Rollup merge of rust-lang#115972 - RalfJung:const-consistency, r=oli-obk

rename mir::Constant -> mir::ConstOperand, mir::ConstKind -> mir::Const

Also, be more consistent with the `to/eval_bits` methods... we had some that take a type and some that take a size, and then sometimes the one that takes a type is called `bits_for_ty`.

Turns out that `ty::Const`/`mir::ConstKind` carry their type with them, so we don't need to even pass the type to those `eval_bits` functions at all.

However this is not properly consistent yet: in `ty` we have most of the methods on `ty::Const`, but in `mir` we have them on `mir::ConstKind`. And indeed those two types are the ones that correspond to each other. So `mir::ConstantKind` should actually be renamed to `mir::Const`. But what to do with `mir::Constant`? It carries around a span, that's really more like a constant operand that appears as a MIR operand... it's more suited for `syntax.rs` than `consts.rs`, but the bigger question is, which name should it get if we want to align the `mir` and `ty` types? `ConstOperand`? `ConstOp`? `Literal`? It's not a literal but it has a field called `literal` so it would at least be consistently wrong-ish...

`@oli-obk` any ideas?

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -13,7 +13,7 @@ use rustc_index::IndexSlice;
 use rustc_infer::infer::LateBoundRegionConversionTime;
 use rustc_middle::mir::tcx::PlaceTy;
 use rustc_middle::mir::{
-    AggregateKind, CallSource, Constant, FakeReadCause, Local, LocalInfo, LocalKind, Location,
+    AggregateKind, CallSource, ConstOperand, FakeReadCause, Local, LocalInfo, LocalKind, Location,
     Operand, Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator,
     TerminatorKind,
 };
@@ -101,12 +101,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let terminator = self.body[location.block].terminator();
         debug!("add_moved_or_invoked_closure_note: terminator={:?}", terminator);
         if let TerminatorKind::Call {
-            func: Operand::Constant(box Constant { literal, .. }),
+            func: Operand::Constant(box ConstOperand { const_, .. }),
             args,
             ..
         } = &terminator.kind
         {
-            if let ty::FnDef(id, _) = *literal.ty().kind() {
+            if let ty::FnDef(id, _) = *const_.ty().kind() {
                 debug!("add_moved_or_invoked_closure_note: id={:?}", id);
                 if Some(self.infcx.tcx.parent(id)) == self.infcx.tcx.lang_items().fn_once_trait() {
                     let closure = match args.first() {

compiler/rustc_borrowck/src/renumber.rs

@@ -4,8 +4,7 @@ use crate::BorrowckInferCtxt;
 use rustc_index::IndexSlice;
 use rustc_infer::infer::NllRegionVariableOrigin;
 use rustc_middle::mir::visit::{MutVisitor, TyContext};
-use rustc_middle::mir::Constant;
-use rustc_middle::mir::{Body, Location, Promoted};
+use rustc_middle::mir::{Body, ConstOperand, Location, Promoted};
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
 use rustc_span::{Span, Symbol};
@@ -117,9 +116,9 @@ impl<'a, 'tcx> MutVisitor<'tcx> for RegionRenumberer<'a, 'tcx> {
     }
 
     #[instrument(skip(self), level = "debug")]
-    fn visit_constant(&mut self, constant: &mut Constant<'tcx>, location: Location) {
-        let literal = constant.literal;
-        constant.literal = self.renumber_regions(literal, || RegionCtxt::Location(location));
+    fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, location: Location) {
+        let const_ = constant.const_;
+        constant.const_ = self.renumber_regions(const_, || RegionCtxt::Location(location));
         debug!("constant: {:#?}", constant);
     }
 }

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -302,11 +302,11 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
         self.sanitize_place(place, location, context);
     }
 
-    fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
+    fn visit_constant(&mut self, constant: &ConstOperand<'tcx>, location: Location) {
         debug!(?constant, ?location, "visit_constant");
 
         self.super_constant(constant, location);
-        let ty = self.sanitize_type(constant, constant.literal.ty());
+        let ty = self.sanitize_type(constant, constant.const_.ty());
 
         self.cx.infcx.tcx.for_each_free_region(&ty, |live_region| {
             let live_region_vid =
@@ -328,7 +328,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
 
