Auto merge of #54432 - kennytm:rollup, r=kennytm

Rollup of 10 pull requests

Successful merges:

 - #53652 (define copy_within on slices)
 - #54261 (Make `dyn` a keyword in the 2018 edition)
 - #54317 (Implement the dbg!(..) macro)
 - #54323 (rustbuild: drop color handling)
 - #54371 (add -Zui-testing to rustdoc)
 - #54374 (Make 'proc_macro::MultiSpan' public.)
 - #54402 (Use no_default_libraries for all NetBSD flavors)
 - #54412 (add applicability to span_suggestion call)
 - #54413 (Add UI test for deref recursion limit printing twice)
 - #54422 (Simplify slice's first(_mut) and last(_mut) with get)

Author: bors

src/bootstrap/bin/rustc.rs

@@ -291,15 +291,6 @@ fn main() {
         cmd.arg("-Z").arg("verify-llvm-ir");
     }
 
-    let color = match env::var("RUSTC_COLOR") {
-        Ok(s) => usize::from_str(&s).expect("RUSTC_COLOR should be an integer"),
-        Err(_) => 0,
-    };
-
-    if color != 0 {
-        cmd.arg("--color=always");
-    }
-
     if env::var_os("RUSTC_DENY_WARNINGS").is_some() && env::var_os("RUSTC_EXTERNAL_TOOL").is_none()
     {
         cmd.arg("-Dwarnings");

src/bootstrap/compile.rs

@@ -29,7 +29,7 @@ use build_helper::{output, mtime, up_to_date};
 use filetime::FileTime;
 use serde_json;
 
-use util::{exe, libdir, is_dylib, CiEnv};
+use util::{exe, libdir, is_dylib};
 use {Compiler, Mode, GitRepo};
 use native;
 
@@ -1034,29 +1034,6 @@ pub fn add_to_sysroot(builder: &Builder, sysroot_dst: &Path, stamp: &Path) {
     }
 }
 
-// Avoiding a dependency on winapi to keep compile times down
-#[cfg(unix)]
-fn stderr_isatty() -> bool {
-    use libc;
-    unsafe { libc::isatty(libc::STDERR_FILENO) != 0 }
-}
-#[cfg(windows)]
-fn stderr_isatty() -> bool {
-    type DWORD = u32;
-    type BOOL = i32;
-    type HANDLE = *mut u8;
-    const STD_ERROR_HANDLE: DWORD = -12i32 as DWORD;
-    extern "system" {
-        fn GetStdHandle(which: DWORD) -> HANDLE;
-        fn GetConsoleMode(hConsoleHandle: HANDLE, lpMode: *mut DWORD) -> BOOL;
-    }
-    unsafe {
-        let handle = GetStdHandle(STD_ERROR_HANDLE);
-        let mut out = 0;
-        GetConsoleMode(handle, &mut out) != 0
-    }
-}
-
 pub fn run_cargo(builder: &Builder,
                  cargo: &mut Command,
                  tail_args: Vec<String>,
@@ -1218,15 +1195,6 @@ pub fn stream_cargo(
     cargo.arg("--message-format").arg("json")
          .stdout(Stdio::piped());
 
-    if stderr_isatty() && builder.ci_env == CiEnv::None &&
-        // if the terminal is reported as dumb, then we don't want to enable color for rustc
-        env::var_os("TERM").map(|t| t != *"dumb").unwrap_or(true) {
-        // since we pass message-format=json to cargo, we need to tell the rustc
-        // wrapper to give us colored output if necessary. This is because we
-        // only want Cargo's JSON output, not rustcs.
-        cargo.env("RUSTC_COLOR", "1");
-    }
-
     for arg in tail_args {
         cargo.arg(arg);
     }

src/libcore/slice/mod.rs

@@ -119,7 +119,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn first(&self) -> Option<&T> {
-        if self.is_empty() { None } else { Some(&self[0]) }
+        self.get(0)
     }
 
