Reviewer changes

Author: Nick Cameron

src/librustc/middle/typeck/check/vtable.rs

@@ -896,8 +896,8 @@ fn trait_cast_types(fcx: &FnCtxt,
         match autoref {
             &ty::AutoUnsize(ref k) |
             &ty::AutoUnsizeUniq(ref k) => trait_cast_types_unsize(fcx, k, src_ty, sp),
-            &ty::AutoPtr(_, _, Some(box ref autoref))
-            | &ty::AutoUnsafe(_, Some(box ref autoref))=> {
+            &ty::AutoPtr(_, _, Some(box ref autoref)) |
+            &ty::AutoUnsafe(_, Some(box ref autoref)) => {
                 trait_cast_types_autoref(fcx, autoref, src_ty, sp)
             }
             _ => None

src/librustc/middle/typeck/coherence.rs

@@ -157,16 +157,19 @@ fn get_base_type_def_id(inference_context: &InferCtxt,
                 ty_unboxed_closure(def_id, _) => {
                     Some(def_id)
                 }
-                ty_ptr(ty::mt {ty, ..}) | ty_rptr(_, ty::mt {ty, ..}) | ty_uniq(ty)
-                => match ty::get(ty).sty {
-                    ty_trait(box ty::TyTrait { def_id, .. }) => {
-                        Some(def_id)
-                    }
-                    _ => {
-                        fail!("get_base_type() returned a type that wasn't an \
-                               enum, struct, or trait");
+                ty_ptr(ty::mt {ty, ..}) |
+                ty_rptr(_, ty::mt {ty, ..}) |
+                ty_uniq(ty) => {
+                    match ty::get(ty).sty {
+                        ty_trait(box ty::TyTrait { def_id, .. }) => {
+                            Some(def_id)
+                        }
+                        _ => {
+                            fail!("get_base_type() returned a type that wasn't an \
+                                   enum, struct, or trait");
+                        }
                     }
-                },
+                }
                 ty_trait(box ty::TyTrait { def_id, .. }) => {
                     Some(def_id)
                 }

src/librustc/middle/typeck/infer/coercion.rs

@@ -350,8 +350,7 @@ impl<'f> Coerce<'f> {
                     }
                 })
             }
-            (&ty::ty_ptr(ty::mt{ty: t_a, ..}), &ty::ty_ptr(mt_b))
-            | (&ty::ty_rptr(_, ty::mt{ty: t_a, ..}), &ty::ty_ptr(mt_b)) => {
+            (&ty::ty_rptr(_, ty::mt{ty: t_a, ..}), &ty::ty_ptr(mt_b)) => {
                 self.unpack_actual_value(t_a, |sty_a| {
                     match self.unsize_ty(sty_a, mt_b.ty) {
                         Some((ty, kind)) => {
@@ -478,63 +477,52 @@ impl<'f> Coerce<'f> {
                b.repr(tcx));
 
         let coercion = Coercion(self.get_ref().trace.clone());
+        let r_a = self.get_ref().infcx.next_region_var(coercion);
 
-        match *sty_a {
-            ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty, ..}) => match ty::get(ty).sty {
-                ty::ty_trait(box ty::TyTrait {
-                        def_id,
-                        ref substs,
-                        bounds,
-                        ..
-                    }) => {
-                    let tr = ty::mk_trait(tcx, def_id, substs.clone(), bounds);
-                    let r_a = self.get_ref().infcx.next_region_var(coercion);
-                    let a_borrowed = ty::mk_rptr(tcx, r_a, ty::mt{ mutbl: b_mutbl, ty: tr });
-
-                    try!(self.subtype(a_borrowed, b));
-                    Ok(Some(AutoDerefRef(AutoDerefRef {
-                        autoderefs: 1,
-                        autoref: Some(AutoPtr(r_a, b_mutbl, None))
-                    })))
-                }
-                _ => {
-                    self.subtype(a, b)
-                }
-            },
-            _ => {
-                self.subtype(a, b)
-            }
-        }
+        self.coerce_object(a, sty_a, b,
+                           |tr| ty::mk_rptr(tcx, r_a, ty::mt{ mutbl: b_mutbl, ty: tr }),
+                           || AutoPtr(r_a, b_mutbl, None))
     }
 
