Add some convenience helper methods on hir::Safety

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -6,7 +6,7 @@ use rustc_errors::{DiagMessage, SubdiagMessage, struct_span_code_err};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId};
 use rustc_hir::weak_lang_items::WEAK_LANG_ITEMS;
-use rustc_hir::{self as hir, HirId, LangItem, lang_items};
+use rustc_hir::{HirId, LangItem, lang_items};
 use rustc_middle::middle::codegen_fn_attrs::{
     CodegenFnAttrFlags, CodegenFnAttrs, PatchableFunctionEntry,
 };
@@ -251,7 +251,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             sym::target_feature => {
                 if !tcx.is_closure_like(did.to_def_id())
                     && let Some(fn_sig) = fn_sig()
-                    && fn_sig.skip_binder().safety() == hir::Safety::Safe
+                    && fn_sig.skip_binder().safety().is_safe()
                 {
                     if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc {
                         // The `#[target_feature]` attribute is allowed on

compiler/rustc_const_eval/src/const_eval/fn_queries.rs

@@ -53,9 +53,8 @@ fn is_promotable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
             Some(stab) => {
                 if cfg!(debug_assertions) && stab.promotable {
                     let sig = tcx.fn_sig(def_id);
-                    assert_eq!(
-                        sig.skip_binder().safety(),
-                        hir::Safety::Safe,
+                    assert!(
+                        sig.skip_binder().safety().is_safe(),
                         "don't mark const unsafe fns as promotable",
                         // https://github.com/rust-lang/rust/pull/53851#issuecomment-418760682
                     );

compiler/rustc_hir/src/hir.rs

@@ -3401,6 +3401,19 @@ impl Safety {
             Self::Safe => "",
         }
     }
+
+    #[inline]
+    pub fn is_unsafe(self) -> bool {
+        !self.is_safe()
+    }
+
+    #[inline]
+    pub fn is_safe(self) -> bool {
+        match self {
+            Self::Unsafe => false,
+            Self::Safe => true,
+        }
+    }
 }
 
 impl fmt::Display for Safety {
@@ -3445,7 +3458,7 @@ impl FnHeader {
     }
 
     pub fn is_unsafe(&self) -> bool {
-        matches!(&self.safety, Safety::Unsafe)
+        self.safety.is_unsafe()
     }
 }
 

compiler/rustc_hir_analysis/src/check/check.rs

@@ -6,7 +6,7 @@ use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::MultiSpan;
 use rustc_errors::codes::*;
 use rustc_hir::def::{CtorKind, DefKind};
-use rustc_hir::{Node, Safety, intravisit};
+use rustc_hir::{Node, intravisit};
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::{Obligation, ObligationCauseCode};
 use rustc_lint_defs::builtin::{
@@ -161,7 +161,7 @@ fn check_unsafe_fields(tcx: TyCtxt<'_>, item_def_id: LocalDefId) {
     };
     let typing_env = ty::TypingEnv::non_body_analysis(tcx, item_def_id);
     for field in def.all_fields() {
-        if field.safety != Safety::Unsafe {
+        if !field.safety.is_unsafe() {
             continue;
         }
         let Ok(field_ty) = tcx.try_normalize_erasing_regions(typing_env, field.ty(tcx, args))

compiler/rustc_hir_typeck/src/coercion.rs

@@ -863,7 +863,8 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             let outer_universe = self.infcx.universe();
 
             let result = if let ty::FnPtr(_, hdr_b) = b.kind()
-                && let (hir::Safety::Safe, hir::Safety::Unsafe) = (fn_ty_a.safety(), hdr_b.safety)
+                && fn_ty_a.safety().is_safe()
+                && hdr_b.safety.is_unsafe()
             {
                 let unsafe_a = self.tcx.safe_to_unsafe_fn_ty(fn_ty_a);
                 self.unify_and(unsafe_a, b, to_unsafe)
@@ -925,7 +926,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
 
                     // Safe `#[target_feature]` functions are not assignable to safe fn pointers (RFC 2396).
 
