Use field init shorthand where possible

Field init shorthand allows writing initializers like `tcx: tcx` as
`tcx`. The compiler already uses it extensively. Fix the last few places
where it isn't yet used.

compiler/rustc_const_eval/src/interpret/projection.rs

@@ -325,7 +325,7 @@ fn project_subslice<P: Projectable<'tcx, M::Provenance>>(
         let actual_to = if from_end {
             if from.checked_add(to).is_none_or(|to| to > len) {
                 // This can only be reached in ConstProp and non-rustc-MIR.
-                throw_ub!(BoundsCheckFailed { len: len, index: from.saturating_add(to) });
+                throw_ub!(BoundsCheckFailed { len, index: from.saturating_add(to) });
             }
             len.checked_sub(to).unwrap()
         } else {

compiler/rustc_lint/src/impl_trait_overcaptures.rs

@@ -177,7 +177,7 @@ fn check_fn(tcx: TyCtxt<'_>, parent_def_id: LocalDefId) {
         // Lazily compute these two, since they're likely a bit expensive.
         variances: LazyCell::new(|| {
             let mut functional_variances = FunctionalVariances {
-                tcx: tcx,
+                tcx,
                 variances: FxHashMap::default(),
                 ambient_variance: ty::Covariant,
                 generics: tcx.generics_of(parent_def_id),

compiler/rustc_parse/src/parser/pat.rs

@@ -1648,7 +1648,7 @@ fn report_misplaced_at_in_struct_pat(&self, prev_field: Ident) -> Diag<'a> {
                 ident: prev_field,
             })
         } else {
-            self.dcx().create_err(AtInStructPattern { span: span })
+            self.dcx().create_err(AtInStructPattern { span })
         }
     }
 

compiler/rustc_type_ir/src/elaborate.rs

@@ -72,7 +72,7 @@ fn child_with_derived_cause(
         _parent_trait_pred: crate::Binder<I, crate::TraitPredicate<I>>,
         _index: usize,
     ) -> Self {
-        ClauseWithSupertraitSpan { pred: clause.as_predicate(), supertrait_span: supertrait_span }
+        ClauseWithSupertraitSpan { pred: clause.as_predicate(), supertrait_span }
     }
 }
 

library/alloc/src/rc.rs

@@ -795,7 +795,7 @@ pub fn new_cyclic_in<F>(data_fn: F, alloc: A) -> Rc<T, A>
         let uninit_ptr: NonNull<_> = (unsafe { &mut *uninit_raw_ptr }).into();
         let init_ptr: NonNull<RcInner<T>> = uninit_ptr.cast();
 
-        let weak = Weak { ptr: init_ptr, alloc: alloc };
+        let weak = Weak { ptr: init_ptr, alloc };
 
         // It's important we don't give up ownership of the weak pointer, or
         // else the memory might be freed by the time `data_fn` returns. If

library/alloc/src/sync.rs

@@ -784,7 +784,7 @@ pub fn new_cyclic_in<F>(data_fn: F, alloc: A) -> Arc<T, A>
         let uninit_ptr: NonNull<_> = (unsafe { &mut *uninit_raw_ptr }).into();
         let init_ptr: NonNull<ArcInner<T>> = uninit_ptr.cast();
 
-        let weak = Weak { ptr: init_ptr, alloc: alloc };
+        let weak = Weak { ptr: init_ptr, alloc };
 
         // It's important we don't give up ownership of the weak pointer, or
         // else the memory might be freed by the time `data_fn` returns. If

library/core/src/task/wake.rs

@@ -322,7 +322,7 @@ pub const fn from_waker(waker: &'a Waker) -> Self {
         // SAFETY: LocalWaker is just Waker without thread safety
         let local_waker = unsafe { transmute(waker) };
         Self {
-            waker: waker,
+            waker,
             local_waker,
             ext: ExtData::None(()),
             _marker: PhantomData,