     fn coerce_unsafe_object(&self,
-                              a: ty::t,
-                              sty_a: &ty::sty,
-                              b: ty::t,
-                              b_mutbl: ast::Mutability) -> CoerceResult
+                            a: ty::t,
+                            sty_a: &ty::sty,
+                            b: ty::t,
+                            b_mutbl: ast::Mutability) -> CoerceResult
     {
         let tcx = self.get_ref().infcx.tcx;
 
         debug!("coerce_unsafe_object(a={}, sty_a={:?}, b={})",
                a.repr(tcx), sty_a,
                b.repr(tcx));
 
+        self.coerce_object(a, sty_a, b,
+                           |tr| ty::mk_ptr(tcx, ty::mt{ mutbl: b_mutbl, ty: tr }),
+                           || AutoUnsafe(b_mutbl, None))
+    }
+
+    fn coerce_object(&self,
+                     a: ty::t,
+                     sty_a: &ty::sty,
+                     b: ty::t,
+                     mk_ty: |ty::t| -> ty::t,
+                     mk_adjust: || -> ty::AutoRef) -> CoerceResult
+    {
+        let tcx = self.get_ref().infcx.tcx;
+
         match *sty_a {
-            ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty, ..}) |
-            ty::ty_ptr(ty::mt{ty, ..}) => match ty::get(ty).sty {
+            ty::ty_uniq(ty) | ty::ty_rptr(_, ty::mt{ty, ..}) => match ty::get(ty).sty {
                 ty::ty_trait(box ty::TyTrait {
                         def_id,
                         ref substs,
                         bounds,
                         ..
                     }) => {
                     let tr = ty::mk_trait(tcx, def_id, substs.clone(), bounds);
-                    let a_raw = ty::mk_ptr(tcx, ty::mt{ mutbl: b_mutbl, ty: tr });
-
-                    try!(self.subtype(a_raw, b));
+                    try!(self.subtype(mk_ty(tr), b));
                     Ok(Some(AutoDerefRef(AutoDerefRef {
                         autoderefs: 1,
-                        autoref: Some(AutoUnsafe(b_mutbl, None))
+                        autoref: Some(mk_adjust())
                     })))
                 }
                 _ => {

src/test/compile-fail/dst-bad-coercions.rs

@@ -8,21 +8,44 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// Test implicit coercions involving DSTs and raw pointers.
+
 struct S;
 trait T {}
 impl T for S {}
 
+struct Foo<Sized? T> {
+    f: T
+}
+
 pub fn main() {
+    // Test that we cannot convert from *-ptr to &-ptr
     let x: *const S = &S;
-    let y: &S = x; //~ ERROR mismatched types: expected `&S`, found `*const S` (expected &-ptr
-    let y: &T = x; //~ ERROR  mismatched types: expected `&T`, found `*const S` (expected &-ptr
+    let y: &S = x; //~ ERROR mismatched types
+    let y: &T = x; //~ ERROR mismatched types
 
+    // Test that we cannot convert from *-ptr to &-ptr (mut version)
     let x: *mut S = &mut S;
-    let y: &S = x; //~ ERROR mismatched types: expected `&S`, found `*mut S` (expected &-ptr
-    let y: &T = x; //~ ERROR  mismatched types: expected `&T`, found `*mut S` (expected &-ptr
+    let y: &S = x; //~ ERROR mismatched types
+    let y: &T = x; //~ ERROR mismatched types
 
