Resolve clippy::extra_unused_lifetimes

    error: this lifetime isn't used in the function definition
      --> src/helpers.rs:46:20
       |
    46 | fn try_resolve_did<'mir, 'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option<DefId> {
       |                    ^^^^
       |
       = note: `-D clippy::extra-unused-lifetimes` implied by `-D clippy::all`
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes

    error: this lifetime isn't used in the function definition
      --> src/shims/posix/fs.rs:49:12
       |
    49 |     fn dup<'tcx>(&mut self) -> io::Result<Box<dyn FileDescriptor>>;
       |            ^^^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes

    error: this lifetime isn't used in the function definition
      --> src/shims/os_str.rs:81:41
       |
    81 |         pub fn u16vec_to_osstring<'tcx, 'a>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
       |                                         ^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes

    error: this lifetime isn't used in the function definition
      --> src/thread.rs:72:26
       |
    72 |     pub fn to_u32_scalar<'tcx>(&self) -> Scalar<Tag> {
       |                          ^^^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes

Author: dtolnay

src/helpers.rs

@@ -43,7 +43,7 @@ const UNIX_IO_ERROR_TABLE: &[(std::io::ErrorKind, &str)] = {
 };
 
 /// Gets an instance for a path.
-fn try_resolve_did<'mir, 'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option<DefId> {
+fn try_resolve_did<'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option<DefId> {
     tcx.crates(()).iter().find(|&&krate| tcx.crate_name(krate).as_str() == path[0]).and_then(
         |krate| {
             let krate = DefId { krate: *krate, index: CRATE_DEF_INDEX };

src/lib.rs

@@ -14,7 +14,6 @@
     clippy::collapsible_if,
     clippy::comparison_chain,
     clippy::enum_variant_names,
-    clippy::extra_unused_lifetimes,
     clippy::field_reassign_with_default,
     clippy::from_over_into,
     clippy::if_same_then_else,

src/shims/os_str.rs

@@ -78,7 +78,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             Ok(OsString::from_wide(&u16_vec[..]))
         }
         #[cfg(not(windows))]
-        pub fn u16vec_to_osstring<'tcx, 'a>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
+        pub fn u16vec_to_osstring<'tcx>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
             let s = String::from_utf16(&u16_vec[..])
                 .map_err(|_| err_unsup_format!("{:?} is not a valid utf-16 string", u16_vec))?;
             Ok(s.into())

src/shims/posix/fs.rs

@@ -46,7 +46,7 @@ trait FileDescriptor: std::fmt::Debug {
         _communicate_allowed: bool,
     ) -> InterpResult<'tcx, io::Result<i32>>;
 
-    fn dup<'tcx>(&mut self) -> io::Result<Box<dyn FileDescriptor>>;
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>>;
 }
 
 impl FileDescriptor for FileHandle {
@@ -107,7 +107,7 @@ impl FileDescriptor for FileHandle {
         }
     }
 
-    fn dup<'tcx>(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
         let duplicated = self.file.try_clone()?;
         Ok(Box::new(FileHandle { file: duplicated, writable: self.writable }))
     }
@@ -153,7 +153,7 @@ impl FileDescriptor for io::Stdin {
         throw_unsup_format!("stdin cannot be closed");
     }
 
-    fn dup<'tcx>(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
         Ok(Box::new(io::stdin()))
     }
 }
@@ -203,7 +203,7 @@ impl FileDescriptor for io::Stdout {
         throw_unsup_format!("stdout cannot be closed");
     }
 
-    fn dup<'tcx>(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
         Ok(Box::new(io::stdout()))
     }
 }
@@ -246,7 +246,7 @@ impl FileDescriptor for io::Stderr {
         throw_unsup_format!("stderr cannot be closed");
     }
 
-    fn dup<'tcx>(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
         Ok(Box::new(io::stderr()))
     }
 }

src/thread.rs

@@ -69,7 +69,7 @@ impl From<u32> for ThreadId {
 }
 
 impl ThreadId {
-    pub fn to_u32_scalar<'tcx>(&self) -> Scalar<Tag> {
+    pub fn to_u32_scalar(&self) -> Scalar<Tag> {
         Scalar::from_u32(u32::try_from(self.0).unwrap())
     }
 }