     /// Returns a mutable pointer to the first element of the slice, or `None` if it is empty.
@@ -137,7 +137,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn first_mut(&mut self) -> Option<&mut T> {
-        if self.is_empty() { None } else { Some(&mut self[0]) }
+        self.get_mut(0)
     }
 
     /// Returns the first and all the rest of the elements of the slice, or `None` if it is empty.
@@ -239,7 +239,8 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn last(&self) -> Option<&T> {
-        if self.is_empty() { None } else { Some(&self[self.len() - 1]) }
+        let last_idx = self.len().checked_sub(1)?;
+        self.get(last_idx)
     }
 
     /// Returns a mutable pointer to the last item in the slice.
@@ -257,9 +258,8 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn last_mut(&mut self) -> Option<&mut T> {
-        let len = self.len();
-        if len == 0 { return None; }
-        Some(&mut self[len - 1])
+        let last_idx = self.len().checked_sub(1)?;
+        self.get_mut(last_idx)
     }
 
     /// Returns a reference to an element or subslice depending on the type of
@@ -1618,6 +1618,63 @@ impl<T> [T] {
         }
     }
 
+    /// Copies elements from one part of the slice to another part of itself,
+    /// using a memmove.
+    ///
+    /// `src` is the range within `self` to copy from. `dest` is the starting
+    /// index of the range within `self` to copy to, which will have the same
+    /// length as `src`. The two ranges may overlap. The ends of the two ranges
+    /// must be less than or equal to `self.len()`.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if either range exceeds the end of the slice,
+    /// or if the end of `src` is before the start.
+    ///
+    /// # Examples
+    ///
+    /// Copying four bytes within a slice:
+    ///
+    /// ```
+    /// # #![feature(copy_within)]
+    /// let mut bytes = *b"Hello, World!";
+    ///
+    /// bytes.copy_within(1..5, 8);
+    ///
+    /// assert_eq!(&bytes, b"Hello, Wello!");
+    /// ```
+    #[unstable(feature = "copy_within", issue = "54236")]
+    pub fn copy_within<R: ops::RangeBounds<usize>>(&mut self, src: R, dest: usize)
+    where
+        T: Copy,
+    {
+        let src_start = match src.start_bound() {
+            ops::Bound::Included(&n) => n,
+            ops::Bound::Excluded(&n) => n
+                .checked_add(1)
+                .unwrap_or_else(|| slice_index_overflow_fail()),
+            ops::Bound::Unbounded => 0,
+        };
+        let src_end = match src.end_bound() {
+            ops::Bound::Included(&n) => n
+                .checked_add(1)
+                .unwrap_or_else(|| slice_index_overflow_fail()),
+            ops::Bound::Excluded(&n) => n,
+            ops::Bound::Unbounded => self.len(),
+        };
+        assert!(src_start <= src_end, "src end is before src start");
+        assert!(src_end <= self.len(), "src is out of bounds");
+        let count = src_end - src_start;
+        assert!(dest <= self.len() - count, "dest is out of bounds");
+        unsafe {
+            ptr::copy(
+                self.get_unchecked(src_start),
+                self.get_unchecked_mut(dest),
+                count,
+            );
+        }
+    }
+
     /// Swaps all elements in `self` with those in `other`.
     ///
     /// The length of `other` must be the same as `self`.

src/libcore/tests/lib.rs

@@ -39,6 +39,7 @@
 #![feature(inner_deref)]
 #![feature(slice_internals)]
 #![feature(option_replace)]
+#![feature(copy_within)]
 
 extern crate core;
 extern crate test;