+    // Test that we cannot convert an immutable ptr to a mutable one using *-ptrs
     let x: &mut T = &S; //~ ERROR types differ in mutability
     let x: *mut T = &S; //~ ERROR types differ in mutability
     let x: *mut S = &S;
-    //~^ ERROR mismatched types: expected `*mut S`, found `&S` (values differ in mutability)
-}
+    //~^ ERROR mismatched types
+
+    // The below four sets of tests test that we cannot implicitly deref a *-ptr
+    // during a coercion.
+    let x: *const S = &S;
+    let y: *const T = x;  //~ ERROR mismatched types
+
+    let x: *mut S = &mut S;
+    let y: *mut T = x;  //~ ERROR mismatched types
+
+    let x: *const Foo<S> = &Foo {f: S};
+    let y: *const Foo<T> = x;  //~ ERROR mismatched types
+
+    let x: *mut Foo<S> = &mut Foo {f: S};
+    let y: *mut Foo<T> = x;  //~ ERROR mismatched types
+}

src/test/run-fail/dst-raw-slice.rs

@@ -0,0 +1,19 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test bounds checking for DST raw slices
+// error-pattern:index out of bounds
+
+fn main() {
+    let a: *const [_] = &[1i, 2, 3];
+    unsafe {
+        let _b = (*a)[3];
+    }
+}

src/test/run-pass/dst-coercions.rs

@@ -8,21 +8,27 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// Test coercions involving DST and/or raw pointers
+
 struct S;
 trait T {}
 impl T for S {}
 
 pub fn main() {
     let x: &T = &S;
+    // Test we can convert from &-ptr to *-ptr of trait objects
     let x: *const T = &S;
 
+    // Test we can convert from &-ptr to *-ptr of struct pointer (not DST)
     let x: *const S = &S;
 
+    // As above, but mut
     let x: &mut T = &mut S;
     let x: *mut T = &mut S;
 
     let x: *mut S = &mut S;
 
+    // Test we can chnage the mutability from mut to const.
     let x: &T = &mut S;
     let x: *const T = &mut S;
-}
+}

src/test/run-pass/dst-raw.rs

@@ -23,24 +23,22 @@ impl Trait for A {
     }
 }
 
-pub struct Foo<Sized? T> {
+struct Foo<Sized? T> {
     f: T
 }
 
 pub fn main() {
     // raw trait object
     let x = A { f: 42 };
-    let y: *const A = &x;
-    let z: *const Trait = y;
+    let z: *const Trait = &x;
     let r = unsafe {
         (&*z).foo()
     };
     assert!(r == 42);
 
     // raw DST struct
     let p = Foo {f: A { f: 42 }};
-    let q: *const Foo<A> = &p;
-    let o: *const Foo<Trait> = q;
+    let o: *const Foo<Trait> = &p;
     let r = unsafe {
         (&*o).f.foo()
     };
@@ -51,27 +49,29 @@ pub fn main() {
     unsafe {
         let b = (*a)[2];
         assert!(b == 3);
+        let len = (*a).len();
+        assert!(len == 3);
     }
 
     // raw DST struct with slice
     let c: *const Foo<[_]> = &Foo {f: [1i, 2, 3]};
     unsafe {
         let b = (&*c).f[0];
         assert!(b == 1);
+        let len = (&*c).f.len();
+        assert!(len == 3);
     }
 
     // all of the above with *mut
     let mut x = A { f: 42 };
-    let y: *mut A = &mut x;
-    let z: *mut Trait = y;
+    let z: *mut Trait = &mut x;
     let r = unsafe {
         (&*z).foo()
     };
     assert!(r == 42);
 
     let mut p = Foo {f: A { f: 42 }};
-    let q: *mut Foo<A> = &mut p;
-    let o: *mut Foo<Trait> = q;
+    let o: *mut Foo<Trait> = &mut p;
     let r = unsafe {
         (&*o).f.foo()
     };
@@ -81,11 +81,15 @@ pub fn main() {
     unsafe {
         let b = (*a)[2];
         assert!(b == 3);
+        let len = (*a).len();
+        assert!(len == 3);
     }
 
     let c: *mut Foo<[_]> = &mut Foo {f: [1i, 2, 3]};
     unsafe {
         let b = (&*c).f[0];
         assert!(b == 1);
+        let len = (&*c).f.len();
+        assert!(len == 3);
     }
 }