Resolve clippy::needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/data_race.rs:565:34
        |
    565 |         this.validate_atomic_rmw(&place, atomic)?;
        |                                  ^^^^^^ help: change this to: `place`
        |
        = note: `-D clippy::needless-borrow` implied by `-D clippy::all`
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
        --> src/data_race.rs:1413:27
         |
    1413 |         clocks.clock.join(&lock);
         |                           ^^^^^ help: change this to: `lock`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/helpers.rs:326:51
        |
    326 |                         .size_and_align_of_mplace(&place)?
        |                                                   ^^^^^^ help: change this to: `place`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/helpers.rs:365:17
        |
    365 |                 &self.ecx
        |                 ^^^^^^^^^ help: change this to: `self.ecx`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/helpers.rs:634:47
        |
    634 |         let seconds_place = this.mplace_field(&tp, 0)?;
        |                                               ^^^ help: change this to: `tp`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/helpers.rs:637:51
        |
    637 |         let nanoseconds_place = this.mplace_field(&tp, 1)?;
        |                                                   ^^^ help: change this to: `tp`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/machine.rs:547:73
        |
    547 |         let link_name = match ecx.tcx.sess.first_attr_value_str_by_name(&attrs, sym::link_name) {
        |                                                                         ^^^^^^ help: change this to: `attrs`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/machine.rs:576:56
        |
    576 |             Some(data_race::AllocExtra::new_allocation(&data_race, alloc.size(), kind))
        |                                                        ^^^^^^^^^^ help: change this to: `data_race`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/foreign_items.rs:241:43
        |
    241 |             .first_attr_value_str_by_name(&attrs, sym::link_name)
        |                                           ^^^^^^ help: change this to: `attrs`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/intrinsics.rs:778:61
        |
    778 |                         .read_immediate(&this.operand_index(&index, i)?.into())?
        |                                                             ^^^^^^ help: change this to: `index`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
        --> src/shims/intrinsics.rs:1195:44
         |
    1195 |                 this.write_immediate(*old, &dest)?; // old value is returned
         |                                            ^^^^^ help: change this to: `dest`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
        --> src/shims/intrinsics.rs:1200:44
         |
    1200 |                 this.write_immediate(*old, &dest)?; // old value is returned
         |                                            ^^^^^ help: change this to: `dest`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
      --> src/shims/posix/fs.rs:54:12
       |
    54 |         Ok(&self)
       |            ^^^^^ help: change this to: `self`
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/posix/fs.rs:654:49
        |
    654 |                 let io_result = maybe_sync_file(&file, *writable, File::sync_all);
        |                                                 ^^^^^ help: change this to: `file`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/posix/fs.rs:746:52
        |
    746 |                 file_descriptor.write(communicate, &bytes)?.map(|c| i64::try_from(c).unwrap());
        |                                                    ^^^^^^ help: change this to: `bytes`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
        --> src/shims/posix/fs.rs:1494:45
         |
    1494 |             let io_result = maybe_sync_file(&file, *writable, File::sync_all);
         |                                             ^^^^^ help: change this to: `file`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
        --> src/shims/posix/fs.rs:1516:45
         |
    1516 |             let io_result = maybe_sync_file(&file, *writable, File::sync_data);
         |                                             ^^^^^ help: change this to: `file`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
        --> src/shims/posix/fs.rs:1561:45
         |
    1561 |             let io_result = maybe_sync_file(&file, *writable, File::sync_data);
         |                                             ^^^^^ help: change this to: `file`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/env.rs:232:65
        |
    232 |             let var_ptr = alloc_env_var_as_c_str(&name, &value, &mut this)?;
        |                                                                 ^^^^^^^^^ help: change this to: `this`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/env.rs:277:68
        |
    277 |             let var_ptr = alloc_env_var_as_wide_str(&name, &value, &mut this)?;
        |                                                                    ^^^^^^^^^ help: change this to: `this`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/env.rs:328:37
        |
    328 |         let buf = this.read_pointer(&buf_op)?;
        |                                     ^^^^^^^ help: change this to: `buf_op`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

    error: this expression creates a reference which is immediately dereferenced by the compiler
       --> src/shims/env.rs:329:37
        |
    329 |         let size = this.read_scalar(&size_op)?.to_machine_usize(&*this.tcx)?;
        |                                     ^^^^^^^^ help: change this to: `size_op`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

Author: dtolnay

src/data_race.rs

@@ -562,7 +562,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> {
 
         this.allow_data_races_mut(|this| this.write_immediate(**new_val, &(*place).into()))?;
 
