refactor Adjustment to use new PointerCast enum

Author: Saleem Jaffer

src/librustc/middle/expr_use_visitor.rs

@@ -705,11 +705,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
             debug!("walk_adjustment expr={:?} adj={:?}", expr, adjustment);
             match adjustment.kind {
                 adjustment::Adjust::NeverToAny |
-                adjustment::Adjust::ReifyFnPointer |
-                adjustment::Adjust::UnsafeFnPointer |
-                adjustment::Adjust::ClosureFnPointer(_) |
-                adjustment::Adjust::MutToConstPointer |
-                adjustment::Adjust::Unsize => {
+                adjustment::Adjust::Pointer(_)  => {
                     // Creating a closure/fn-pointer or unsizing consumes
                     // the input and stores it into the resulting rvalue.
                     self.delegate_consume(expr.hir_id, expr.span, &cmt);

src/librustc/middle/mem_categorization.rs

@@ -619,12 +619,8 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
             }
 
             adjustment::Adjust::NeverToAny |
-            adjustment::Adjust::ReifyFnPointer |
-            adjustment::Adjust::UnsafeFnPointer |
-            adjustment::Adjust::ClosureFnPointer(_) |
-            adjustment::Adjust::MutToConstPointer |
-            adjustment::Adjust::Borrow(_) |
-            adjustment::Adjust::Unsize => {
+            adjustment::Adjust::Pointer(_) |
+            adjustment::Adjust::Borrow(_) => {
                 // Result is an rvalue.
                 Ok(self.cat_rvalue_node(expr.hir_id, expr.span, target))
             }

src/librustc/ty/adjustment.rs

@@ -7,10 +7,29 @@ use rustc_macros::HashStable;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
 pub enum PointerCast {
+    /// Go from a fn-item type to a fn-pointer type.
     ReifyFnPointer,
+
+    /// Go from a safe fn pointer to an unsafe fn pointer.
     UnsafeFnPointer,
+
+    /// Go from a non-capturing closure to an fn pointer or an unsafe fn pointer.
+    /// It cannot convert a closure that requires unsafe.
     ClosureFnPointer(hir::Unsafety),
+
+    /// Go from a mut raw pointer to a const raw pointer.
     MutToConstPointer,
+
+    /// Unsize a pointer/reference value, e.g., `&[T; n]` to
+    /// `&[T]`. Note that the source could be a thin or fat pointer.
+    /// This will do things like convert thin pointers to fat
+    /// pointers, or convert structs containing thin pointers to
+    /// structs containing fat pointers, or convert between fat
+    /// pointers. We don't store the details of how the transform is
+    /// done (in fact, we don't know that, because it might depend on
+    /// the precise type parameters). We just store the target
+    /// type. Codegen backends and miri figure out what has to be done
+    /// based on the precise source/target type at hand.
     Unsize,
 }
 
@@ -65,36 +84,13 @@ pub enum Adjust<'tcx> {
     /// Go from ! to any type.
     NeverToAny,
 
-    /// Go from a fn-item type to a fn-pointer type.
-    ReifyFnPointer,
-
-    /// Go from a safe fn pointer to an unsafe fn pointer.
-    UnsafeFnPointer,
-
-    /// Go from a non-capturing closure to an fn pointer or an unsafe fn pointer.
-    /// It cannot convert a closure that requires unsafe.
-    ClosureFnPointer(hir::Unsafety),
-
-    /// Go from a mut raw pointer to a const raw pointer.
-    MutToConstPointer,
-
     /// Dereference once, producing a place.
     Deref(Option<OverloadedDeref<'tcx>>),
 
     /// Take the address and produce either a `&` or `*` pointer.
     Borrow(AutoBorrow<'tcx>),
 
-    /// Unsize a pointer/reference value, e.g., `&[T; n]` to
-    /// `&[T]`. Note that the source could be a thin or fat pointer.
-    /// This will do things like convert thin pointers to fat
-    /// pointers, or convert structs containing thin pointers to
-    /// structs containing fat pointers, or convert between fat
-    /// pointers. We don't store the details of how the transform is
-    /// done (in fact, we don't know that, because it might depend on
-    /// the precise type parameters). We just store the target
-    /// type. Codegen backends and miri figure out what has to be done
-    /// based on the precise source/target type at hand.
-    Unsize,
+    Pointer(PointerCast),
 }
 