         if let Some(annotation_index) = constant.user_ty {
             if let Err(terr) = self.cx.relate_type_and_user_type(
-                constant.literal.ty(),
+                constant.const_.ty(),
                 ty::Variance::Invariant,
                 &UserTypeProjection { base: annotation_index, projs: vec![] },
                 locations,
@@ -340,20 +340,20 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                     constant,
                     "bad constant user type {:?} vs {:?}: {:?}",
                     annotation,
-                    constant.literal.ty(),
+                    constant.const_.ty(),
                     terr,
                 );
             }
         } else {
             let tcx = self.tcx();
-            let maybe_uneval = match constant.literal {
-                ConstantKind::Ty(ct) => match ct.kind() {
+            let maybe_uneval = match constant.const_ {
+                Const::Ty(ct) => match ct.kind() {
                     ty::ConstKind::Unevaluated(_) => {
-                        bug!("should not encounter unevaluated ConstantKind::Ty here, got {:?}", ct)
+                        bug!("should not encounter unevaluated Const::Ty here, got {:?}", ct)
                     }
                     _ => None,
                 },
-                ConstantKind::Unevaluated(uv, _) => Some(uv),
+                Const::Unevaluated(uv, _) => Some(uv),
                 _ => None,
             };
 
@@ -384,15 +384,15 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                     check_err(self, promoted_body, ty, promoted_ty);
                 } else {
                     self.cx.ascribe_user_type(
-                        constant.literal.ty(),
+                        constant.const_.ty(),
                         UserType::TypeOf(uv.def, UserArgs { args: uv.args, user_self_ty: None }),
                         locations.span(&self.cx.body),
                     );
                 }
             } else if let Some(static_def_id) = constant.check_static_ptr(tcx) {
                 let unnormalized_ty = tcx.type_of(static_def_id).instantiate_identity();
                 let normalized_ty = self.cx.normalize(unnormalized_ty, locations);
-                let literal_ty = constant.literal.ty().builtin_deref(true).unwrap().ty;
+                let literal_ty = constant.const_.ty().builtin_deref(true).unwrap().ty;
 
                 if let Err(terr) = self.cx.eq_types(
                     literal_ty,
@@ -404,7 +404,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                 }
             }
 
-            if let ty::FnDef(def_id, args) = *constant.literal.ty().kind() {
+            if let ty::FnDef(def_id, args) = *constant.const_.ty().kind() {
                 let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, args);
                 self.cx.normalize_and_prove_instantiated_predicates(
                     def_id,
@@ -1801,9 +1801,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         debug!(?op, ?location, "check_operand");
 
         if let Operand::Constant(constant) = op {
-            let maybe_uneval = match constant.literal {
-                ConstantKind::Val(..) | ConstantKind::Ty(_) => None,
-                ConstantKind::Unevaluated(uv, _) => Some(uv),
+            let maybe_uneval = match constant.const_ {
+                Const::Val(..) | Const::Ty(_) => None,
+                Const::Unevaluated(uv, _) => Some(uv),
             };
 
             if let Some(uv) = maybe_uneval {

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -64,9 +64,9 @@ pub(crate) fn codegen_tls_ref<'tcx>(
 
 pub(crate) fn eval_mir_constant<'tcx>(
     fx: &FunctionCx<'_, '_, 'tcx>,
-    constant: &Constant<'tcx>,
+    constant: &ConstOperand<'tcx>,
 ) -> (ConstValue<'tcx>, Ty<'tcx>) {
-    let cv = fx.monomorphize(constant.literal);
+    let cv = fx.monomorphize(constant.const_);
     // This cannot fail because we checked all required_consts in advance.
     let val = cv
         .eval(fx.tcx, ty::ParamEnv::reveal_all(), Some(constant.span))
@@ -76,7 +76,7 @@ pub(crate) fn eval_mir_constant<'tcx>(
 
 pub(crate) fn codegen_constant_operand<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
-    constant: &Constant<'tcx>,
+    constant: &ConstOperand<'tcx>,
 ) -> CValue<'tcx> {
     let (const_val, ty) = eval_mir_constant(fx, constant);
     codegen_const_value(fx, const_val, ty)

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -252,8 +252,8 @@ pub(crate) fn codegen_inline_asm<'tcx>(
                 CInlineAsmOperand::Const { value }
             }
             InlineAsmOperand::SymFn { ref value } => {
-                let literal = fx.monomorphize(value.literal);
-                if let ty::FnDef(def_id, args) = *literal.ty().kind() {
+                let const_ = fx.monomorphize(value.const_);
+                if let ty::FnDef(def_id, args) = *const_.ty().kind() {
                     let instance = ty::Instance::resolve_for_fn_ptr(
                         fx.tcx,
                         ty::ParamEnv::reveal_all(),

