Rollup merge of #40104 - nagisa:mir-the-shiny, r=eddyb

[MIR] Rvalue::ty infallible + remove TypedConstVal

Feel free to r+ whenever there aren't any big bit-rot sensitive PRs in the queue.

r? @eddyb

11 files changed, 45 insertions, 96 deletions

diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index 40ebc97a78a..10761a03bec 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -983,7 +983,7 @@ pub enum Rvalue<'tcx> {
     Use(Operand<'tcx>),
 
     /// [x; 32]
-    Repeat(Operand<'tcx>, TypedConstVal<'tcx>),
+    Repeat(Operand<'tcx>, ConstUsize),
 
     /// &x or &mut x
     Ref(&'tcx Region, BorrowKind, Lvalue<'tcx>),
@@ -1038,7 +1038,8 @@ pub enum CastKind {
 
 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum AggregateKind<'tcx> {
-    Array,
+    /// The type is of the element
+    Array(Ty<'tcx>),
     Tuple,
     /// The second field is variant number (discriminant), it's equal to 0
     /// for struct and union expressions. The fourth field is active field
@@ -1135,7 +1136,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                 }
 
                 match *kind {
-                    AggregateKind::Array => write!(fmt, "{:?}", lvs),
+                    AggregateKind::Array(_) => write!(fmt, "{:?}", lvs),
 
                     AggregateKind::Tuple => {
                         match lvs.len() {
@@ -1202,19 +1203,6 @@ pub struct Constant<'tcx> {
     pub literal: Literal<'tcx>,
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable)]
-pub struct TypedConstVal<'tcx> {
-    pub ty: Ty<'tcx>,
-    pub span: Span,
-    pub value: ConstUsize,
-}
-
-impl<'tcx> Debug for TypedConstVal<'tcx> {
-    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
-        write!(fmt, "const {}", ConstInt::Usize(self.value))
-    }
-}
-
 newtype_index!(Promoted, "promoted");
 
 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
diff --git a/src/librustc/mir/tcx.rs b/src/librustc/mir/tcx.rs
index 50a80305bee..14d3876a66e 100644
--- a/src/librustc/mir/tcx.rs
+++ b/src/librustc/mir/tcx.rs
@@ -134,46 +134,45 @@ impl<'tcx> Lvalue<'tcx> {
 }
 
