Implement `fmt::Debug` for all structures in libstd.

Part of https://github.com/rust-lang/rust/issues/31869.

Also turn on the `missing_debug_implementations` lint at the crate
level.

2 files changed, 9 insertions, 0 deletions

diff --git a/src/libstd/net/mod.rs b/src/libstd/net/mod.rs
index 56286fbe253..cadf87f32b1 100644
--- a/src/libstd/net/mod.rs
+++ b/src/libstd/net/mod.rs
@@ -12,6 +12,7 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
+use fmt;
 use io::{self, Error, ErrorKind};
 use sys_common::net as net_imp;
 
@@ -105,6 +106,13 @@ impl Iterator for LookupHost {
     fn next(&mut self) -> Option<SocketAddr> { self.0.next() }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for LookupHost {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("LookupHost { .. }")
+    }
+}
+
 /// Resolve the host specified by `host` as a number of `SocketAddr` instances.
 ///
 /// This method may perform a DNS query to resolve `host` and may also inspect
diff --git a/src/libstd/net/tcp.rs b/src/libstd/net/tcp.rs
index be9636a0a19..63817c9f10f 100644
--- a/src/libstd/net/tcp.rs
+++ b/src/libstd/net/tcp.rs
@@ -76,6 +76,7 @@ pub struct TcpListener(net_imp::TcpListener);
 /// [`incoming`]: struct.TcpListener.html#method.incoming
 /// [`TcpListener`]: struct.TcpListener.html
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Incoming<'a> { listener: &'a TcpListener }
 
 impl TcpStream {