 /// An overloaded autoderef step, representing a `Deref(Mut)::deref(_mut)`

src/librustc/ty/structural_impls.rs

@@ -7,6 +7,7 @@ use crate::hir::def::Namespace;
 use crate::mir::ProjectionKind;
 use crate::mir::interpret::ConstValue;
 use crate::ty::{self, Lift, Ty, TyCtxt, ConstVid};
+use crate::ty::adjustment::{PointerCast};
 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use crate::ty::print::{FmtPrinter, Printer};
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
@@ -626,16 +627,16 @@ impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjust<'a> {
         match *self {
             ty::adjustment::Adjust::NeverToAny =>
                 Some(ty::adjustment::Adjust::NeverToAny),
-            ty::adjustment::Adjust::ReifyFnPointer =>
-                Some(ty::adjustment::Adjust::ReifyFnPointer),
-            ty::adjustment::Adjust::UnsafeFnPointer =>
-                Some(ty::adjustment::Adjust::UnsafeFnPointer),
-            ty::adjustment::Adjust::ClosureFnPointer(unsafety) =>
-                Some(ty::adjustment::Adjust::ClosureFnPointer(unsafety)),
-            ty::adjustment::Adjust::MutToConstPointer =>
-                Some(ty::adjustment::Adjust::MutToConstPointer),
-            ty::adjustment::Adjust::Unsize =>
-                Some(ty::adjustment::Adjust::Unsize),
+            ty::adjustment::Adjust::Pointer(PointerCast::ReifyFnPointer) =>
+                Some(ty::adjustment::Adjust::Pointer(PointerCast::ReifyFnPointer)),
+            ty::adjustment::Adjust::Pointer(PointerCast::UnsafeFnPointer) =>
+                Some(ty::adjustment::Adjust::Pointer(PointerCast::UnsafeFnPointer)),
+            ty::adjustment::Adjust::Pointer(PointerCast::ClosureFnPointer(unsafety)) =>
+                Some(ty::adjustment::Adjust::Pointer(PointerCast::ClosureFnPointer(unsafety))),
+            ty::adjustment::Adjust::Pointer(PointerCast::MutToConstPointer) =>
+                Some(ty::adjustment::Adjust::Pointer(PointerCast::MutToConstPointer)),
+            ty::adjustment::Adjust::Pointer(PointerCast::Unsize) =>
+                Some(ty::adjustment::Adjust::Pointer(PointerCast::Unsize)),
             ty::adjustment::Adjust::Deref(ref overloaded) => {
                 tcx.lift(overloaded).map(ty::adjustment::Adjust::Deref)
             }
@@ -1185,16 +1186,22 @@ BraceStructTypeFoldableImpl! {
 EnumTypeFoldableImpl! {
     impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::Adjust<'tcx> {
         (ty::adjustment::Adjust::NeverToAny),
-        (ty::adjustment::Adjust::ReifyFnPointer),
-        (ty::adjustment::Adjust::UnsafeFnPointer),
-        (ty::adjustment::Adjust::ClosureFnPointer)(a),
-        (ty::adjustment::Adjust::MutToConstPointer),
-        (ty::adjustment::Adjust::Unsize),
+        (ty::adjustment::Adjust::Pointer)(a),
         (ty::adjustment::Adjust::Deref)(a),
         (ty::adjustment::Adjust::Borrow)(a),
     }
 }
 
+EnumTypeFoldableImpl! {
+    impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::PointerCast {
+        (ty::adjustment::PointerCast::ReifyFnPointer),
+        (ty::adjustment::PointerCast::UnsafeFnPointer),
+        (ty::adjustment::PointerCast::ClosureFnPointer)(a),
+        (ty::adjustment::PointerCast::MutToConstPointer),
+        (ty::adjustment::PointerCast::Unsize),
+    }
+}
+
 BraceStructTypeFoldableImpl! {
     impl<'tcx> TypeFoldable<'tcx> for ty::adjustment::OverloadedDeref<'tcx> {
         region, mutbl,

