Auto merge of #26182 - Manishearth:rollup, r=Manishearth

- Successful merges: #26142, #26143, #26145, #26146, #26164, #26174
- Failed merges:

Author: bors

src/doc/trpl/enums.md

@@ -64,3 +64,45 @@ equality yet, but we’ll find out in the [`traits`][traits] section.
 [match]: match.html
 [if-let]: if-let.html
 [traits]: traits.html
+
+# Constructors as functions
+
+An enum’s constructors can also be used like functions. For example:
+
+```rust
+# enum Message {
+# Write(String),
+# }
+let m = Message::Write("Hello, world".to_string());
+```
+
+Is the same as
+
+```rust
+# enum Message {
+# Write(String),
+# }
+fn foo(x: String) -> Message {
+    Message::Write(x)
+}
+
+let x = foo("Hello, world".to_string());
+```
+
+This is not immediately useful to us, but when we get to
+[`closures`][closures], we’ll talk about passing functions as arguments to
+other functions. For example, with [`iterators`][iterators], we can do this
+to convert a vector of `String`s into a vector of `Message::Write`s:
+
+```rust
+# enum Message {
+# Write(String),
+# }
+
+let v = vec!["Hello".to_string(), "World".to_string()];
+
+let v1: Vec<Message> = v.into_iter().map(Message::Write).collect();
+```
+
+[closures]: closures.html
+[iterators]: iterators.html

src/doc/trpl/ffi.md

@@ -238,7 +238,7 @@ However it is often desired that the callback is targeted to a special
 Rust object. This could be the object that represents the wrapper for the
 respective C object.
 
-This can be achieved by passing an unsafe pointer to the object down to the
+This can be achieved by passing an raw pointer to the object down to the
 C library. The C library can then include the pointer to the Rust object in
 the notification. This will allow the callback to unsafely access the
 referenced Rust object.
@@ -370,7 +370,7 @@ On OSX, frameworks behave with the same semantics as a dynamic library.
 
 # Unsafe blocks
 
-Some operations, like dereferencing unsafe pointers or calling functions that have been marked
+Some operations, like dereferencing raw pointers or calling functions that have been marked
 unsafe are only allowed inside unsafe blocks. Unsafe blocks isolate unsafety and are a promise to
 the compiler that the unsafety does not leak out of the block.
 

src/doc/trpl/functions.md

@@ -144,7 +144,9 @@ an expression, and a `let` can only begin a statement, not an expression.
 Note that assigning to an already-bound variable (e.g. `y = 5`) is still an
 expression, although its value is not particularly useful. Unlike other
 languages where an assignment evaluates to the assigned value (e.g. `5` in the
-previous example), in Rust the value of an assignment is an empty tuple `()`:
+previous example), in Rust the value of an assignment is an empty tuple `()`
+because the assigned value can have [just one owner](ownership.html), and any
+other returned value would be too surprising:
 
 ```rust
 let mut y = 5;

src/doc/trpl/raw-pointers.md

@@ -52,9 +52,9 @@ println!("raw points at {}", *raw);
 It gives this error:
 
 ```text
-error: dereference of unsafe pointer requires unsafe function or block [E0133]
-     println!("raw points at{}", *raw);
-                                 ^~~~
+error: dereference of raw pointer requires unsafe function or block [E0133]
+     println!("raw points at {}", *raw);
+                                  ^~~~
 ```
 
 When you dereference a raw pointer, you’re taking responsibility that it’s not

src/doc/trpl/strings.md

@@ -117,6 +117,30 @@ let dog = hachiko.chars().nth(1); // kinda like hachiko[1]
 
 This emphasizes that we have to go through the whole list of `chars`.
 
+## Slicing
+
+You can get a slice of a string with slicing syntax:
+
+```rust
+let dog = "hachiko";
+let hachi = &dog[0..5];
+```
+
+But note that these are _byte_ offsets, not _character_ offsets. So
+this will fail at runtime:
+
+```rust,should_panic
+let dog = "忠犬ハチ公";
+let hachi = &dog[0..2];
+```
+
+with this error:
+
+```text
+thread '<main>' panicked at 'index 0 and/or 2 in `忠犬ハチ公` do not lie on
+character boundary'
+```
+
 ## Concatenation
 
 If you have a `String`, you can concatenate a `&str` to the end of it:

src/liballoc/lib.rs

@@ -22,9 +22,9 @@
 //!
 //! ## Boxed values
 //!
-//! The [`Box`](boxed/index.html) type is the core owned pointer type in Rust.
-//! There can only be one owner of a `Box`, and the owner can decide to mutate
-//! the contents, which live on the heap.
+//! The [`Box`](boxed/index.html) type is a smart pointer type. There can
+//! only be one owner of a `Box`, and the owner can decide to mutate the
+//! contents, which live on the heap.
 //!
 //! This type can be sent among threads efficiently as the size of a `Box` value
 //! is the same as that of a pointer. Tree-like data structures are often built

src/libcollections/slice.rs

@@ -370,7 +370,7 @@ impl<T> [T] {
         core_slice::SliceExt::get_unchecked_mut(self, index)
     }
 
-    /// Returns an unsafe pointer to the slice's buffer
+    /// Returns an raw pointer to the slice's buffer
     ///
     /// The caller must ensure that the slice outlives the pointer this
     /// function returns, or else it will end up pointing to garbage.

src/libcollections/str.rs

@@ -525,7 +525,7 @@ impl str {
         core_str::StrExt::as_bytes(&self[..])
     }
 
-    /// Returns an unsafe pointer to the `&str`'s buffer.
+    /// Returns a raw pointer to the `&str`'s buffer.
     ///
     /// The caller must ensure that the string outlives this pointer, and
     /// that it is not

src/libcollections/vec.rs

@@ -1213,9 +1213,9 @@ impl<T: PartialEq> Vec<T> {
             // Duplicate, advance r. End of vec. Truncate to w.
 
             let ln = self.len();
-            if ln < 1 { return; }
+            if ln <= 1 { return; }
 
-            // Avoid bounds checks by using unsafe pointers.
+            // Avoid bounds checks by using raw pointers.
             let p = self.as_mut_ptr();
             let mut r: usize = 1;
             let mut w: usize = 1;

src/libcore/intrinsics.rs

@@ -46,7 +46,7 @@ use marker::Sized;
 
 extern "rust-intrinsic" {
 
-    // NB: These intrinsics take unsafe pointers because they mutate aliased
+    // NB: These intrinsics take raw pointers because they mutate aliased
     // memory, which is not valid for either `&` or `&mut`.
 
     pub fn atomic_cxchg<T>(dst: *mut T, old: T, src: T) -> T;