Auto merge of #53354 - kennytm:rollup, r=kennytm

Rollup of 11 pull requests

Successful merges:

 - #53112 (pretty print BTreeSet)
 - #53208 (Don't panic on std::env::vars() when env is null.)
 - #53226 (driver: set the syntax edition in phase 1)
 - #53229 (Make sure rlimit is only ever increased)
 - #53233 (targets: aarch64: Add bare-metal aarch64 target)
 - #53239 (rustc_codegen_llvm: Restore the closure env alloca hack for LLVM 5.)
 - #53246 (A few cleanups)
 - #53257 (Idiomatic improvements to IP method)
 - #53274 (Remove statics field from CodegenCx)
 - #53290 (Make LLVM emit assembly comments with -Z asm-comments)
 - #53317 (Mark prior failure to avoid ICE)

2 files changed, 51 insertions, 52 deletions

diff --git a/src/libstd/net/ip.rs b/src/libstd/net/ip.rs
index d601a0c42e9..9a610cd7d6b 100644
--- a/src/libstd/net/ip.rs
+++ b/src/libstd/net/ip.rs
@@ -160,9 +160,9 @@ impl IpAddr {
     /// ```
     #[stable(feature = "ip_shared", since = "1.12.0")]
     pub fn is_unspecified(&self) -> bool {
-        match *self {
-            IpAddr::V4(ref a) => a.is_unspecified(),
-            IpAddr::V6(ref a) => a.is_unspecified(),
+        match self {
+            IpAddr::V4(ip) => ip.is_unspecified(),
+            IpAddr::V6(ip) => ip.is_unspecified(),
         }
     }
 
@@ -185,9 +185,9 @@ impl IpAddr {
     /// ```
     #[stable(feature = "ip_shared", since = "1.12.0")]
     pub fn is_loopback(&self) -> bool {
-        match *self {
-            IpAddr::V4(ref a) => a.is_loopback(),
-            IpAddr::V6(ref a) => a.is_loopback(),
+        match self {
+            IpAddr::V4(ip) => ip.is_loopback(),
+            IpAddr::V6(ip) => ip.is_loopback(),
         }
     }
 
@@ -214,9 +214,9 @@ impl IpAddr {
     /// }
     /// ```
     pub fn is_global(&self) -> bool {
-        match *self {
-            IpAddr::V4(ref a) => a.is_global(),
-            IpAddr::V6(ref a) => a.is_global(),
+        match self {
+            IpAddr::V4(ip) => ip.is_global(),
+            IpAddr::V6(ip) => ip.is_global(),
         }
     }
 
@@ -239,9 +239,9 @@ impl IpAddr {
     /// ```
     #[stable(feature = "ip_shared", since = "1.12.0")]
     pub fn is_multicast(&self) -> bool {
-        match *self {
-            IpAddr::V4(ref a) => a.is_multicast(),
-            IpAddr::V6(ref a) => a.is_multicast(),
+        match self {
+            IpAddr::V4(ip) => ip.is_multicast(),
+            IpAddr::V6(ip) => ip.is_multicast(),
         }
     }
 
@@ -268,9 +268,9 @@ impl IpAddr {
     /// }
     /// ```
     pub fn is_documentation(&self) -> bool {
-        match *self {
-            IpAddr::V4(ref a) => a.is_documentation(),
-            IpAddr::V6(ref a) => a.is_documentation(),
+        match self {
+            IpAddr::V4(ip) => ip.is_documentation(),
+            IpAddr::V6(ip) => ip.is_documentation(),
         }
     }
 
@@ -293,7 +293,7 @@ impl IpAddr {
     /// ```
     #[stable(feature = "ipaddr_checker", since = "1.16.0")]
     pub fn is_ipv4(&self) -> bool {
-        match *self {
+        match self {
             IpAddr::V4(_) => true,
             IpAddr::V6(_) => false,
         }
@@ -318,7 +318,7 @@ impl IpAddr {
     /// ```
     #[stable(feature = "ipaddr_checker", since = "1.16.0")]
     pub fn is_ipv6(&self) -> bool {
-        match *self {
+        match self {
             IpAddr::V4(_) => false,
             IpAddr::V6(_) => true,
         }
@@ -483,11 +483,11 @@ impl Ipv4Addr {
     /// ```
     #[stable(since = "1.7.0", feature = "ip_17")]
     pub fn is_private(&self) -> bool {
-        match (self.octets()[0], self.octets()[1]) {
-            (10, _) => true,
-            (172, b) if b >= 16 && b <= 31 => true,
-            (192, 168) => true,
-            _ => false
+        match self.octets() {
+            [10, ..] => true,
+            [172, b, ..] if b >= 16 && b <= 31 => true,
+            [192, 168, ..] => true,
+            _ => false,
         }
     }
 
@@ -509,7 +509,10 @@ impl Ipv4Addr {
     /// ```
     #[stable(since = "1.7.0", feature = "ip_17")]
     pub fn is_link_local(&self) -> bool {
-        self.octets()[0] == 169 && self.octets()[1] == 254
+        match self.octets() {
+            [169, 254, ..] => true,
+            _ => false,
+        }
     }
 
