Auto merge of #130253 - workingjubilee:rollup-npqpnaf, r=workingjubilee

Rollup of 10 pull requests

Successful merges:

 - #129103 (Don't warn empty branches unreachable for now)
 - #129696 (update stdarch)
 - #129835 (enable const-float-classify test, and test_next_up/down on 32bit x86)
 - #130077 (Fix linking error when compiling for 32-bit watchOS)
 - #130114 (Remove needless returns detected by clippy in the compiler)
 - #130168 (maint: update docs for change_time ext and doc links)
 - #130228 (notify Miri when intrinsics are changed)
 - #130239 (miri: fix overflow detection for unsigned pointer offset)
 - #130244 (Use the same span for attributes and Try expansion of ?)
 - #130248 (Limit `libc::link` usage to `nto70` target only, not NTO OS)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast/src/ast_traits.rs

@@ -153,7 +153,7 @@ impl HasTokens for StmtKind {
             StmtKind::Let(local) => local.tokens.as_ref(),
             StmtKind::Item(item) => item.tokens(),
             StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.tokens(),
-            StmtKind::Empty => return None,
+            StmtKind::Empty => None,
             StmtKind::MacCall(mac) => mac.tokens.as_ref(),
         }
     }
@@ -162,7 +162,7 @@ impl HasTokens for StmtKind {
             StmtKind::Let(local) => Some(&mut local.tokens),
             StmtKind::Item(item) => item.tokens_mut(),
             StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.tokens_mut(),
-            StmtKind::Empty => return None,
+            StmtKind::Empty => None,
             StmtKind::MacCall(mac) => Some(&mut mac.tokens),
         }
     }

compiler/rustc_ast_lowering/src/expr.rs

@@ -1837,7 +1837,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             Safety::Default,
             sym::allow,
             sym::unreachable_code,
-            self.lower_span(span),
+            try_span,
         );
         let attrs: AttrVec = thin_vec![attr];
 

compiler/rustc_attr/src/builtin.rs

@@ -1240,5 +1240,5 @@ pub fn parse_confusables(attr: &Attribute) -> Option<Vec<Symbol>> {
         candidates.push(meta_lit.symbol);
     }
 
-    return Some(candidates);
+    Some(candidates)
 }

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3669,7 +3669,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 reinits.push(location);
                 return true;
             }
-            return false;
+            false
         };
 
         while let Some(location) = stack.pop() {

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -214,7 +214,7 @@ impl<'me, 'bccx, 'tcx> NllTypeRelating<'me, 'bccx, 'tcx> {
         let delegate = FnMutDelegate {
             regions: &mut |br: ty::BoundRegion| {
                 if let Some(ex_reg_var) = reg_map.get(&br) {
-                    return *ex_reg_var;
+                    *ex_reg_var
                 } else {
                     let ex_reg_var = self.next_existential_region_var(true, br.kind.get_name());
                     debug!(?ex_reg_var);

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -290,7 +290,7 @@ pub(crate) fn check_tied_features(
             }
         }
     }
-    return None;
+    None
 }
 
 /// Used to generate cfg variables and apply features

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -438,7 +438,7 @@ fn link_rlib<'a>(
         ab.add_file(&lib)
     }
 
-    return Ok(ab);
+    Ok(ab)
 }
 
 /// Extract all symbols defined in raw-dylib libraries, collated by library name.
@@ -1319,15 +1319,15 @@ fn link_sanitizer_runtime(
     fn find_sanitizer_runtime(sess: &Session, filename: &str) -> PathBuf {
         let path = sess.target_tlib_path.dir.join(filename);
         if path.exists() {
-            return sess.target_tlib_path.dir.clone();
+            sess.target_tlib_path.dir.clone()
         } else {
             let default_sysroot =
                 filesearch::get_or_default_sysroot().expect("Failed finding sysroot");
             let default_tlib = filesearch::make_target_lib_path(
                 &default_sysroot,
                 sess.opts.target_triple.triple(),
             );
-            return default_tlib;
+            default_tlib
         }
     }
 

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -1484,7 +1484,6 @@ impl<'a> Linker for L4Bender<'a> {
     fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[String]) {
         // ToDo, not implemented, copy from GCC
         self.sess.dcx().emit_warn(errors::L4BenderExportingSymbolsUnimplemented);
-        return;
     }
 
     fn subsystem(&mut self, subsystem: &str) {

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -171,10 +171,10 @@ pub(super) fn get_metadata_xcoff<'a>(path: &Path, data: &'a [u8]) -> Result<&'a
                 "Metadata at offset {offset} with size {len} is beyond .info section"
             ));
         }
-        return Ok(&info_data[offset..(offset + len)]);
+        Ok(&info_data[offset..(offset + len)])
     } else {
-        return Err(format!("Unable to find symbol {AIX_METADATA_SYMBOL_NAME}"));
-    };
+        Err(format!("Unable to find symbol {AIX_METADATA_SYMBOL_NAME}"))
+    }
 }
 
 pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static>> {
@@ -413,7 +413,7 @@ fn macho_object_build_version_for_target(target: &Target) -> object::write::Mach
 