src/libcore/tests/slice.rs

@@ -1000,3 +1000,49 @@ fn test_align_to_empty_mid() {
         assert_eq!(mid.as_ptr() as usize % mem::align_of::<Chunk>(), 0);
     }
 }
+
+#[test]
+fn test_copy_within() {
+    // Start to end, with a RangeTo.
+    let mut bytes = *b"Hello, World!";
+    bytes.copy_within(..3, 10);
+    assert_eq!(&bytes, b"Hello, WorHel");
+
+    // End to start, with a RangeFrom.
+    let mut bytes = *b"Hello, World!";
+    bytes.copy_within(10.., 0);
+    assert_eq!(&bytes, b"ld!lo, World!");
+
+    // Overlapping, with a RangeInclusive.
+    let mut bytes = *b"Hello, World!";
+    bytes.copy_within(0..=11, 1);
+    assert_eq!(&bytes, b"HHello, World");
+
+    // Whole slice, with a RangeFull.
+    let mut bytes = *b"Hello, World!";
+    bytes.copy_within(.., 0);
+    assert_eq!(&bytes, b"Hello, World!");
+}
+
+#[test]
+#[should_panic(expected = "src is out of bounds")]
+fn test_copy_within_panics_src_too_long() {
+    let mut bytes = *b"Hello, World!";
+    // The length is only 13, so 14 is out of bounds.
+    bytes.copy_within(10..14, 0);
+}
+
+#[test]
+#[should_panic(expected = "dest is out of bounds")]
+fn test_copy_within_panics_dest_too_long() {
+    let mut bytes = *b"Hello, World!";
+    // The length is only 13, so a slice of length 4 starting at index 10 is out of bounds.
+    bytes.copy_within(0..4, 10);
+}
+#[test]
+#[should_panic(expected = "src end is before src start")]
+fn test_copy_within_panics_src_inverted() {
+    let mut bytes = *b"Hello, World!";
+    // 2 is greater than 1, so this range is invalid.
+    bytes.copy_within(2..1, 0);
+}

src/libproc_macro/lib.rs

@@ -48,7 +48,7 @@ pub mod rustc;
 mod diagnostic;
 
 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
-pub use diagnostic::{Diagnostic, Level};
+pub use diagnostic::{Diagnostic, Level, MultiSpan};
 
 use std::{ascii, fmt, iter};
 use std::path::PathBuf;

src/librustc_lint/builtin.rs

@@ -1937,8 +1937,7 @@ impl EarlyLintPass for KeywordIdents {
         let next_edition = match cx.sess.edition() {
             Edition::Edition2015 => {
                 match &ident.as_str()[..] {
-                    "async" |
-                    "try" => Edition::Edition2018,
+                    "async" | "try" | "dyn" => Edition::Edition2018,
                     _ => return,
                 }
             }

src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs

@@ -22,6 +22,7 @@ use std::collections::VecDeque;
 use std::fmt;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
+use syntax::errors::Applicability;
 
 mod region_name;
 mod var_name;
@@ -540,14 +541,15 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                             RegionName::Named(name) => format!("{}", name),
                             RegionName::Synthesized(_) => "'_".to_string(),
                         };
-                        diag.span_suggestion(
+                        diag.span_suggestion_with_applicability(
                             span,
                             &format!(
                                 "to allow this impl Trait to capture borrowed data with lifetime \
                                  `{}`, add `{}` as a constraint",
                                 fr_name, suggestable_fr_name,
                             ),
                             format!("{} + {}", snippet, suggestable_fr_name),
+                            Applicability::MachineApplicable,
                         );
                     }
                 }

src/librustc_target/spec/netbsd_base.rs

@@ -29,6 +29,7 @@ pub fn opts() -> TargetOptions {
         executables: true,
         target_family: Some("unix".to_string()),
         linker_is_gnu: true,
+        no_default_libraries: false,
         has_rpath: true,
         pre_link_args: args,
         position_independent_executables: true,

src/librustc_target/spec/x86_64_rumprun_netbsd.rs

@@ -21,7 +21,6 @@ pub fn target() -> TargetResult {
     base.has_rpath = false;
     base.position_independent_executables = false;
     base.disable_redzone = true;
-    base.no_default_libraries = false;
     base.exe_allocation_crate = None;
     base.stack_probes = true;