src/librustc_mir/hair/cx/expr.rs

@@ -7,7 +7,7 @@ use rustc_data_structures::indexed_vec::Idx;
 use rustc::hir::def::{CtorOf, Def, CtorKind};
 use rustc::mir::interpret::{GlobalId, ErrorHandled, ConstValue};
 use rustc::ty::{self, AdtKind, Ty};
-use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow, AutoBorrowMutability};
+use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow, AutoBorrowMutability, PointerCast};
 use rustc::ty::subst::{InternalSubsts, SubstsRef};
 use rustc::hir;
 use rustc::hir::def_id::LocalDefId;
@@ -75,19 +75,19 @@ fn apply_adjustment<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                                     -> Expr<'tcx> {
     let Expr { temp_lifetime, mut span, .. } = expr;
     let kind = match adjustment.kind {
-        Adjust::ReifyFnPointer => {
+        Adjust::Pointer(PointerCast::ReifyFnPointer) => {
             ExprKind::ReifyFnPointer { source: expr.to_ref() }
         }
-        Adjust::UnsafeFnPointer => {
+        Adjust::Pointer(PointerCast::UnsafeFnPointer) => {
             ExprKind::UnsafeFnPointer { source: expr.to_ref() }
         }
-        Adjust::ClosureFnPointer(unsafety) => {
+        Adjust::Pointer(PointerCast::ClosureFnPointer(unsafety)) => {
             ExprKind::ClosureFnPointer { source: expr.to_ref(), unsafety }
         }
         Adjust::NeverToAny => {
             ExprKind::NeverToAny { source: expr.to_ref() }
         }
-        Adjust::MutToConstPointer => {
+        Adjust::Pointer(PointerCast::MutToConstPointer) => {
             ExprKind::MutToConstPointer { source: expr.to_ref() }
         }
         Adjust::Deref(None) => {
@@ -187,7 +187,7 @@ fn apply_adjustment<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             // since they get rid of a borrow implicitly.
             ExprKind::Use { source: cast_expr.to_ref() }
         }
-        Adjust::Unsize => {
+        Adjust::Pointer(PointerCast::Unsize) => {
             // See the above comment for Adjust::Deref
             if let ExprKind::Block { body } = expr.kind {
                 if let Some(ref last_expr) = body.expr {

src/librustc_mir/transform/qualify_consts.rs

@@ -12,7 +12,7 @@ use rustc_target::spec::abi::Abi;
 use rustc::hir;
 use rustc::hir::def_id::DefId;
 use rustc::traits::{self, TraitEngine};
-use rustc::ty::{self, TyCtxt, Ty, TypeFoldable, adjustment::{PointerCast}};
+use rustc::ty::{self, TyCtxt, Ty, TypeFoldable};
 use rustc::ty::cast::CastTy;
 use rustc::ty::query::Providers;
 use rustc::mir::*;
@@ -1106,11 +1106,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
             Rvalue::UnaryOp(UnOp::Not, _) |
             Rvalue::NullaryOp(NullOp::SizeOf, _) |
             Rvalue::CheckedBinaryOp(..) |
-            Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), ..) |
-            Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), ..) |
-            Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), ..) |
-            Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), ..) |
-            Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), ..) |
+            Rvalue::Cast(CastKind::Pointer(_), ..) |
             Rvalue::Discriminant(..) |
             Rvalue::Len(_) |
             Rvalue::Ref(..) |

src/librustc_passes/rvalue_promotion.rs

@@ -584,12 +584,8 @@ fn check_adjustments<'a, 'tcx>(
     while let Some(adjustment) = adjustments.next() {
         match adjustment.kind {
             Adjust::NeverToAny |
-            Adjust::ReifyFnPointer |
-            Adjust::UnsafeFnPointer |
-            Adjust::ClosureFnPointer(_) |
-            Adjust::MutToConstPointer |
-            Adjust::Borrow(_) |
-            Adjust::Unsize => {}
+            Adjust::Pointer(_) |
+            Adjust::Borrow(_) => {}
 
             Adjust::Deref(_) => {
                 if let Some(next_adjustment) = adjustments.peek() {

src/librustc_typeck/check/coercion.rs

@@ -57,7 +57,9 @@ use rustc::hir::def_id::DefId;
 use rustc::infer::{Coercion, InferResult, InferOk};
 use rustc::infer::type_variable::TypeVariableOrigin;
 use rustc::traits::{self, ObligationCause, ObligationCauseCode};
-use rustc::ty::adjustment::{Adjustment, Adjust, AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
+use rustc::ty::adjustment::{
+    Adjustment, Adjust, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCast
+};
 use rustc::ty::{self, TypeAndMut, Ty, ClosureSubsts};
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::error::TypeError;
@@ -512,7 +514,7 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
         let coerce_target = self.next_ty_var(origin);
         let mut coercion = self.unify_and(coerce_target, target, |target| {
             let unsize = Adjustment {
-                kind: Adjust::Unsize,
+                kind: Adjust::Pointer(PointerCast::Unsize),
                 target
             };
             match reborrow {
@@ -661,7 +663,7 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
         debug!("coerce_from_fn_pointer(a={:?}, b={:?})", a, b);
 