 impl<'tcx> Rvalue<'tcx> {
-    pub fn ty<'a, 'gcx>(&self, mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Ty<'tcx>>
+    pub fn ty<'a, 'gcx>(&self, mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx>
     {
         match *self {
-            Rvalue::Use(ref operand) => Some(operand.ty(mir, tcx)),
+            Rvalue::Use(ref operand) => operand.ty(mir, tcx),
             Rvalue::Repeat(ref operand, ref count) => {
                 let op_ty = operand.ty(mir, tcx);
-                let count = count.value.as_u64(tcx.sess.target.uint_type);
+                let count = count.as_u64(tcx.sess.target.uint_type);
                 assert_eq!(count as usize as u64, count);
-                Some(tcx.mk_array(op_ty, count as usize))
+                tcx.mk_array(op_ty, count as usize)
             }
             Rvalue::Ref(reg, bk, ref lv) => {
                 let lv_ty = lv.ty(mir, tcx).to_ty(tcx);
-                Some(tcx.mk_ref(reg,
+                tcx.mk_ref(reg,
                     ty::TypeAndMut {
                         ty: lv_ty,
                         mutbl: bk.to_mutbl_lossy()
                     }
-                ))
+                )
             }
-            Rvalue::Len(..) => Some(tcx.types.usize),
-            Rvalue::Cast(.., ty) => Some(ty),
+            Rvalue::Len(..) => tcx.types.usize,
+            Rvalue::Cast(.., ty) => ty,
             Rvalue::BinaryOp(op, ref lhs, ref rhs) => {
                 let lhs_ty = lhs.ty(mir, tcx);
                 let rhs_ty = rhs.ty(mir, tcx);
-                Some(op.ty(tcx, lhs_ty, rhs_ty))
+                op.ty(tcx, lhs_ty, rhs_ty)
             }
             Rvalue::CheckedBinaryOp(op, ref lhs, ref rhs) => {
                 let lhs_ty = lhs.ty(mir, tcx);
                 let rhs_ty = rhs.ty(mir, tcx);
                 let ty = op.ty(tcx, lhs_ty, rhs_ty);
-                let ty = tcx.intern_tup(&[ty, tcx.types.bool], false);
-                Some(ty)
+                tcx.intern_tup(&[ty, tcx.types.bool], false)
             }
             Rvalue::UnaryOp(_, ref operand) => {
-                Some(operand.ty(mir, tcx))
+                operand.ty(mir, tcx)
             }
             Rvalue::Discriminant(ref lval) => {
                 let ty = lval.ty(mir, tcx).to_ty(tcx);
                 if let ty::TyAdt(adt_def, _) = ty.sty {
-                    Some(adt_def.repr.discr_type().to_ty(tcx))
+                    adt_def.repr.discr_type().to_ty(tcx)
                 } else {
                     // Undefined behaviour, bug for now; may want to return something for
                     // the `discriminant` intrinsic later.
@@ -181,29 +180,24 @@ impl<'tcx> Rvalue<'tcx> {
                 }
             }
             Rvalue::Box(t) => {
-                Some(tcx.mk_box(t))
+                tcx.mk_box(t)
             }
             Rvalue::Aggregate(ref ak, ref ops) => {
                 match *ak {
-                    AggregateKind::Array => {
-                        if let Some(operand) = ops.get(0) {
-                            let ty = operand.ty(mir, tcx);
-                            Some(tcx.mk_array(ty, ops.len()))
-                        } else {
-                            None
-                        }
+                    AggregateKind::Array(ty) => {
+                        tcx.mk_array(ty, ops.len())
                     }
                     AggregateKind::Tuple => {
-                        Some(tcx.mk_tup(
+                        tcx.mk_tup(
                             ops.iter().map(|op| op.ty(mir, tcx)),
                             false
-                        ))
+                        )
                     }
                     AggregateKind::Adt(def, _, substs, _) => {
-                        Some(tcx.item_type(def.did).subst(tcx, substs))
+                        tcx.item_type(def.did).subst(tcx, substs)
                     }
                     AggregateKind::Closure(did, substs) => {
-                        Some(tcx.mk_closure_from_closure_substs(did, substs))
+                        tcx.mk_closure_from_closure_substs(did, substs)
                     }
                 }
             }
diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs
index 7cdbd5cae06..980d1806e78 100644
--- a/src/librustc/mir/visit.rs
+++ b/src/librustc/mir/visit.rs
@@ -235,12 +235,6 @@ macro_rules! make_mir_visitor {
                 self.super_const_usize(const_usize);
             }
 
-            fn visit_typed_const_val(&mut self,
-                                     val: & $($mutability)* TypedConstVal<'tcx>,
-                                     location: Location) {
-                self.super_typed_const_val(val, location);
-            }
-
             fn visit_local_decl(&mut self,
                                 local_decl: & $($mutability)* LocalDecl<'tcx>) {
                 self.super_local_decl(local_decl);
@@ -467,9 +461,9 @@ macro_rules! make_mir_visitor {
                     }
 
                     Rvalue::Repeat(ref $($mutability)* value,
-                                   ref $($mutability)* typed_const_val) => {
+                                   ref $($mutability)* length) => {
                         self.visit_operand(value, location);
-                        self.visit_typed_const_val(typed_const_val, location);
+                        self.visit_const_usize(length, location);
                     }
 
                     Rvalue::Ref(r, bk, ref $($mutability)* path) => {
@@ -515,7 +509,8 @@ macro_rules! make_mir_visitor {
                     Rvalue::Aggregate(ref $($mutability)* kind,
                                       ref $($mutability)* operands) => {
                         match *kind {
-                            AggregateKind::Array => {
+                            AggregateKind::Array(ref $($mutability)* ty) => {
+                                self.visit_ty(ty);
                             }
                             AggregateKind::Tuple => {
                             }
@@ -647,20 +642,6 @@ macro_rules! make_mir_visitor {
                 self.visit_literal(literal, location);
             }
 
-            fn super_typed_const_val(&mut self,
-                                     constant: & $($mutability)* TypedConstVal<'tcx>,
-                                     location: Location) {
-                let TypedConstVal {
-                    ref $($mutability)* span,
-                    ref $($mutability)* ty,
-                    ref $($mutability)* value,
-                } = *constant;
-
-                self.visit_span(span);
-                self.visit_ty(ty);
-                self.visit_const_usize(value, location);
-            }
-
             fn super_literal(&mut self,
                              literal: & $($mutability)* Literal<'tcx>,
                              location: Location) {
diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs
index 7f5d9c36ece..7c3807a5edc 100644
--- a/src/librustc_mir/build/expr/as_rvalue.rs
+++ b/src/librustc_mir/build/expr/as_rvalue.rs
@@ -148,12 +148,13 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 //     to the same MIR as `let x = ();`.
 