library/std/src/sys/pal/hermit/fs.rs

@@ -135,7 +135,7 @@ pub fn file_type(&self) -> FileType {
             S_IFREG => DT_REG,
             _ => DT_UNKNOWN,
         };
-        FileType { mode: mode }
+        FileType { mode }
     }
 }
 

library/std/src/sys/pal/hermit/thread.rs

@@ -43,7 +43,7 @@ pub unsafe fn new_with_coreid(
             }
             Err(io::const_error!(io::ErrorKind::Uncategorized, "Unable to create thread!"))
         } else {
-            Ok(Thread { tid: tid })
+            Ok(Thread { tid })
         };
 
         extern "C" fn thread_start(main: usize) {

library/std/src/sys/pal/hermit/time.rs

@@ -22,7 +22,7 @@ const fn zero() -> Timespec {
     const fn new(tv_sec: i64, tv_nsec: i32) -> Timespec {
         assert!(tv_nsec >= 0 && tv_nsec < NSEC_PER_SEC);
         // SAFETY: The assert above checks tv_nsec is within the valid range
-        Timespec { t: timespec { tv_sec: tv_sec, tv_nsec: tv_nsec } }
+        Timespec { t: timespec { tv_sec, tv_nsec } }
     }
 
     fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {

library/std/src/sys/pal/sgx/fd.rs

@@ -12,7 +12,7 @@ pub struct FileDesc {
 
 impl FileDesc {
     pub fn new(fd: Fd) -> FileDesc {
-        FileDesc { fd: fd }
+        FileDesc { fd }
     }
 
     pub fn raw(&self) -> Fd {

rustfmt.toml

@@ -4,6 +4,7 @@ use_small_heuristics = "Max"
 merge_derives = false
 group_imports = "StdExternalCrate"
 imports_granularity = "Module"
+use_field_init_shorthand = true
 
 # Files to ignore. Each entry uses gitignore syntax, but `!` prefixes aren't allowed.
 ignore = [

src/tools/compiletest/src/read2.rs

@@ -286,7 +286,7 @@ pub fn read2(
     impl<'a> Pipe<'a> {
         unsafe fn new<P: IntoRawHandle>(p: P, dst: &'a mut Vec<u8>) -> Pipe<'a> {
             Pipe {
-                dst: dst,
+                dst,
                 pipe: NamedPipe::from_raw_handle(p.into_raw_handle()),
                 overlapped: Overlapped::zero(),
                 done: false,

tests/codegen-units/item-collection/generic-impl.rs

@@ -14,7 +14,7 @@ fn id<T>(x: T) -> T {
 
 impl<T> Struct<T> {
     fn new(x: T) -> Struct<T> {
-        Struct { x: x, f: id }
+        Struct { x, f: id }
     }
 
     fn get<T2>(self, x: T2) -> (T, T2) {

tests/codegen/issues/issue-15953.rs

@@ -9,7 +9,7 @@ struct Foo {
 #[no_mangle]
 // CHECK: memcpy
 fn interior(x: Vec<i32>) -> Vec<i32> {
-    let Foo { x } = Foo { x: x };
+    let Foo { x } = Foo { x };
     x
 }
 

tests/run-make/extern-fn-struct-passing-abi/test.rs

@@ -126,7 +126,7 @@ fn byval_rect_with_many_huge64(
 
 fn main() {
     let s = Rect { a: 553, b: 554, c: 555, d: 556 };
-    let t = BiggerRect { s: s, a: 27834, b: 7657 };
+    let t = BiggerRect { s, a: 27834, b: 7657 };
     let u = FloatRect { a: 3489, b: 3490, c: 8. };
     let v = Huge { a: 5647, b: 5648, c: 5649, d: 5650, e: 5651 };
     let w = Huge64 { a: 1234, b: 1335, c: 1436, d: 1537, e: 1638 };

tests/run-make/symbols-include-type-name/lib.rs

@@ -4,7 +4,7 @@ pub struct Def {
 
 impl Def {
     pub fn new(id: i32) -> Def {
-        Def { id: id }
+        Def { id }
     }
 }