Rollup of 4 pull requests

src/librustc_driver/lib.rs

@@ -83,10 +83,11 @@ use std::cmp::max;
 use std::cmp::Ordering::Equal;
 use std::default::Default;
 use std::env;
+use std::ffi::OsString;
 use std::io::{self, Read, Write};
 use std::iter::repeat;
 use std::path::PathBuf;
-use std::process;
+use std::process::{self, Command, Stdio};
 use std::rc::Rc;
 use std::str;
 use std::sync::{Arc, Mutex};
@@ -356,27 +357,65 @@ fn handle_explain(code: &str,
     match descriptions.find_description(&normalised) {
         Some(ref description) => {
             let mut is_in_code_block = false;
+            let mut text = String::new();
+
             // Slice off the leading newline and print.
             for line in description[1..].lines() {
                 let indent_level = line.find(|c: char| !c.is_whitespace())
                     .unwrap_or_else(|| line.len());
                 let dedented_line = &line[indent_level..];
                 if dedented_line.starts_with("```") {
                     is_in_code_block = !is_in_code_block;
-                    println!("{}", &line[..(indent_level+3)]);
+                    text.push_str(&line[..(indent_level+3)]);
                 } else if is_in_code_block && dedented_line.starts_with("# ") {
                     continue;
                 } else {
-                    println!("{}", line);
+                    text.push_str(line);
                 }
+                text.push('\n');
             }
+
+            show_content_with_pager(&text);
         }
         None => {
             early_error(output, &format!("no extended information for {}", code));
         }
     }
 }
 
+fn show_content_with_pager(content: &String) {
+    let pager_name = env::var_os("PAGER").unwrap_or_else(|| if cfg!(windows) {
+        OsString::from("more.com")
+    } else {
+        OsString::from("less")
+    });
+
+    let mut fallback_to_println = false;
+
+    match Command::new(pager_name).stdin(Stdio::piped()).spawn() {
+        Ok(mut pager) => {
+            if let Some(mut pipe) = pager.stdin.as_mut() {
+                if pipe.write_all(content.as_bytes()).is_err() {
+                    fallback_to_println = true;
+                }
+            }
+
+            if pager.wait().is_err() {
+                fallback_to_println = true;
+            }
+        }
+        Err(_) => {
+            fallback_to_println = true;
+        }
+    }
+
+    // If pager fails for whatever reason, we should still print the content
+    // to standard output
+    if fallback_to_println {
+        print!("{}", content);
+    }
+}
+
 impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
     fn early_callback(&mut self,
                       matches: &getopts::Matches,

src/librustc_typeck/check/intrinsic.rs

@@ -37,7 +37,7 @@ fn equate_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     match it.node {
         hir::ForeignItemFn(..) => {}
         _ => {
-            struct_span_err!(tcx.sess, it.span, E0619,
+            struct_span_err!(tcx.sess, it.span, E0621,
                              "intrinsic must be a function")
                 .span_label(it.span, "expected a function")
                 .emit();

src/librustc_typeck/diagnostics.rs

@@ -4726,6 +4726,26 @@ let x = &[1_usize, 2] as &[usize]; // ok!
 ```
 "##,
 
+E0621: r##"
+An intrinsic was declared without being a function.
+
+Erroneous code example:
+
+```compile_fail,E0621
+#![feature(intrinsics)]
+extern "rust-intrinsic" {
+    pub static breakpoint : unsafe extern "rust-intrinsic" fn();
+    // error: intrinsic must be a function
+}
+
+fn main() { unsafe { breakpoint(); } }
+```
+
+An intrinsic is a function available for use in a given programming language
+whose implementation is handled specially by the compiler. In order to fix this
+error, just declare a function.
+"##,
+
 }
 
 register_diagnostics! {

src/libstd/fs.rs

@@ -653,15 +653,29 @@ impl OpenOptions {
     /// # Errors
     ///
     /// This function will return an error under a number of different
-    /// circumstances, to include but not limited to:
-    ///
-    /// * Opening a file that does not exist without setting `create` or
-    ///   `create_new`.
-    /// * Attempting to open a file with access that the user lacks
-    ///   permissions for
-    /// * Filesystem-level errors (full disk, etc)
-    /// * Invalid combinations of open options (truncate without write access,
-    ///   no access mode set, etc)
+    /// circumstances. Some of these error conditions are listed here, together
+    /// with their [`ErrorKind`]. The mapping to [`ErrorKind`]s is not part of
+    /// the compatiblity contract of the function, especially the `Other` kind
+    /// might change to more specific kinds in the future.
+    ///
+    /// * [`NotFound`]: The specified file does not exist and neither `create`
+    ///   or `create_new` is set.
+    /// * [`NotFound`]: One of the directory components of the file path does
+    ///   not exist.
+    /// * [`PermissionDenied`]: The user lacks permission to get the specified
+    ///   access rights for the file.
+    /// * [`PermissionDenied`]: The user lacks permission to open one of the
+    ///   directory components of the specified path.
+    /// * [`AlreadyExists`]: `create_new` was specified and the file already
+    ///   exists.
+    /// * [`InvalidInput`]: Invalid combinations of open options (truncate
+    ///   without write access, no access mode set, etc.).
+    /// * [`Other`]: One of the directory components of the specified file path
+    ///   was not, in fact, a directory.
+    /// * [`Other`]: Filesystem-level errors: full disk, write permission
+    ///   requested on a read-only file system, exceeded disk quota, too many
+    ///   open files, too long filename, too many symbolic links in the
+    ///   specified path (Unix-like systems only), etc.
     ///
     /// # Examples
     ///
@@ -670,6 +684,13 @@ impl OpenOptions {
     ///
     /// let file = OpenOptions::new().open("foo.txt");
     /// ```
+    ///
+    /// [`ErrorKind`]: ../io/enum.ErrorKind.html
+    /// [`AlreadyExists`]: ../io/enum.ErrorKind.html#variant.AlreadyExists
+    /// [`InvalidInput`]: ../io/enum.ErrorKind.html#variant.InvalidInput
+    /// [`NotFound`]: ../io/enum.ErrorKind.html#variant.NotFound
+    /// [`Other`]: ../io/enum.ErrorKind.html#variant.Other
+    /// [`PermissionDenied`]: ../io/enum.ErrorKind.html#variant.PermissionDenied
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn open<P: AsRef<Path>>(&self, path: P) -> io::Result<File> {
         self._open(path.as_ref())

src/test/compile-fail/E0619.rs

@@ -16,3 +16,4 @@ fn main() {
         _ => {}
     }
 }
+

src/test/compile-fail/invalid-intrinsic.rs → src/test/compile-fail/E0621.rs

@@ -11,6 +11,6 @@
 #![feature(intrinsics)]
 extern "rust-intrinsic" {
     pub static breakpoint : unsafe extern "rust-intrinsic" fn();
-    //~^ ERROR intrinsic must be a function
+    //~^ ERROR intrinsic must be a function [E0621]
 }
 fn main() { unsafe { breakpoint(); } }