Auto merge of #66208 - JohnTitor:rollup-2umgjer, r=JohnTitor

Rollup of 8 pull requests

Successful merges:

 - #65554 (Enhance the documentation of BufReader for potential data loss)
 - #65580 (Add `MaybeUninit` methods `uninit_array`, `slice_get_ref`, `slice_get_mut`)
 - #66049 (consistent handling of missing sysroot spans)
 - #66056 (rustc_metadata: Some reorganization of the module structure)
 - #66123 (No more hidden elements)
 - #66157 (Improve math log documentation examples)
 - #66165 (Ignore these tests ,since the called commands doesn't exist in VxWorks)
 - #66190 (rustc_target: inline abi::FloatTy into abi::Primitive.)

Failed merges:

 - #66188 (`MethodSig` -> `FnSig` & Use it in `ItemKind::Fn`)

r? @ghost

3 files changed, 31 insertions, 23 deletions

diff --git a/src/libstd/f64.rs b/src/libstd/f64.rs
index 44d25f1b476..0588373dcdc 100644
--- a/src/libstd/f64.rs
+++ b/src/libstd/f64.rs
@@ -409,10 +409,10 @@ impl f64 {
     /// # Examples
     ///
     /// ```
-    /// let five = 5.0_f64;
+    /// let twenty_five = 25.0_f64;
     ///
-    /// // log5(5) - 1 == 0
-    /// let abs_difference = (five.log(5.0) - 1.0).abs();
+    /// // log5(25) - 2 == 0
+    /// let abs_difference = (twenty_five.log(5.0) - 2.0).abs();
     ///
     /// assert!(abs_difference < 1e-10);
     /// ```
@@ -425,10 +425,10 @@ impl f64 {
     /// # Examples
     ///
     /// ```
-    /// let two = 2.0_f64;
+    /// let four = 4.0_f64;
     ///
-    /// // log2(2) - 1 == 0
-    /// let abs_difference = (two.log2() - 1.0).abs();
+    /// // log2(4) - 2 == 0
+    /// let abs_difference = (four.log2() - 2.0).abs();
     ///
     /// assert!(abs_difference < 1e-10);
     /// ```
@@ -448,10 +448,10 @@ impl f64 {
     /// # Examples
     ///
     /// ```
-    /// let ten = 10.0_f64;
+    /// let hundred = 100.0_f64;
     ///
-    /// // log10(10) - 1 == 0
-    /// let abs_difference = (ten.log10() - 1.0).abs();
+    /// // log10(100) - 2 == 0
+    /// let abs_difference = (hundred.log10() - 2.0).abs();
     ///
     /// assert!(abs_difference < 1e-10);
     /// ```
diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 9593a1bae0a..ad567c97c2c 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -24,7 +24,9 @@ use crate::memchr;
 ///
 /// When the `BufReader<R>` is dropped, the contents of its buffer will be
 /// discarded. Creating multiple instances of a `BufReader<R>` on the same
-/// stream can cause data loss.
+/// stream can cause data loss. Reading from the underlying reader after
+/// unwrapping the `BufReader<R>` with `BufReader::into_inner` can also cause
+/// data loss.
 ///
 /// [`Read`]: ../../std/io/trait.Read.html
 /// [`TcpStream::read`]: ../../std/net/struct.TcpStream.html#method.read
@@ -179,7 +181,8 @@ impl<R> BufReader<R> {
 
     /// Unwraps this `BufReader<R>`, returning the underlying reader.
     ///
-    /// Note that any leftover data in the internal buffer is lost.
+    /// Note that any leftover data in the internal buffer is lost. Therefore,
+    /// a following read from the underlying reader may lead to data loss.
     ///
     /// # Examples
     ///
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index 4b0cf8312f1..b1274a08cbe 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -1661,7 +1661,7 @@ mod tests {
     // FIXME(#10380) these tests should not all be ignored on android.
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn smoke() {
         let p = if cfg!(target_os = "windows") {
             Command::new("cmd").args(&["/C", "exit 0"]).spawn()
@@ -1683,7 +1683,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn exit_reported_right() {
         let p = if cfg!(target_os = "windows") {
             Command::new("cmd").args(&["/C", "exit 1"]).spawn()
@@ -1698,7 +1698,7 @@ mod tests {
 
     #[test]
     #[cfg(unix)]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn signal_reported_right() {
         use crate::os::unix::process::ExitStatusExt;
 
@@ -1726,7 +1726,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn stdout_works() {
         if cfg!(target_os = "windows") {
             let mut cmd = Command::new("cmd");
@@ -1740,7 +1740,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(any(windows, target_os = "android"), ignore)]
+    #[cfg_attr(any(windows, target_os = "android", target_os = "vxworks"), ignore)]
     fn set_current_dir_works() {
         let mut cmd = Command::new("/bin/sh");
         cmd.arg("-c").arg("pwd")
@@ -1750,7 +1750,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(any(windows, target_os = "android"), ignore)]
+    #[cfg_attr(any(windows, target_os = "android", target_os = "vxworks"), ignore)]
     fn stdin_works() {
         let mut p = Command::new("/bin/sh")
                             .arg("-c").arg("read line; echo $line")
@@ -1766,7 +1766,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn test_process_status() {
         let mut status = if cfg!(target_os = "windows") {
             Command::new("cmd").args(&["/C", "exit 1"]).status().unwrap()
@@ -1792,7 +1792,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn test_process_output_output() {
         let Output {status, stdout, stderr}
              = if cfg!(target_os = "windows") {
@@ -1808,7 +1808,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn test_process_output_error() {
         let Output {status, stdout, stderr}
              = if cfg!(target_os = "windows") {
@@ -1823,7 +1823,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn test_finish_once() {
         let mut prog = if cfg!(target_os = "windows") {
             Command::new("cmd").args(&["/C", "exit 1"]).spawn().unwrap()
@@ -1834,7 +1834,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn test_finish_twice() {
         let mut prog = if cfg!(target_os = "windows") {
             Command::new("cmd").args(&["/C", "exit 1"]).spawn().unwrap()
@@ -1846,7 +1846,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg_attr(target_os = "android", ignore)]
+    #[cfg_attr(any(target_os = "vxworks", target_os = "android"), ignore)]
     fn test_wait_with_output_once() {
         let prog = if cfg!(target_os = "windows") {
             Command::new("cmd").args(&["/C", "echo hello"]).stdout(Stdio::piped()).spawn().unwrap()
@@ -1881,6 +1881,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "vxworks", ignore)]
     fn test_override_env() {
         use crate::env;
 
@@ -1901,6 +1902,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "vxworks", ignore)]
     fn test_add_to_env() {
         let result = env_cmd().env("RUN_TEST_NEW_ENV", "123").output().unwrap();
         let output = String::from_utf8_lossy(&result.stdout).to_string();
@@ -1910,6 +1912,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "vxworks", ignore)]
     fn test_capture_env_at_spawn() {
         use crate::env;
 
@@ -1965,6 +1968,7 @@ mod tests {
 
     // Regression tests for #30862.
     #[test]
+    #[cfg_attr(target_os = "vxworks", ignore)]
     fn test_interior_nul_in_env_key_is_error() {
         match env_cmd().env("has-some-\0\0s-inside", "value").spawn() {
             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),
@@ -1973,6 +1977,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "vxworks", ignore)]
     fn test_interior_nul_in_env_value_is_error() {
         match env_cmd().env("key", "has-some-\0\0s-inside").spawn() {
             Err(e) => assert_eq!(e.kind(), ErrorKind::InvalidInput),