Remove identity casts

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -686,7 +686,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     fn bclose_maybe_open(&mut self, span: rustc_span::Span, empty: bool, close_box: bool) {
         let has_comment = self.maybe_print_comment(span.hi());
         if !empty || has_comment {
-            self.break_offset_if_not_bol(1, -(INDENT_UNIT as isize));
+            self.break_offset_if_not_bol(1, -INDENT_UNIT);
         }
         self.word("}");
         if close_box {

compiler/rustc_hir_pretty/src/lib.rs

@@ -242,7 +242,7 @@ pub fn enum_def_to_string(
 impl<'a> State<'a> {
     pub fn bclose_maybe_open(&mut self, span: rustc_span::Span, close_box: bool) {
         self.maybe_print_comment(span.hi());
-        self.break_offset_if_not_bol(1, -(INDENT_UNIT as isize));
+        self.break_offset_if_not_bol(1, -INDENT_UNIT);
         self.word("}");
         if close_box {
             self.end(); // close the outer-box

compiler/rustc_llvm/src/lib.rs

@@ -30,7 +30,7 @@ pub unsafe extern "C" fn LLVMRustStringWriteImpl(
     ptr: *const c_char,
     size: size_t,
 ) {
-    let slice = slice::from_raw_parts(ptr as *const u8, size as usize);
+    let slice = slice::from_raw_parts(ptr as *const u8, size);
 
     sr.bytes.borrow_mut().extend_from_slice(slice);
 }

compiler/rustc_middle/src/mir/patch.rs

@@ -133,21 +133,21 @@ impl<'tcx> MirPatch<'tcx> {
         let mut new_decl = LocalDecl::new(ty, span).internal();
         **new_decl.local_info.as_mut().assert_crate_local() = local_info;
         self.new_locals.push(new_decl);
-        Local::new(index as usize)
+        Local::new(index)
     }
 
     pub fn new_temp(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
         let index = self.next_local;
         self.next_local += 1;
         self.new_locals.push(LocalDecl::new(ty, span));
-        Local::new(index as usize)
+        Local::new(index)
     }
 
     pub fn new_internal(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
         let index = self.next_local;
         self.next_local += 1;
         self.new_locals.push(LocalDecl::new(ty, span).internal());
-        Local::new(index as usize)
+        Local::new(index)
     }
 
     pub fn new_block(&mut self, data: BasicBlockData<'tcx>) -> BasicBlock {

compiler/rustc_middle/src/mir/tcx.rs

@@ -98,7 +98,7 @@ impl<'tcx> PlaceTy<'tcx> {
                     ty::Array(inner, _) if !from_end => tcx.mk_array(*inner, (to - from) as u64),
                     ty::Array(inner, size) if from_end => {
                         let size = size.eval_target_usize(tcx, param_env);
-                        let len = size - (from as u64) - (to as u64);
+                        let len = size - from - to;
                         tcx.mk_array(*inner, len)
                     }
                     _ => bug!("cannot subslice non-array type: `{:?}`", self),

compiler/rustc_middle/src/ty/consts/int.rs

@@ -337,7 +337,7 @@ impl ScalarInt {
     /// Fails if the size of the `ScalarInt` is not equal to `Size { raw: 16 }`
     /// and returns the `ScalarInt`s size in that case.
     pub fn try_to_i128(self) -> Result<i128, Size> {
-        self.try_to_int(Size::from_bits(128)).map(|v| i128::try_from(v).unwrap())
+        self.try_to_int(Size::from_bits(128))
     }
 }
 

compiler/rustc_middle/src/ty/sty.rs

@@ -1891,7 +1891,7 @@ impl<'tcx> Ty<'tcx> {
                         // The way we evaluate the `N` in `[T; N]` here only works since we use
                         // `simd_size_and_type` post-monomorphization. It will probably start to ICE
                         // if we use it in generic code. See the `simd-array-trait` ui test.
-                        (f0_len.eval_target_usize(tcx, ParamEnv::empty()) as u64, *f0_elem_ty)
+                        (f0_len.eval_target_usize(tcx, ParamEnv::empty()), *f0_elem_ty)
                     }
                     // Otherwise, the fields of this Adt are the SIMD components (and we assume they
                     // all have the same type).

compiler/rustc_parse/src/lexer/mod.rs

@@ -558,8 +558,8 @@ impl<'a> StringReader<'a> {
         }
 
         if let Some(possible_offset) = possible_offset {
-            let lo = start + BytePos(possible_offset as u32);
-            let hi = lo + BytePos(found_terminators as u32);
+            let lo = start + BytePos(possible_offset);
+            let hi = lo + BytePos(found_terminators);
             let span = self.mk_sp(lo, hi);
             err.span_suggestion(
                 span,