                 // first process the set of fields
+                let el_ty = expr.ty.sequence_element_type(this.hir.tcx());
                 let fields: Vec<_> =
                     fields.into_iter()
                           .map(|f| unpack!(block = this.as_operand(block, f)))
                           .collect();
 
-                block.and(Rvalue::Aggregate(AggregateKind::Array, fields))
+                block.and(Rvalue::Aggregate(AggregateKind::Array(el_ty), fields))
             }
             ExprKind::Tuple { fields } => { // see (*) above
                 // first process the set of fields
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index f2b89309e4a..c67bb8ec6c5 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -602,11 +602,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
 
             ExprKind::Repeat {
                 value: v.to_ref(),
-                count: TypedConstVal {
-                    ty: cx.tcx.types.usize,
-                    span: c.span,
-                    value: count
-                }
+                count: count,
             }
         }
         hir::ExprRet(ref v) => ExprKind::Return { value: v.to_ref() },
diff --git a/src/librustc_mir/hair/mod.rs b/src/librustc_mir/hair/mod.rs
index 9c7ee6a9ce8..2ee375dee08 100644
--- a/src/librustc_mir/hair/mod.rs
+++ b/src/librustc_mir/hair/mod.rs
@@ -14,7 +14,8 @@
 //! unit-tested and separated from the Rust source and compiler data
 //! structures.
 
-use rustc::mir::{BinOp, BorrowKind, Field, Literal, UnOp, TypedConstVal};
+use rustc_const_math::ConstUsize;
+use rustc::mir::{BinOp, BorrowKind, Field, Literal, UnOp};
 use rustc::hir::def_id::DefId;
 use rustc::middle::region::CodeExtent;
 use rustc::ty::subst::Substs;
@@ -219,7 +220,7 @@ pub enum ExprKind<'tcx> {
     },
     Repeat {
         value: ExprRef<'tcx>,
-        count: TypedConstVal<'tcx>,
+        count: ConstUsize,
     },
     Array {
         fields: Vec<ExprRef<'tcx>>,
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 441a9add883..e998665e035 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -752,7 +752,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     }
 
                     if Some(def.did) == self.tcx.lang_items.unsafe_cell_type() {
-                        let ty = rvalue.ty(self.mir, self.tcx).unwrap();
+                        let ty = rvalue.ty(self.mir, self.tcx);
                         self.add_type(ty);
                         assert!(self.qualif.intersects(Qualif::MUTABLE_INTERIOR));
                         // Even if the value inside may not need dropping,
diff --git a/src/librustc_mir/transform/type_check.rs b/src/librustc_mir/transform/type_check.rs
index af4a4a53905..c99c4323bb8 100644
--- a/src/librustc_mir/transform/type_check.rs
+++ b/src/librustc_mir/transform/type_check.rs
@@ -83,9 +83,8 @@ impl<'a, 'b, 'gcx, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'gcx, 'tcx> {
 
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
         self.super_rvalue(rvalue, location);
-        if let Some(ty) = rvalue.ty(self.mir, self.tcx()) {
-            self.sanitize_type(rvalue, ty);
-        }
+        let rval_ty = rvalue.ty(self.mir, self.tcx());
+        self.sanitize_type(rvalue, rval_ty);
     }
 