     /// Returns [`true`] if the address appears to be globally routable.
@@ -612,11 +615,11 @@ impl Ipv4Addr {
     /// ```
     #[stable(since = "1.7.0", feature = "ip_17")]
     pub fn is_documentation(&self) -> bool {
-        match(self.octets()[0], self.octets()[1], self.octets()[2], self.octets()[3]) {
-            (192, 0, 2, _) => true,
-            (198, 51, 100, _) => true,
-            (203, 0, 113, _) => true,
-            _ => false
+        match self.octets() {
+            [192, 0, 2, _] => true,
+            [198, 51, 100, _] => true,
+            [203, 0, 113, _] => true,
+            _ => false,
         }
     }
 
@@ -666,9 +669,9 @@ impl Ipv4Addr {
 #[stable(feature = "ip_addr", since = "1.7.0")]
 impl fmt::Display for IpAddr {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            IpAddr::V4(ref a) => a.fmt(fmt),
-            IpAddr::V6(ref a) => a.fmt(fmt),
+        match self {
+            IpAddr::V4(ip) => ip.fmt(fmt),
+            IpAddr::V6(ip) => ip.fmt(fmt),
         }
     }
 }
@@ -717,8 +720,8 @@ impl PartialEq for Ipv4Addr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialEq<Ipv4Addr> for IpAddr {
     fn eq(&self, other: &Ipv4Addr) -> bool {
-        match *self {
-            IpAddr::V4(ref v4) => v4 == other,
+        match self {
+            IpAddr::V4(v4) => v4 == other,
             IpAddr::V6(_) => false,
         }
     }
@@ -727,8 +730,8 @@ impl PartialEq<Ipv4Addr> for IpAddr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialEq<IpAddr> for Ipv4Addr {
     fn eq(&self, other: &IpAddr) -> bool {
-        match *other {
-            IpAddr::V4(ref v4) => self == v4,
+        match other {
+            IpAddr::V4(v4) => self == v4,
             IpAddr::V6(_) => false,
         }
     }
@@ -755,8 +758,8 @@ impl PartialOrd for Ipv4Addr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialOrd<Ipv4Addr> for IpAddr {
     fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering> {
-        match *self {
-            IpAddr::V4(ref v4) => v4.partial_cmp(other),
+        match self {
+            IpAddr::V4(v4) => v4.partial_cmp(other),
             IpAddr::V6(_) => Some(Ordering::Greater),
         }
     }
@@ -765,8 +768,8 @@ impl PartialOrd<Ipv4Addr> for IpAddr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialOrd<IpAddr> for Ipv4Addr {
     fn partial_cmp(&self, other: &IpAddr) -> Option<Ordering> {
-        match *other {
-            IpAddr::V4(ref v4) => self.partial_cmp(v4),
+        match other {
+            IpAddr::V4(v4) => self.partial_cmp(v4),
             IpAddr::V6(_) => Some(Ordering::Less),
         }
     }
@@ -1335,9 +1338,9 @@ impl PartialEq for Ipv6Addr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialEq<IpAddr> for Ipv6Addr {
     fn eq(&self, other: &IpAddr) -> bool {
-        match *other {
+        match other {
             IpAddr::V4(_) => false,
-            IpAddr::V6(ref v6) => self == v6,
+            IpAddr::V6(v6) => self == v6,
         }
     }
 }
@@ -1345,9 +1348,9 @@ impl PartialEq<IpAddr> for Ipv6Addr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialEq<Ipv6Addr> for IpAddr {
     fn eq(&self, other: &Ipv6Addr) -> bool {
-        match *self {
+        match self {
             IpAddr::V4(_) => false,
-            IpAddr::V6(ref v6) => v6 == other,
+            IpAddr::V6(v6) => v6 == other,
         }
     }
 }
@@ -1372,9 +1375,9 @@ impl PartialOrd for Ipv6Addr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialOrd<Ipv6Addr> for IpAddr {
     fn partial_cmp(&self, other: &Ipv6Addr) -> Option<Ordering> {
-        match *self {
+        match self {
             IpAddr::V4(_) => Some(Ordering::Less),
-            IpAddr::V6(ref v6) => v6.partial_cmp(other),
+            IpAddr::V6(v6) => v6.partial_cmp(other),
         }
     }
 }
@@ -1382,9 +1385,9 @@ impl PartialOrd<Ipv6Addr> for IpAddr {
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialOrd<IpAddr> for Ipv6Addr {
     fn partial_cmp(&self, other: &IpAddr) -> Option<Ordering> {
-        match *other {
+        match other {
             IpAddr::V4(_) => Some(Ordering::Greater),
-            IpAddr::V6(ref v6) => self.partial_cmp(v6),
+            IpAddr::V6(v6) => self.partial_cmp(v6),
         }
     }
 }
diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 08c3e154978..f8f0bbd5bc2 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -414,12 +414,8 @@ pub fn env() -> Env {
     unsafe {
         let _guard = ENV_LOCK.lock();
         let mut environ = *environ();
-        if environ == ptr::null() {
-            panic!("os::env() failure getting env string from OS: {}",
-                   io::Error::last_os_error());
-        }
         let mut result = Vec::new();
-        while *environ != ptr::null() {
+        while environ != ptr::null() && *environ != ptr::null() {
             if let Some(key_value) = parse(CStr::from_ptr(*environ).to_bytes()) {
                 result.push(key_value);
             }