Rollup merge of rust-lang#63495 - eddyb:mir-constant-ty, r=oli-obk

 Remove redundant `ty` fields from `mir::Constant` and `hair::pattern::PatternRange`.

Fixes rust-lang#56137.

As a side-effect, associated const literals have the correct type now, which should make things easier for rust-lang#61041.

r? @oli-obk / @matthewjasper cc @davidtwco @varkor

Author: Centril

src/librustc/mir/mod.rs

@@ -2197,7 +2197,6 @@ impl<'tcx> Operand<'tcx> {
         let ty = tcx.type_of(def_id).subst(tcx, substs);
         Operand::Constant(box Constant {
             span,
-            ty,
             user_ty: None,
             literal: ty::Const::zero_sized(tcx, ty),
         })
@@ -2476,7 +2475,6 @@ impl<'tcx> Debug for Rvalue<'tcx> {
 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
 pub struct Constant<'tcx> {
     pub span: Span,
-    pub ty: Ty<'tcx>,
 
     /// Optional user-given type: for something like
     /// `collect::<Vec<_>>`, this would be present and would
@@ -3385,12 +3383,11 @@ impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
     fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         Constant {
             span: self.span.clone(),
-            ty: self.ty.fold_with(folder),
             user_ty: self.user_ty.fold_with(folder),
             literal: self.literal.fold_with(folder),
         }
     }
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        self.ty.visit_with(visitor) || self.literal.visit_with(visitor)
+        self.literal.visit_with(visitor)
     }
 }

src/librustc/mir/tcx.rs

@@ -252,7 +252,7 @@ impl<'tcx> Operand<'tcx> {
         match self {
             &Operand::Copy(ref l) |
             &Operand::Move(ref l) => l.ty(local_decls, tcx).ty,
-            &Operand::Constant(ref c) => c.ty,
+            &Operand::Constant(ref c) => c.literal.ty,
         }
     }
 }

src/librustc/mir/visit.rs

@@ -782,13 +782,11 @@ macro_rules! make_mir_visitor {
                               location: Location) {
                 let Constant {
                     span,
-                    ty,
                     user_ty,
                     literal,
                 } = constant;
 
                 self.visit_span(span);
-                self.visit_ty(ty, TyContext::Location(location));
                 drop(user_ty); // no visit method for this
                 self.visit_const(literal, location);
             }

src/librustc_codegen_ssa/mir/analyze.rs

@@ -221,7 +221,7 @@ impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
             mir::TerminatorKind::Call {
                 func: mir::Operand::Constant(ref c),
                 ref args, ..
-            } => match c.ty.sty {
+            } => match c.literal.ty.sty {
                 ty::FnDef(did, _) => Some((did, args)),
                 _ => None,
             },

src/librustc_codegen_ssa/mir/block.rs

@@ -651,7 +651,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             let (llval, ty) = self.simd_shuffle_indices(
                                 &bx,
                                 constant.span,
-                                constant.ty,
+                                constant.literal.ty,
                                 c,
                             );
                             return OperandRef {

src/librustc_codegen_ssa/mir/operand.rs

@@ -466,7 +466,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             mir::Operand::Constant(ref constant) => {
-                let ty = self.monomorphize(&constant.ty);
                 self.eval_mir_constant(constant)
                     .map(|c| OperandRef::from_const(bx, c))
                     .unwrap_or_else(|err| {
@@ -481,6 +480,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         // the above error (or silence it under some conditions) will not cause UB
                         bx.abort();
                         // We've errored, so we don't have to produce working code.
+                        let ty = self.monomorphize(&constant.literal.ty);
                         let layout = bx.cx().layout_of(ty);
                         bx.load_operand(PlaceRef::new_sized(
                             bx.cx().const_undef(bx.cx().type_ptr_to(bx.cx().backend_type(layout))),

src/librustc_mir/borrow_check/nll/type_check/mod.rs

@@ -272,12 +272,11 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
 
     fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
         self.super_constant(constant, location);
-        self.sanitize_constant(constant, location);
-        self.sanitize_type(constant, constant.ty);
+        self.sanitize_type(constant, constant.literal.ty);
 
         if let Some(annotation_index) = constant.user_ty {
             if let Err(terr) = self.cx.relate_type_and_user_type(
-                constant.ty,
+                constant.literal.ty,
                 ty::Variance::Invariant,
                 &UserTypeProjection { base: annotation_index, projs: vec![], },
                 location.to_locations(),
@@ -289,7 +288,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                     constant,
                     "bad constant user type {:?} vs {:?}: {:?}",
                     annotation,
-                    constant.ty,
+                    constant.literal.ty,
                     terr,
                 );
             }
@@ -299,7 +298,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                     location.to_locations(),
                     ConstraintCategory::Boring,
                     self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
-                        constant.ty, def_id, UserSubsts { substs, user_self_ty: None },
+                        constant.literal.ty, def_id, UserSubsts { substs, user_self_ty: None },
                     )),
                 ) {
                     span_mirbug!(
@@ -403,41 +402,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
         }
     }
 
-    /// Checks that the constant's `ty` field matches up with what would be
-    /// expected from its literal. Unevaluated constants and well-formed
-    /// constraints are checked by `visit_constant`.
-    fn sanitize_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
-        debug!(
-            "sanitize_constant(constant={:?}, location={:?})",
-            constant, location
-        );
-
-        let literal = constant.literal;
-
-        if let ConstValue::Unevaluated(..) = literal.val {
-            return;
-        }
-
-        debug!("sanitize_constant: expected_ty={:?}", literal.ty);
-
-        if let Err(terr) = self.cx.eq_types(
-            literal.ty,
-            constant.ty,
-            location.to_locations(),
-            ConstraintCategory::Boring,
-        ) {
-            span_mirbug!(
-                self,
-                constant,
-                "constant {:?} should have type {:?} but has {:?} ({:?})",
-                constant,
-                literal.ty,
-                constant.ty,
-                terr,
-            );
-        }
-    }
-
     /// Checks that the types internal to the `place` match up with
     /// what would be expected.
     fn sanitize_place(

src/librustc_mir/build/expr/as_constant.rs

@@ -38,9 +38,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         inferred_ty: ty,
                     })
                 });
+                assert_eq!(literal.ty, ty);
                 Constant {
                     span,
-                    ty,
                     user_ty,
                     literal,
                 }

src/librustc_mir/build/expr/as_rvalue.rs

@@ -591,7 +591,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let n = (!0u128) >> (128 - bits);
         let literal = ty::Const::from_bits(self.hir.tcx(), n, param_ty);
 
-        self.literal_operand(span, ty, literal)
+        self.literal_operand(span, literal)
     }
 
     // Helper to get the minimum value of the appropriate type
@@ -602,6 +602,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let n = 1 << (bits - 1);
         let literal = ty::Const::from_bits(self.hir.tcx(), n, param_ty);
 
-        self.literal_operand(span, ty, literal)
+        self.literal_operand(span, literal)
     }
 }

src/librustc_mir/build/expr/into.rs

@@ -114,7 +114,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     destination,
                     Constant {
                         span: expr_span,
-                        ty: this.hir.bool_ty(),
                         user_ty: None,
                         literal: this.hir.true_literal(),
                     },
@@ -126,7 +125,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     destination,
                     Constant {
                         span: expr_span,
-                        ty: this.hir.bool_ty(),
                         user_ty: None,
                         literal: this.hir.false_literal(),
                     },