantKind<'tcx> {
-        match self.tcx.at(sp).lit_to_mir_constant(LitToConstInput { lit, ty, neg }) {
-            Ok(c) => c,
-            Err(LitToConstError::Reported) => {
-                // create a dummy value and continue compiling
-                ConstantKind::Ty(self.tcx.const_error(ty))
-            }
-            Err(LitToConstError::TypeError) => bug!("const_eval_literal: had type error"),
-        }
-    }
-
     crate fn pattern_from_hir(&mut self, p: &hir::Pat<'_>) -> Pat<'tcx> {
         let p = match self.tcx.hir().get(p.hir_id) {
             Node::Pat(p) | Node::Binding(p) => p,

compiler/rustc_mir_build/src/thir/pattern/mod.rs

@@ -739,7 +739,6 @@ impl<'tcx> PatternFoldable<'tcx> for PatKind<'tcx> {
     }
 }
 
-// FIXME: Get rid of this function once valtrees land
 #[instrument(skip(tcx), level = "debug")]
 crate fn compare_const_vals<'tcx>(
     tcx: TyCtxt<'tcx>,
@@ -759,8 +758,7 @@ crate fn compare_const_vals<'tcx>(
 
     // Early return for equal constants (so e.g. references to ZSTs can be compared, even if they
     // are just integer addresses).
-    // FIXME This might be wrong
+    if a.val() == b.val() {
-    if a == b {
         return from_bool(true);
     }