-        this.validate_atomic_rmw(&place, atomic)?;
+        this.validate_atomic_rmw(place, atomic)?;
 
         // Return the old value.
         Ok(old)
@@ -1410,7 +1410,7 @@ impl GlobalState {
     /// incremented.
     pub fn validate_lock_acquire(&self, lock: &VClock, thread: ThreadId) {
         let (_, mut clocks) = self.load_thread_state_mut(thread);
-        clocks.clock.join(&lock);
+        clocks.clock.join(lock);
     }
 
     /// Release a lock handle, express that this happens-before

src/helpers.rs

@@ -323,7 +323,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     trace!("unsafe_cell_action on {:?}", place.ptr);
                     // We need a size to go on.
                     let unsafe_cell_size = this
-                        .size_and_align_of_mplace(&place)?
+                        .size_and_align_of_mplace(place)?
                         .map(|(size, _)| size)
                         // for extern types, just cover what we can
                         .unwrap_or_else(|| place.layout.size);
@@ -362,7 +362,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
             #[inline(always)]
             fn ecx(&self) -> &MiriEvalContext<'mir, 'tcx> {
-                &self.ecx
+                self.ecx
             }
 
             // Hook to detect `UnsafeCell`.
@@ -631,10 +631,10 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     /// `EINVAL` in this case.
     fn read_timespec(&mut self, tp: &MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx, Option<Duration>> {
         let this = self.eval_context_mut();
-        let seconds_place = this.mplace_field(&tp, 0)?;
+        let seconds_place = this.mplace_field(tp, 0)?;
         let seconds_scalar = this.read_scalar(&seconds_place.into())?;
         let seconds = seconds_scalar.to_machine_isize(this)?;
-        let nanoseconds_place = this.mplace_field(&tp, 1)?;
+        let nanoseconds_place = this.mplace_field(tp, 1)?;
         let nanoseconds_scalar = this.read_scalar(&nanoseconds_place.into())?;
         let nanoseconds = nanoseconds_scalar.to_machine_isize(this)?;
 

src/lib.rs

@@ -18,7 +18,6 @@
     clippy::from_over_into,
     clippy::if_same_then_else,
     clippy::manual_map,
-    clippy::needless_borrow,
     clippy::needless_lifetimes,
     clippy::needless_question_mark,
     clippy::needless_return,

src/machine.rs

@@ -544,7 +544,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         def_id: DefId,
     ) -> InterpResult<'tcx, Pointer<Tag>> {
         let attrs = ecx.tcx.get_attrs(def_id);
-        let link_name = match ecx.tcx.sess.first_attr_value_str_by_name(&attrs, sym::link_name) {
+        let link_name = match ecx.tcx.sess.first_attr_value_str_by_name(attrs, sym::link_name) {
             Some(name) => name,
             None => ecx.tcx.item_name(def_id),
         };
@@ -573,7 +573,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
             None
         };
         let race_alloc = if let Some(data_race) = &ecx.machine.data_race {
-            Some(data_race::AllocExtra::new_allocation(&data_race, alloc.size(), kind))
+            Some(data_race::AllocExtra::new_allocation(data_race, alloc.size(), kind))
         } else {
             None
         };

src/shims/env.rs

@@ -210,7 +210,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         name_op: &OpTy<'tcx, Tag>,
         value_op: &OpTy<'tcx, Tag>,
     ) -> InterpResult<'tcx, i32> {
-        let mut this = self.eval_context_mut();
+        let this = self.eval_context_mut();
         let target_os = &this.tcx.sess.target.os;
         assert!(
             target_os == "linux" || target_os == "macos",
@@ -229,7 +229,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
         }
         if let Some((name, value)) = new {
-            let var_ptr = alloc_env_var_as_c_str(&name, &value, &mut this)?;
+            let var_ptr = alloc_env_var_as_c_str(&name, &value, this)?;
             if let Some(var) = this.machine.env_vars.map.insert(name, var_ptr) {
                 this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
             }
@@ -249,7 +249,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         name_op: &OpTy<'tcx, Tag>,  // LPCWSTR
         value_op: &OpTy<'tcx, Tag>, // LPCWSTR
     ) -> InterpResult<'tcx, i32> {
-        let mut this = self.eval_context_mut();
+        let this = self.eval_context_mut();
         this.assert_target_os("windows", "SetEnvironmentVariableW");
 
         let name_ptr = this.read_pointer(name_op)?;
@@ -274,7 +274,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             Ok(1) // return non-zero on success
         } else {
             let value = this.read_os_str_from_wide_str(value_ptr)?;
-            let var_ptr = alloc_env_var_as_wide_str(&name, &value, &mut this)?;
+            let var_ptr = alloc_env_var_as_wide_str(&name, &value, this)?;
             if let Some(var) = this.machine.env_vars.map.insert(name, var_ptr) {
                 this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
             }
@@ -325,8 +325,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             "`getcwd` is only available for the UNIX target family"
         );
 