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -660,12 +660,12 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
         }
         _ => match ct.ty().kind() {
             ty::Int(ity) => {
-                let bits = ct.eval_bits(tcx, ty::ParamEnv::reveal_all(), ct.ty());
+                let bits = ct.eval_bits(tcx, ty::ParamEnv::reveal_all());
                 let val = Integer::from_int_ty(&tcx, *ity).size().sign_extend(bits) as i128;
                 write!(output, "{val}")
             }
             ty::Uint(_) => {
-                let val = ct.eval_bits(tcx, ty::ParamEnv::reveal_all(), ct.ty());
+                let val = ct.eval_bits(tcx, ty::ParamEnv::reveal_all());
                 write!(output, "{val}")
             }
             ty::Bool => {

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1098,8 +1098,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     InlineAsmOperandRef::Const { string }
                 }
                 mir::InlineAsmOperand::SymFn { ref value } => {
-                    let literal = self.monomorphize(value.literal);
-                    if let ty::FnDef(def_id, args) = *literal.ty().kind() {
+                    let const_ = self.monomorphize(value.const_);
+                    if let ty::FnDef(def_id, args) = *const_.ty().kind() {
                         let instance = ty::Instance::resolve_for_fn_ptr(
                             bx.tcx(),
                             ty::ParamEnv::reveal_all(),

compiler/rustc_codegen_ssa/src/mir/constant.rs

@@ -13,37 +13,37 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn eval_mir_constant_to_operand(
         &self,
         bx: &mut Bx,
-        constant: &mir::Constant<'tcx>,
+        constant: &mir::ConstOperand<'tcx>,
     ) -> OperandRef<'tcx, Bx::Value> {
         let val = self.eval_mir_constant(constant);
         let ty = self.monomorphize(constant.ty());
         OperandRef::from_const(bx, val, ty)
     }
 
-    pub fn eval_mir_constant(&self, constant: &mir::Constant<'tcx>) -> mir::ConstValue<'tcx> {
-        self.monomorphize(constant.literal)
+    pub fn eval_mir_constant(&self, constant: &mir::ConstOperand<'tcx>) -> mir::ConstValue<'tcx> {
+        self.monomorphize(constant.const_)
             .eval(self.cx.tcx(), ty::ParamEnv::reveal_all(), Some(constant.span))
             .expect("erroneous constant not captured by required_consts")
     }
 
     /// This is a convenience helper for `simd_shuffle_indices`. It has the precondition
-    /// that the given `constant` is an `ConstantKind::Unevaluated` and must be convertible to
+    /// that the given `constant` is an `Const::Unevaluated` and must be convertible to
     /// a `ValTree`. If you want a more general version of this, talk to `wg-const-eval` on zulip.
     ///
     /// Note that this function is cursed, since usually MIR consts should not be evaluated to valtrees!
     pub fn eval_unevaluated_mir_constant_to_valtree(
         &self,
-        constant: &mir::Constant<'tcx>,
+        constant: &mir::ConstOperand<'tcx>,
     ) -> Result<Option<ty::ValTree<'tcx>>, ErrorHandled> {
-        let uv = match self.monomorphize(constant.literal) {
-            mir::ConstantKind::Unevaluated(uv, _) => uv.shrink(),
-            mir::ConstantKind::Ty(c) => match c.kind() {
+        let uv = match self.monomorphize(constant.const_) {
+            mir::Const::Unevaluated(uv, _) => uv.shrink(),
+            mir::Const::Ty(c) => match c.kind() {
                 // A constant that came from a const generic but was then used as an argument to old-style
                 // simd_shuffle (passing as argument instead of as a generic param).
                 rustc_type_ir::ConstKind::Value(valtree) => return Ok(Some(valtree)),
                 other => span_bug!(constant.span, "{other:#?}"),
             },
-            // We should never encounter `ConstantKind::Val` unless MIR opts (like const prop) evaluate
+            // We should never encounter `Const::Val` unless MIR opts (like const prop) evaluate
             // a constant and write that value back into `Operand`s. This could happen, but is unlikely.
             // Also: all users of `simd_shuffle` are on unstable and already need to take a lot of care
             // around intrinsics. For an issue to happen here, it would require a macro expanding to a
@@ -65,7 +65,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn simd_shuffle_indices(
         &mut self,
         bx: &Bx,
-        constant: &mir::Constant<'tcx>,
+        constant: &mir::ConstOperand<'tcx>,
     ) -> (Bx::Value, Ty<'tcx>) {
         let ty = self.monomorphize(constant.ty());
         let val = self

