diff --git a/src/libstd/sys/wasi/fd.rs b/src/libstd/sys/wasi/fd.rs
index 1e05e701759..29e1880b8f1 100644
--- a/src/libstd/sys/wasi/fd.rs
+++ b/src/libstd/sys/wasi/fd.rs
@@ -23,25 +23,25 @@ pub type RiFlags = u16;
 pub type RoFlags = u16;
 pub type SiFlags = u16;
 
-fn iovec(a: &mut [IoVecMut]) -> (*const libc::__wasi_iovec_t, usize) {
+fn iovec(a: &mut [IoVecMut<'_>]) -> (*const libc::__wasi_iovec_t, usize) {
     assert_eq!(
-        mem::size_of::<IoVecMut>(),
+        mem::size_of::<IoVecMut<'_>>(),
         mem::size_of::<libc::__wasi_iovec_t>()
     );
     assert_eq!(
-        mem::align_of::<IoVecMut>(),
+        mem::align_of::<IoVecMut<'_>>(),
         mem::align_of::<libc::__wasi_iovec_t>()
     );
     (a.as_ptr() as *const libc::__wasi_iovec_t, a.len())
 }
 
-fn ciovec(a: &[IoVec]) -> (*const libc::__wasi_ciovec_t, usize) {
+fn ciovec(a: &[IoVec<'_>]) -> (*const libc::__wasi_ciovec_t, usize) {
     assert_eq!(
-        mem::size_of::<IoVec>(),
+        mem::size_of::<IoVec<'_>>(),
         mem::size_of::<libc::__wasi_ciovec_t>()
     );
     assert_eq!(
-        mem::align_of::<IoVec>(),
+        mem::align_of::<IoVec<'_>>(),
         mem::align_of::<libc::__wasi_ciovec_t>()
     );
     (a.as_ptr() as *const libc::__wasi_ciovec_t, a.len())
@@ -56,28 +56,28 @@ impl WasiFd {
         cvt_wasi(unsafe { libc::__wasi_fd_datasync(self.fd) })
     }
 
-    pub fn pread(&self, bufs: &mut [IoVecMut], offset: u64) -> io::Result<usize> {
+    pub fn pread(&self, bufs: &mut [IoVecMut<'_>], offset: u64) -> io::Result<usize> {
         let mut read = 0;
         let (ptr, len) = iovec(bufs);
         cvt_wasi(unsafe { libc::__wasi_fd_pread(self.fd, ptr, len, offset, &mut read) })?;
         Ok(read)
     }
 
-    pub fn pwrite(&self, bufs: &[IoVec], offset: u64) -> io::Result<usize> {
+    pub fn pwrite(&self, bufs: &[IoVec<'_>], offset: u64) -> io::Result<usize> {
         let mut read = 0;
         let (ptr, len) = ciovec(bufs);
         cvt_wasi(unsafe { libc::__wasi_fd_pwrite(self.fd, ptr, len, offset, &mut read) })?;
         Ok(read)
     }
 
-    pub fn read(&self, bufs: &mut [IoVecMut]) -> io::Result<usize> {
+    pub fn read(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
         let mut read = 0;
         let (ptr, len) = iovec(bufs);
         cvt_wasi(unsafe { libc::__wasi_fd_read(self.fd, ptr, len, &mut read) })?;
         Ok(read)
     }
 
-    pub fn write(&self, bufs: &[IoVec]) -> io::Result<usize> {
+    pub fn write(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
         let mut read = 0;
         let (ptr, len) = ciovec(bufs);
         cvt_wasi(unsafe { libc::__wasi_fd_write(self.fd, ptr, len, &mut read) })?;
@@ -281,7 +281,7 @@ impl WasiFd {
 
     pub fn sock_recv(
         &self,
-        ri_data: &mut [IoVecMut],
+        ri_data: &mut [IoVecMut<'_>],
         ri_flags: RiFlags,
     ) -> io::Result<(usize, RoFlags)> {
         let mut ro_datalen = 0;
@@ -293,7 +293,7 @@ impl WasiFd {
         Ok((ro_datalen, ro_flags))
     }
 