 /// Is Apple's CPU subtype `arm64e`s
 fn macho_is_arm64e(target: &Target) -> bool {
-    return target.llvm_target.starts_with("arm64e");
+    target.llvm_target.starts_with("arm64e")
 }
 
 pub enum MetadataPosition {

compiler/rustc_const_eval/src/interpret/call.rs

@@ -235,13 +235,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         if self.layout_compat(caller_abi.layout, callee_abi.layout)? {
             // Ensure that our checks imply actual ABI compatibility for this concrete call.
             assert!(caller_abi.eq_abi(callee_abi));
-            return Ok(true);
+            Ok(true)
         } else {
             trace!(
                 "check_argument_compat: incompatible ABIs:\ncaller: {:?}\ncallee: {:?}",
                 caller_abi, callee_abi
             );
-            return Ok(false);
+            Ok(false)
         }
     }
 

compiler/rustc_const_eval/src/interpret/operator.rs

@@ -303,8 +303,10 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let pointee_layout = self.layout_of(pointee_ty)?;
                 assert!(pointee_layout.abi.is_sized());
 
-                // We cannot overflow i64 as a type's size must be <= isize::MAX.
+                // The size always fits in `i64` as it can be at most `isize::MAX`.
                 let pointee_size = i64::try_from(pointee_layout.size.bytes()).unwrap();
+                // This uses the same type as `right`, which can be `isize` or `usize`.
+                // `pointee_size` is guaranteed to fit into both types.
                 let pointee_size = ImmTy::from_int(pointee_size, right.layout);
                 // Multiply element size and element count.
                 let (val, overflowed) = self
@@ -316,6 +318,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
 
                 let offset_bytes = val.to_target_isize(self)?;
+                if !right.layout.abi.is_signed() && offset_bytes < 0 {
+                    // We were supposed to do an unsigned offset but the result is negative -- this
+                    // can only mean that the cast wrapped around.
+                    throw_ub!(PointerArithOverflow)
+                }
                 let offset_ptr = self.ptr_offset_inbounds(ptr, offset_bytes)?;
                 Ok(ImmTy::from_scalar(Scalar::from_maybe_pointer(offset_ptr, self), left.layout))
             }

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -773,34 +773,34 @@ fn extract_symbol_from_pnr<'a>(
     match pnr {
         ParseNtResult::Ident(nt_ident, is_raw) => {
             if let IdentIsRaw::Yes = is_raw {
-                return Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR));
+                Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR))
+            } else {
+                Ok(nt_ident.name)
             }
-            return Ok(nt_ident.name);
         }
         ParseNtResult::Tt(TokenTree::Token(
             Token { kind: TokenKind::Ident(symbol, is_raw), .. },
             _,
         )) => {
             if let IdentIsRaw::Yes = is_raw {
-                return Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR));
+                Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR))
+            } else {
+                Ok(*symbol)
             }
-            return Ok(*symbol);
         }
         ParseNtResult::Tt(TokenTree::Token(
             Token {
                 kind: TokenKind::Literal(Lit { kind: LitKind::Str, symbol, suffix: None }),
                 ..
             },
             _,
-        )) => {
-            return Ok(*symbol);
-        }
+        )) => Ok(*symbol),
         ParseNtResult::Nt(nt)
             if let Nonterminal::NtLiteral(expr) = &**nt
                 && let ExprKind::Lit(Lit { kind: LitKind::Str, symbol, suffix: None }) =
                     &expr.kind =>
         {
-            return Ok(*symbol);
+            Ok(*symbol)
         }
         _ => Err(dcx
             .struct_err(

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1038,7 +1038,7 @@ fn report_trait_method_mismatch<'tcx>(
         false,
     );
 
-    return diag.emit();
+    diag.emit()
 }
 
 fn check_region_bounds_on_impl_item<'tcx>(

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -274,7 +274,7 @@ fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<()
                         return false;
                     }
 
-                    return true;
+                    true
                 })
                 .collect::<Vec<_>>();
 

compiler/rustc_hir_typeck/src/closure.rs

@@ -605,7 +605,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             Abi::Rust,
         ));
 
-        return Some(ExpectedSig { cause_span, sig });
+        Some(ExpectedSig { cause_span, sig })
     }
 
     fn sig_of_closure(

compiler/rustc_hir_typeck/src/demand.rs

@@ -1042,7 +1042,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return true;
             }
         }
-        return false;
+        false
     }
 
     fn explain_self_literal(

compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs

@@ -307,7 +307,7 @@ impl<'tcx> ArgMatrix<'tcx> {
                 permutation.into_iter().map(|x| x.unwrap()).collect();
             return Some(Issue::Permutation(final_permutation));
         }
-        return None;
+        None
     }
 
