auto merge of #18645 : nick29581/rust/coercions-1, r=alexcrichton

r?

(I realise this needs a rebase, but I will probably have to chop it up in order to land and I'd like to get r+ first so I can do that quicker)

Author: bors

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

@@ -93,27 +93,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                a.repr(self.get_ref().infcx.tcx),
                b.repr(self.get_ref().infcx.tcx));
 
-        // Special case: if the subtype is a sized array literal (`[T, ..n]`),
-        // then it would get auto-borrowed to `&[T, ..n]` and then DST-ified
-        // to `&[T]`. Doing it all at once makes the target code a bit more
-        // efficient and spares us from having to handle multiple coercions.
-        match ty::get(b).sty {
-            ty::ty_ptr(mt_b) | ty::ty_rptr(_, mt_b) => {
-                match ty::get(mt_b.ty).sty {
-                    ty::ty_vec(_, None) => {
-                        let unsize_and_ref = self.unpack_actual_value(a, |sty_a| {
-                            self.coerce_unsized_with_borrow(a, sty_a, b, mt_b.mutbl)
-                        });
-                        if unsize_and_ref.is_ok() {
-                            return unsize_and_ref;
-                        }
-                    }
-                    _ => {}
-                }
-            }
-            _ => {}
-        }
-
         // Consider coercing the subtype to a DST
         let unsize = self.unpack_actual_value(a, |sty_a| {
             self.coerce_unsized(a, sty_a, b)
@@ -274,35 +253,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
         })))
     }
 
-    // [T, ..n] -> &[T] or &mut [T]
-    fn coerce_unsized_with_borrow(&self,
-                                  a: ty::t,
-                                  sty_a: &ty::sty,
-                                  b: ty::t,
-                                  mutbl_b: ast::Mutability)
-                                  -> CoerceResult {
-        debug!("coerce_unsized_with_borrow(a={}, sty_a={}, b={})",
-               a.repr(self.get_ref().infcx.tcx), sty_a,
-               b.repr(self.get_ref().infcx.tcx));
-
-        match *sty_a {
-            ty::ty_vec(t_a, Some(len)) => {
-                let sub = Sub(self.get_ref().clone());
-                let coercion = Coercion(self.get_ref().trace.clone());
-                let r_borrow = self.get_ref().infcx.next_region_var(coercion);
-                let unsized_ty = ty::mk_slice(self.get_ref().infcx.tcx, r_borrow,
-                                              mt {ty: t_a, mutbl: mutbl_b});
-                try!(self.get_ref().infcx.try(|| sub.tys(unsized_ty, b)));
-                Ok(Some(AdjustDerefRef(AutoDerefRef {
-                    autoderefs: 0,
-                    autoref: Some(ty::AutoPtr(r_borrow,
-                                              mutbl_b,
-                                              Some(box AutoUnsize(ty::UnsizeLength(len)))))
-                })))
-            }
-            _ => Err(ty::terr_mismatch)
-        }
-    }
 
     // &[T, ..n] or &mut [T, ..n] -> &[T]
     // or &mut [T, ..n] -> &mut [T]

src/libstd/os.rs

@@ -140,7 +140,7 @@ pub fn getcwd() -> Path {
             panic!();
         }
     }
-    Path::new(String::from_utf16(::str::truncate_utf16_at_nul(buf))
+    Path::new(String::from_utf16(::str::truncate_utf16_at_nul(&buf))
               .expect("GetCurrentDirectoryW returned invalid UTF-16"))
 }
 
@@ -2065,12 +2065,12 @@ mod tests {
             join_paths(input).unwrap().as_slice() == output.as_bytes()
         }
 
-        assert!(test_eq([], ""));
-        assert!(test_eq([r"c:\windows", r"c:\"],
+        assert!(test_eq(&[], ""));
+        assert!(test_eq(&[r"c:\windows", r"c:\"],
                         r"c:\windows;c:\"));
-        assert!(test_eq(["", r"c:\windows", "", "", r"c:\", ""],
+        assert!(test_eq(&["", r"c:\windows", "", "", r"c:\", ""],
                         r";c:\windows;;;c:\;"));
-        assert!(test_eq([r"c:\te;st", r"c:\"],
+        assert!(test_eq(&[r"c:\te;st", r"c:\"],
                         r#""c:\te;st";c:\"#));
         assert!(join_paths(&[r#"c:\te"st"#]).is_err());
     }

src/libstd/rand/os.rs

@@ -298,12 +298,12 @@ mod imp {
     impl Rng for OsRng {
         fn next_u32(&mut self) -> u32 {
             let mut v = [0u8, .. 4];
-            self.fill_bytes(v);
+            self.fill_bytes(&mut v);
             unsafe { mem::transmute(v) }
         }
         fn next_u64(&mut self) -> u64 {
             let mut v = [0u8, .. 8];
-            self.fill_bytes(v);
+            self.fill_bytes(&mut v);
             unsafe { mem::transmute(v) }
         }
         fn fill_bytes(&mut self, v: &mut [u8]) {

src/libstd/rt/backtrace.rs

@@ -999,7 +999,7 @@ mod imp {
                     None => try!(w.write(bytes[..bytes.len()-1])),
                 }
             }
-            try!(w.write(['\n' as u8]));
+            try!(w.write(&['\n' as u8]));
         }
 