-    pub fn sock_send(&self, si_data: &[IoVec], si_flags: SiFlags) -> io::Result<usize> {
+    pub fn sock_send(&self, si_data: &[IoVec<'_>], si_flags: SiFlags) -> io::Result<usize> {
         let mut so_datalen = 0;
         let (ptr, len) = ciovec(si_data);
         cvt_wasi(unsafe { libc::__wasi_sock_send(self.fd, ptr, len, si_flags, &mut so_datalen) })?;
diff --git a/src/libstd/sys/wasi/fs.rs b/src/libstd/sys/wasi/fs.rs
index 485d2c87fbd..68c8e9356a8 100644
--- a/src/libstd/sys/wasi/fs.rs
+++ b/src/libstd/sys/wasi/fs.rs
@@ -82,7 +82,7 @@ impl Eq for FilePermissions {
 }
 
 impl fmt::Debug for FilePermissions {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
@@ -125,13 +125,13 @@ impl Hash for FileType {
 }
 
 impl fmt::Debug for FileType {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
 
 impl fmt::Debug for ReadDir {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
@@ -236,7 +236,7 @@ impl DirBuilder {
 }
 
 impl fmt::Debug for File {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
diff --git a/src/libstd/sys/wasi/net.rs b/src/libstd/sys/wasi/net.rs
index af9a22f5b7a..1579aa4b572 100644
--- a/src/libstd/sys/wasi/net.rs
+++ b/src/libstd/sys/wasi/net.rs
@@ -94,7 +94,7 @@ impl TcpStream {
 }
 
 impl fmt::Debug for TcpStream {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
@@ -144,7 +144,7 @@ impl TcpListener {
 }
 
 impl fmt::Debug for TcpListener {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
@@ -282,7 +282,7 @@ impl UdpSocket {
 }
 
 impl fmt::Debug for UdpSocket {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
diff --git a/src/libstd/sys/wasi/os.rs b/src/libstd/sys/wasi/os.rs
index de18e4ba950..6d4d6aae61b 100644
--- a/src/libstd/sys/wasi/os.rs
+++ b/src/libstd/sys/wasi/os.rs
@@ -41,7 +41,7 @@ pub fn chdir(_: &path::Path) -> io::Result<()> {
 
 pub struct SplitPaths<'a>(&'a Void);
 
-pub fn split_paths(_unparsed: &OsStr) -> SplitPaths {
+pub fn split_paths(_unparsed: &OsStr) -> SplitPaths<'_> {
     panic!("unsupported")
 }
 
@@ -62,7 +62,7 @@ pub fn join_paths<I, T>(_paths: I) -> Result<OsString, JoinPathsError>
 }
 
 impl fmt::Display for JoinPathsError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         "not supported on wasm yet".fmt(f)
     }
 }
diff --git a/src/libstd/sys/wasi/path.rs b/src/libstd/sys/wasi/path.rs
index 5c062e7c97c..7a183956107 100644
--- a/src/libstd/sys/wasi/path.rs
+++ b/src/libstd/sys/wasi/path.rs
@@ -11,7 +11,7 @@ pub fn is_verbatim_sep(b: u8) -> bool {
     b == b'/'
 }
 
-pub fn parse_prefix(_: &OsStr) -> Option<Prefix> {
+pub fn parse_prefix(_: &OsStr) -> Option<Prefix<'_>> {
     None
 }
 
diff --git a/src/libstd/sys/wasi/process.rs b/src/libstd/sys/wasi/process.rs
index c49daaa1632..a02e009d953 100644
--- a/src/libstd/sys/wasi/process.rs
+++ b/src/libstd/sys/wasi/process.rs
@@ -73,7 +73,7 @@ impl From<File> for Stdio {
 }
 
 impl fmt::Debug for Command {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Ok(())
     }
 }
@@ -108,13 +108,13 @@ impl Eq for ExitStatus {
 }
 
 impl fmt::Debug for ExitStatus {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }
 
 impl fmt::Display for ExitStatus {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {}
     }
 }