     // Obviously, detecting exact user intention is impossible, so the goal here is to
@@ -410,6 +410,6 @@ impl<'tcx> ArgMatrix<'tcx> {
         // sort errors with same type by the order they appear in the source
         // so that suggestion will be handled properly, see #112507
         errors.sort();
-        return (errors, matched_inputs);
+        (errors, matched_inputs)
     }
 }

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -2051,7 +2051,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let span = expr.span.find_oldest_ancestor_in_same_ctxt();
         err.span_suggestion_verbose(span.shrink_to_hi(), msg, sugg, Applicability::HasPlaceholders);
-        return true;
+        true
     }
 
     pub(crate) fn suggest_coercing_result_via_try_operator(

compiler/rustc_infer/src/infer/mod.rs

@@ -1481,7 +1481,7 @@ impl<'tcx> InferCtxt<'tcx> {
         // This hoists the borrow/release out of the loop body.
         let inner = self.inner.try_borrow();
 
-        return move |infer_var: TyOrConstInferVar| match (infer_var, &inner) {
+        move |infer_var: TyOrConstInferVar| match (infer_var, &inner) {
             (TyOrConstInferVar::Ty(ty_var), Ok(inner)) => {
                 use self::type_variable::TypeVariableValue;
 
@@ -1491,7 +1491,7 @@ impl<'tcx> InferCtxt<'tcx> {
                 )
             }
             _ => false,
-        };
+        }
     }
 
     /// `ty_or_const_infer_var_changed` is equivalent to one of these two:

compiler/rustc_lint/src/for_loops_over_fallibles.rs

@@ -133,7 +133,7 @@ fn extract_iterator_next_call<'tcx>(
     {
         Some(recv)
     } else {
-        return None;
+        None
     }
 }
 

compiler/rustc_middle/src/hir/map/mod.rs

@@ -71,7 +71,7 @@ impl<'hir> Iterator for ParentHirIterator<'hir> {
         debug_assert_ne!(parent_id, self.current_id);
 
         self.current_id = parent_id;
-        return Some(parent_id);
+        Some(parent_id)
     }
 }
 
@@ -103,7 +103,7 @@ impl<'hir> Iterator for ParentOwnerIterator<'hir> {
         self.current_id = HirId::make_owner(parent_id.def_id);
 
         let node = self.map.tcx.hir_owner_node(self.current_id.owner);
-        return Some((self.current_id.owner, node));
+        Some((self.current_id.owner, node))
     }
 }
 
@@ -1233,14 +1233,14 @@ pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> Mod
         body_owners,
         ..
     } = collector;
-    return ModuleItems {
+    ModuleItems {
         submodules: submodules.into_boxed_slice(),
         free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
         body_owners: body_owners.into_boxed_slice(),
-    };
+    }
 }
 
 pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
@@ -1262,14 +1262,14 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
         ..
     } = collector;
 
-    return ModuleItems {
+    ModuleItems {
         submodules: submodules.into_boxed_slice(),
         free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
         body_owners: body_owners.into_boxed_slice(),
-    };
+    }
 }
 
 struct ItemCollector<'tcx> {

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -641,7 +641,7 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
     pub fn write_uninit(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult {
         self.mark_init(range, false);
         self.provenance.clear(range, cx)?;
-        return Ok(());
+        Ok(())
     }
 
     /// Remove all provenance in the given memory range.

compiler/rustc_middle/src/mir/mod.rs

@@ -1166,10 +1166,9 @@ impl<'tcx> LocalDecl<'tcx> {
     /// Returns `true` if this is a DerefTemp
     pub fn is_deref_temp(&self) -> bool {
         match self.local_info() {
-            LocalInfo::DerefTemp => return true,
-            _ => (),
+            LocalInfo::DerefTemp => true,
+            _ => false,
         }
-        return false;
     }
 
     /// Returns `true` is the local is from a compiler desugaring, e.g.,

compiler/rustc_middle/src/ty/context.rs

@@ -2007,7 +2007,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 ));
             }
         }
-        return None;
+        None
     }
 
     /// Checks if the bound region is in Impl Item.

compiler/rustc_middle/src/ty/region.rs

@@ -431,7 +431,7 @@ impl BoundRegionKind {
 
     pub fn get_id(&self) -> Option<DefId> {
         match *self {
-            BoundRegionKind::BrNamed(id, _) => return Some(id),
+            BoundRegionKind::BrNamed(id, _) => Some(id),
             _ => None,
         }
     }