         self.coerce_from_safe_fn(a, fn_ty_a, b,
-            simple(Adjust::UnsafeFnPointer), identity)
+            simple(Adjust::Pointer(PointerCast::UnsafeFnPointer)), identity)
     }
 
     fn coerce_from_fn_item(&self,
@@ -687,11 +689,17 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
                     b,
                     |unsafe_ty| {
                         vec![
-                            Adjustment { kind: Adjust::ReifyFnPointer, target: a_fn_pointer },
-                            Adjustment { kind: Adjust::UnsafeFnPointer, target: unsafe_ty },
+                            Adjustment {
+                                kind: Adjust::Pointer(PointerCast::ReifyFnPointer),
+                                target: a_fn_pointer
+                            },
+                            Adjustment {
+                                kind: Adjust::Pointer(PointerCast::UnsafeFnPointer),
+                                target: unsafe_ty
+                            },
                         ]
                     },
-                    simple(Adjust::ReifyFnPointer)
+                    simple(Adjust::Pointer(PointerCast::ReifyFnPointer))
                 )?;
 
                 obligations.extend(o2);
@@ -727,7 +735,9 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
                 let pointer_ty = self.tcx.coerce_closure_fn_ty(sig, unsafety);
                 debug!("coerce_closure_to_fn(a={:?}, b={:?}, pty={:?})",
                        a, b, pointer_ty);
-                self.unify_and(pointer_ty, b, simple(Adjust::ClosureFnPointer(unsafety)))
+                self.unify_and(pointer_ty, b, simple(
+                    Adjust::Pointer(PointerCast::ClosureFnPointer(unsafety))
+                ))
             }
             _ => self.unify_and(a, b, identity),
         }
@@ -766,7 +776,9 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
                 }]
             })
         } else if mt_a.mutbl != mutbl_b {
-            self.unify_and(a_unsafe, b, simple(Adjust::MutToConstPointer))
+            self.unify_and(
+                a_unsafe, b, simple(Adjust::Pointer(PointerCast::MutToConstPointer))
+            )
         } else {
             self.unify_and(a_unsafe, b, identity)
         }
@@ -857,7 +869,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 // The only adjustment that can produce an fn item is
                 // `NeverToAny`, so this should always be valid.
                 self.apply_adjustments(expr, vec![Adjustment {
-                    kind: Adjust::ReifyFnPointer,
+                    kind: Adjust::Pointer(PointerCast::ReifyFnPointer),
                     target: fn_ptr
                 }]);
             }

src/librustc_typeck/check/method/confirm.rs

@@ -7,7 +7,7 @@ use crate::hir::def_id::DefId;
 use rustc::ty::subst::{Subst, SubstsRef};
 use rustc::traits;
 use rustc::ty::{self, Ty, GenericParamDefKind};
-use rustc::ty::adjustment::{Adjustment, Adjust, OverloadedDeref};
+use rustc::ty::adjustment::{Adjustment, Adjust, OverloadedDeref, PointerCast};
 use rustc::ty::adjustment::{AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
 use rustc::ty::fold::TypeFoldable;
 use rustc::infer::{self, InferOk};
@@ -179,7 +179,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
                     ty: unsize_target
                 });
                 adjustments.push(Adjustment {
-                    kind: Adjust::Unsize,
+                    kind: Adjust::Pointer(PointerCast::Unsize),
                     target
                 });
             }
@@ -565,7 +565,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
             // If we have an autoref followed by unsizing at the end, fix the unsize target.
             match adjustments[..] {
                 [.., Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), .. },
-                 Adjustment { kind: Adjust::Unsize, ref mut target }] => {
+                 Adjustment { kind: Adjust::Pointer(PointerCast::Unsize), ref mut target }] => {
                     *target = method.sig.inputs()[0];
                 }
                 _ => {}

src/librustc_typeck/check/mod.rs

@@ -106,7 +106,9 @@ use rustc::ty::{
     self, AdtKind, CanonicalUserType, Ty, TyCtxt, GenericParamDefKind, Visibility,
     ToPolyTraitRef, ToPredicate, RegionKind, UserType
 };
-use rustc::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
+use rustc::ty::adjustment::{
+    Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCast
+};
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::query::Providers;
 use rustc::ty::subst::{UnpackedKind, Subst, InternalSubsts, SubstsRef, UserSelfTy, UserSubsts};
@@ -2664,7 +2666,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 }
                 if unsize {
                     adjustments.push(Adjustment {
-                        kind: Adjust::Unsize,
+                        kind: Adjust::Pointer(PointerCast::Unsize),
                         target: method.sig.inputs()[0]
                     });
                 }