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -1089,7 +1089,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
     pub fn eval_mir_constant(
         &self,
-        val: &mir::ConstantKind<'tcx>,
+        val: &mir::Const<'tcx>,
         span: Option<Span>,
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -692,7 +692,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
             Constant(constant) => {
                 let c =
-                    self.subst_from_current_frame_and_normalize_erasing_regions(constant.literal)?;
+                    self.subst_from_current_frame_and_normalize_erasing_regions(constant.const_)?;
 
                 // This can still fail:
                 // * During ConstProp, with `TooGeneric` or since the `required_consts` were not all

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

@@ -346,20 +346,20 @@ where
     };
 
     // Check the qualifs of the value of `const` items.
-    let uneval = match constant.literal {
-        ConstantKind::Ty(ct)
+    let uneval = match constant.const_ {
+        Const::Ty(ct)
             if matches!(
                 ct.kind(),
                 ty::ConstKind::Param(_) | ty::ConstKind::Error(_) | ty::ConstKind::Value(_)
             ) =>
         {
             None
         }
-        ConstantKind::Ty(c) => {
+        Const::Ty(c) => {
             bug!("expected ConstKind::Param or ConstKind::Value here, found {:?}", c)
         }
-        ConstantKind::Unevaluated(uv, _) => Some(uv),
-        ConstantKind::Val(..) => None,
+        Const::Unevaluated(uv, _) => Some(uv),
+        Const::Val(..) => None,
     };
 
     if let Some(mir::UnevaluatedConst { def, args: _, promoted }) = uneval {
@@ -383,5 +383,5 @@ where
     }
 
     // Otherwise use the qualifs of the type.
-    Q::in_any_value_of_ty(cx, constant.literal.ty())
+    Q::in_any_value_of_ty(cx, constant.const_.ty())
 }

compiler/rustc_const_eval/src/transform/promote_consts.rs

@@ -372,7 +372,7 @@ impl<'tcx> Validator<'_, 'tcx> {
                                     StatementKind::Assign(box (
                                         _,
                                         Rvalue::Use(Operand::Constant(c)),
-                                    )) => c.literal.try_eval_target_usize(self.tcx, self.param_env),
+                                    )) => c.const_.try_eval_target_usize(self.tcx, self.param_env),
                                     _ => None,
                                 }
                             } else {
@@ -554,7 +554,7 @@ impl<'tcx> Validator<'_, 'tcx> {
                             // Integer division: the RHS must be a non-zero const.
                             let const_val = match rhs {
                                 Operand::Constant(c) => {
-                                    c.literal.try_eval_bits(self.tcx, self.param_env, lhs_ty)
+                                    c.const_.try_eval_bits(self.tcx, self.param_env)
                                 }
                                 _ => None,
                             };
@@ -766,10 +766,10 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                     if self.keep_original {
                         rhs.clone()
                     } else {
-                        let unit = Rvalue::Use(Operand::Constant(Box::new(Constant {
+                        let unit = Rvalue::Use(Operand::Constant(Box::new(ConstOperand {
                             span: statement.source_info.span,
                             user_ty: None,
-                            literal: ConstantKind::zero_sized(self.tcx.types.unit),
+                            const_: Const::zero_sized(self.tcx.types.unit),
                         })));
                         mem::replace(rhs, unit)
                     },
@@ -844,10 +844,10 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                 let args = tcx.erase_regions(GenericArgs::identity_for_item(tcx, def));
                 let uneval = mir::UnevaluatedConst { def, args, promoted: Some(promoted_id) };
 
-                Operand::Constant(Box::new(Constant {
+                Operand::Constant(Box::new(ConstOperand {
                     span,
                     user_ty: None,
-                    literal: ConstantKind::Unevaluated(uneval, ty),
+                    const_: Const::Unevaluated(uneval, ty),
                 }))
             };
 
@@ -1041,8 +1041,8 @@ pub fn is_const_fn_in_array_repeat_expression<'tcx>(
         if let Some(Terminator { kind: TerminatorKind::Call { func, destination, .. }, .. }) =
             &block.terminator
         {
-            if let Operand::Constant(box Constant { literal, .. }) = func {
-                if let ty::FnDef(def_id, _) = *literal.ty().kind() {
+            if let Operand::Constant(box ConstOperand { const_, .. }) = func {
+                if let ty::FnDef(def_id, _) = *const_.ty().kind() {
                     if destination == place {
                         if ccx.tcx.is_const_fn(def_id) {
                             return true;