-        let buf = this.read_pointer(&buf_op)?;
-        let size = this.read_scalar(&size_op)?.to_machine_usize(&*this.tcx)?;
+        let buf = this.read_pointer(buf_op)?;
+        let size = this.read_scalar(size_op)?.to_machine_usize(&*this.tcx)?;
 
         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
             this.reject_in_isolation("`getcwd`", reject_with)?;

src/shims/foreign_items.rs

@@ -238,7 +238,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let link_name = this
             .tcx
             .sess
-            .first_attr_value_str_by_name(&attrs, sym::link_name)
+            .first_attr_value_str_by_name(attrs, sym::link_name)
             .unwrap_or_else(|| this.tcx.item_name(def_id));
         let tcx = this.tcx.tcx;
 

src/shims/intrinsics.rs

@@ -775,7 +775,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
                 for i in 0..dest_len {
                     let src_index: u64 = this
-                        .read_immediate(&this.operand_index(&index, i)?.into())?
+                        .read_immediate(&this.operand_index(index, i)?.into())?
                         .to_scalar()?
                         .to_u32()?
                         .into();
@@ -1192,12 +1192,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         match atomic_op {
             AtomicOp::Min => {
                 let old = this.atomic_min_max_scalar(&place, rhs, true, atomic)?;
-                this.write_immediate(*old, &dest)?; // old value is returned
+                this.write_immediate(*old, dest)?; // old value is returned
                 Ok(())
             }
             AtomicOp::Max => {
                 let old = this.atomic_min_max_scalar(&place, rhs, false, atomic)?;
-                this.write_immediate(*old, &dest)?; // old value is returned
+                this.write_immediate(*old, dest)?; // old value is returned
                 Ok(())
             }
             AtomicOp::MirOp(op, neg) => {

src/shims/posix/fs.rs

@@ -51,7 +51,7 @@ trait FileDescriptor: std::fmt::Debug {
 
 impl FileDescriptor for FileHandle {
     fn as_file_handle<'tcx>(&self) -> InterpResult<'tcx, &FileHandle> {
-        Ok(&self)
+        Ok(self)
     }
 
     fn read<'tcx>(
@@ -651,7 +651,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
                 // FIXME: Support fullfsync for all FDs
                 let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
-                let io_result = maybe_sync_file(&file, *writable, File::sync_all);
+                let io_result = maybe_sync_file(file, *writable, File::sync_all);
                 this.try_unwrap_io_result(io_result)
             } else {
                 this.handle_not_found()
@@ -743,7 +743,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
             let bytes = this.read_bytes_ptr(buf, Size::from_bytes(count))?;
             let result =
-                file_descriptor.write(communicate, &bytes)?.map(|c| i64::try_from(c).unwrap());
+                file_descriptor.write(communicate, bytes)?.map(|c| i64::try_from(c).unwrap());
             this.try_unwrap_io_result(result)
         } else {
             this.handle_not_found()
@@ -1491,7 +1491,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
             // FIXME: Support fsync for all FDs
             let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
-            let io_result = maybe_sync_file(&file, *writable, File::sync_all);
+            let io_result = maybe_sync_file(file, *writable, File::sync_all);
             this.try_unwrap_io_result(io_result)
         } else {
             this.handle_not_found()
@@ -1513,7 +1513,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
             // FIXME: Support fdatasync for all FDs
             let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
-            let io_result = maybe_sync_file(&file, *writable, File::sync_data);
+            let io_result = maybe_sync_file(file, *writable, File::sync_data);
             this.try_unwrap_io_result(io_result)
         } else {
             this.handle_not_found()
@@ -1558,7 +1558,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
             // FIXME: Support sync_data_range for all FDs
             let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
-            let io_result = maybe_sync_file(&file, *writable, File::sync_data);
+            let io_result = maybe_sync_file(file, *writable, File::sync_data);
             this.try_unwrap_io_result(io_result)
         } else {
             this.handle_not_found()