         Ok(())

src/libstd/sys/windows/fs.rs

@@ -263,7 +263,7 @@ pub fn readdir(p: &Path) -> IoResult<Vec<Path>> {
             let mut more_files = 1 as libc::BOOL;
             while more_files != 0 {
                 {
-                    let filename = str::truncate_utf16_at_nul(wfd.cFileName);
+                    let filename = str::truncate_utf16_at_nul(&wfd.cFileName);
                     match String::from_utf16(filename) {
                         Some(filename) => paths.push(Path::new(filename)),
                         None => {

src/libstd/sys/windows/os.rs

@@ -76,7 +76,7 @@ pub fn error_string(errnum: i32) -> String {
             return format!("OS Error {} (FormatMessageW() returned error {})", errnum, fm_err);
         }
 
-        let msg = String::from_utf16(::str::truncate_utf16_at_nul(buf));
+        let msg = String::from_utf16(::str::truncate_utf16_at_nul(&buf));
         match msg {
             Some(msg) => format!("OS Error {}: {}", errnum, msg),
             None => format!("OS Error {} (FormatMessageW() returned invalid UTF-16)", errnum),

src/libstd/sys/windows/pipe.rs

@@ -395,7 +395,7 @@ impl UnixStream {
         loop {
             // Process a timeout if one is pending
             let wait_succeeded = await(self.handle(), self.read_deadline,
-                                       [overlapped.hEvent]);
+                                       &[overlapped.hEvent]);
 
             let ret = unsafe {
                 libc::GetOverlappedResult(self.handle(),
@@ -459,7 +459,7 @@ impl UnixStream {
                 }
                 // Process a timeout if one is pending
                 let wait_succeeded = await(self.handle(), self.write_deadline,
-                                           [overlapped.hEvent]);
+                                           &[overlapped.hEvent]);
                 let ret = unsafe {
                     libc::GetOverlappedResult(self.handle(),
                                               &mut overlapped,
@@ -660,8 +660,8 @@ impl UnixAcceptor {
             if err == libc::ERROR_IO_PENDING as libc::DWORD {
                 // Process a timeout if one is pending
                 let wait_succeeded = await(handle, self.deadline,
-                                           [self.inner.abort.handle(),
-                                            overlapped.hEvent]);
+                                           &[self.inner.abort.handle(),
+                                             overlapped.hEvent]);
 
                 // This will block until the overlapped I/O is completed. The
                 // timeout was previously handled, so this will either block in

src/libstd/sys/windows/process.rs

@@ -487,24 +487,24 @@ mod tests {
         }
 
         assert_eq!(
-            test_wrapper("prog", ["aaa", "bbb", "ccc"]),
+            test_wrapper("prog", &["aaa", "bbb", "ccc"]),
             "prog aaa bbb ccc".to_string()
         );
 
         assert_eq!(
-            test_wrapper("C:\\Program Files\\blah\\blah.exe", ["aaa"]),
+            test_wrapper("C:\\Program Files\\blah\\blah.exe", &["aaa"]),
             "\"C:\\Program Files\\blah\\blah.exe\" aaa".to_string()
         );
         assert_eq!(
-            test_wrapper("C:\\Program Files\\test", ["aa\"bb"]),
+            test_wrapper("C:\\Program Files\\test", &["aa\"bb"]),
             "\"C:\\Program Files\\test\" aa\\\"bb".to_string()
         );
         assert_eq!(
-            test_wrapper("echo", ["a b c"]),
+            test_wrapper("echo", &["a b c"]),
             "echo \"a b c\"".to_string()
         );
         assert_eq!(
-            test_wrapper("\u03c0\u042f\u97f3\u00e6\u221e", []),
+            test_wrapper("\u03c0\u042f\u97f3\u00e6\u221e", &[]),
             "\u03c0\u042f\u97f3\u00e6\u221e".to_string()
         );
     }

src/test/compile-fail/coercion-slice.rs

@@ -0,0 +1,15 @@
+// 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.
+
+// Tests that we forbid coercion from `[T, ..n]` to `&[T]`
+
+fn main() {
+    let _: &[int] = [0i]; //~ERROR: mismatched types: expected `&[int]`, found `[int, ..1]`
+}

src/test/run-pass/tcp-stress.rs

@@ -45,7 +45,7 @@ fn main() {
                 }
             };
             stream.read_byte();
-            stream.write([2]);
+            stream.write(&[2]);
         }
     });
     let addr = rx.recv();
@@ -57,9 +57,9 @@ fn main() {
             match TcpStream::connect(addr) {
                 Ok(stream) => {
                     let mut stream = stream;
-                    stream.write([1]);
+                    stream.write(&[1]);
                     let mut buf = [0];
-                    stream.read(buf);
+                    stream.read(&mut buf);
                 },
                 Err(e) => debug!("{}", e)
             }