     fn visit_mir(&mut self, mir: &Mir<'tcx>) {
@@ -356,14 +355,10 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             StatementKind::Assign(ref lv, ref rv) => {
                 let lv_ty = lv.ty(mir, tcx).to_ty(tcx);
                 let rv_ty = rv.ty(mir, tcx);
-                if let Some(rv_ty) = rv_ty {
-                    if let Err(terr) = self.sub_types(rv_ty, lv_ty) {
-                        span_mirbug!(self, stmt, "bad assignment ({:?} = {:?}): {:?}",
-                                     lv_ty, rv_ty, terr);
-                    }
+                if let Err(terr) = self.sub_types(rv_ty, lv_ty) {
+                    span_mirbug!(self, stmt, "bad assignment ({:?} = {:?}): {:?}",
+                                 lv_ty, rv_ty, terr);
                 }
-                // FIXME: rvalue with undeterminable type - e.g. AggregateKind::Array branch that
-                // returns `None`.
             }
             StatementKind::SetDiscriminant{ ref lvalue, variant_index } => {
                 let lvalue_type = lvalue.ty(mir, tcx).to_ty(tcx);
diff --git a/src/librustc_passes/mir_stats.rs b/src/librustc_passes/mir_stats.rs
index ad20c535dec..ce02cb0e836 100644
--- a/src/librustc_passes/mir_stats.rs
+++ b/src/librustc_passes/mir_stats.rs
@@ -19,7 +19,7 @@ use rustc::mir::{Constant, Literal, Location, LocalDecl};
 use rustc::mir::{Lvalue, LvalueElem, LvalueProjection};
 use rustc::mir::{Mir, Operand, ProjectionElem};
 use rustc::mir::{Rvalue, SourceInfo, Statement, StatementKind};
-use rustc::mir::{Terminator, TerminatorKind, TypedConstVal, VisibilityScope, VisibilityScopeData};
+use rustc::mir::{Terminator, TerminatorKind, VisibilityScope, VisibilityScopeData};
 use rustc::mir::visit as mir_visit;
 use rustc::mir::visit::Visitor;
 use rustc::ty::{ClosureSubsts, TyCtxt};
@@ -191,7 +191,7 @@ impl<'a, 'tcx> mir_visit::Visitor<'tcx> for StatCollector<'a, 'tcx> {
                 // AggregateKind is not distinguished by visit API, so
                 // record it. (`super_rvalue` handles `_operands`.)
                 self.record(match *kind {
-                    AggregateKind::Array => "AggregateKind::Array",
+                    AggregateKind::Array(_) => "AggregateKind::Array",
                     AggregateKind::Tuple => "AggregateKind::Tuple",
                     AggregateKind::Adt(..) => "AggregateKind::Adt",
                     AggregateKind::Closure(..) => "AggregateKind::Closure",
@@ -297,13 +297,6 @@ impl<'a, 'tcx> mir_visit::Visitor<'tcx> for StatCollector<'a, 'tcx> {
         self.super_const_usize(const_usize);
     }
 
-    fn visit_typed_const_val(&mut self,
-                             val: &TypedConstVal<'tcx>,
-                             location: Location) {
-        self.record("TypedConstVal", val);
-        self.super_typed_const_val(val, location);
-    }
-
     fn visit_local_decl(&mut self,
                         local_decl: &LocalDecl<'tcx>) {
         self.record("LocalDecl", local_decl);
diff --git a/src/librustc_trans/mir/constant.rs b/src/librustc_trans/mir/constant.rs
index 771a5b7f366..c524d8351e0 100644
--- a/src/librustc_trans/mir/constant.rs
+++ b/src/librustc_trans/mir/constant.rs
@@ -529,7 +529,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
 
             mir::Rvalue::Repeat(ref elem, ref count) => {
                 let elem = self.const_operand(elem, span)?;
-                let size = count.value.as_u64(tcx.sess.target.uint_type);
+                let size = count.as_u64(tcx.sess.target.uint_type);
                 let fields = vec![elem.llval; size as usize];
                 self.const_array(dest_ty, &fields)
             }
@@ -548,7 +548,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                 failure?;
 
                 match *kind {
-                    mir::AggregateKind::Array => {
+                    mir::AggregateKind::Array(_) => {
                         self.const_array(dest_ty, &fields)
                     }
                     mir::AggregateKind::Adt(..) |
diff --git a/src/librustc_trans/mir/rvalue.rs b/src/librustc_trans/mir/rvalue.rs
index 037c771c97b..b6af4e52e82 100644
--- a/src/librustc_trans/mir/rvalue.rs
+++ b/src/librustc_trans/mir/rvalue.rs
@@ -95,7 +95,7 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
 
             mir::Rvalue::Repeat(ref elem, ref count) => {
                 let tr_elem = self.trans_operand(&bcx, elem);
-                let size = count.value.as_u64(bcx.tcx().sess.target.uint_type);
+                let size = count.as_u64(bcx.tcx().sess.target.uint_type);
                 let size = C_uint(bcx.ccx, size);
                 let base = base::get_dataptr(&bcx, dest.llval);
                 tvec::slice_for_each(&bcx, base, tr_elem.ty, size, |bcx, llslot| {
@@ -435,7 +435,7 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
             mir::Rvalue::Discriminant(ref lvalue) => {
                 let discr_lvalue = self.trans_lvalue(&bcx, lvalue);
                 let enum_ty = discr_lvalue.ty.to_ty(bcx.tcx());
-                let discr_ty = rvalue.ty(&*self.mir, bcx.tcx()).unwrap();
+                let discr_ty = rvalue.ty(&*self.mir, bcx.tcx());
                 let discr_type = type_of::immediate_type_of(bcx.ccx, discr_ty);
                 let discr = adt::trans_get_discr(&bcx, enum_ty, discr_lvalue.llval,
                                                   discr_lvalue.alignment, Some(discr_type), true);