-                    if b_hdr.safety == hir::Safety::Safe
+                    if b_hdr.safety.is_safe()
                         && !self.tcx.codegen_fn_attrs(def_id).target_features.is_empty()
                     {
                         return Err(TypeError::TargetFeatureCast(def_id));

compiler/rustc_hir_typeck/src/fallback.rs

@@ -765,7 +765,7 @@ fn compute_unsafe_infer_vars<'a, 'tcx>(
                     if let Some(def_id) = typeck_results.type_dependent_def_id(ex.hir_id)
                         && let method_ty = self.fcx.tcx.type_of(def_id).instantiate_identity()
                         && let sig = method_ty.fn_sig(self.fcx.tcx)
-                        && let hir::Safety::Unsafe = sig.safety()
+                        && sig.safety().is_unsafe()
                     {
                         let mut collector = InferVarCollector {
                             value: (ex.hir_id, ex.span, UnsafeUseReason::Method),
@@ -785,7 +785,7 @@ fn compute_unsafe_infer_vars<'a, 'tcx>(
 
                     if func_ty.is_fn()
                         && let sig = func_ty.fn_sig(self.fcx.tcx)
-                        && let hir::Safety::Unsafe = sig.safety()
+                        && sig.safety().is_unsafe()
                     {
                         let mut collector = InferVarCollector {
                             value: (ex.hir_id, ex.span, UnsafeUseReason::Call),
@@ -816,7 +816,7 @@ fn compute_unsafe_infer_vars<'a, 'tcx>(
                     // `is_fn` excludes closures, but those can't be unsafe.
                     if ty.is_fn()
                         && let sig = ty.fn_sig(self.fcx.tcx)
-                        && let hir::Safety::Unsafe = sig.safety()
+                        && sig.safety().is_unsafe()
                     {
                         let mut collector = InferVarCollector {
                             value: (ex.hir_id, ex.span, UnsafeUseReason::Path),

compiler/rustc_middle/src/ty/context.rs

@@ -586,7 +586,7 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
     }
 
     fn trait_is_unsafe(self, trait_def_id: Self::DefId) -> bool {
-        self.trait_def(trait_def_id).safety == hir::Safety::Unsafe
+        self.trait_def(trait_def_id).safety.is_unsafe()
     }
 
     fn is_impl_trait_in_trait(self, def_id: DefId) -> bool {
@@ -722,7 +722,7 @@ impl<'tcx> rustc_type_ir::inherent::Safety<TyCtxt<'tcx>> for hir::Safety {
     }
 
     fn is_safe(self) -> bool {
-        matches!(self, hir::Safety::Safe)
+        self.is_safe()
     }
 
     fn prefix_str(self) -> &'static str {
@@ -2521,7 +2521,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// that is, a `fn` type that is equivalent in every way for being
     /// unsafe.
     pub fn safe_to_unsafe_fn_ty(self, sig: PolyFnSig<'tcx>) -> Ty<'tcx> {
-        assert_eq!(sig.safety(), hir::Safety::Safe);
+        assert!(sig.safety().is_safe());
         Ty::new_fn_ptr(self, sig.map_bound(|sig| ty::FnSig { safety: hir::Safety::Unsafe, ..sig }))
     }
 

compiler/rustc_middle/src/ty/mod.rs

@@ -33,9 +33,9 @@ use rustc_data_structures::intern::Interned;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::steal::Steal;
 use rustc_errors::{Diag, ErrorGuaranteed, StashKey};
+use rustc_hir::LangItem;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, DocLinkResMap, LifetimeRes, Res};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LocalDefIdMap};
-use rustc_hir::{LangItem, Safety};
 use rustc_index::IndexVec;
 use rustc_macros::{
     Decodable, Encodable, HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable,
@@ -1279,7 +1279,7 @@ impl VariantDef {
 
     /// Returns whether this variant has unsafe fields.
     pub fn has_unsafe_fields(&self) -> bool {
-        self.fields.iter().any(|x| x.safety == Safety::Unsafe)
+        self.fields.iter().any(|x| x.safety.is_unsafe())
     }
 }
 

compiler/rustc_middle/src/ty/util.rs

@@ -1291,7 +1291,7 @@ impl<'tcx> Ty<'tcx> {
     /// Checks whether this type is an ADT that has unsafe fields.
     pub fn has_unsafe_fields(self) -> bool {
         if let ty::Adt(adt_def, ..) = self.kind() {
-            adt_def.all_fields().any(|x| x.safety == hir::Safety::Unsafe)
+            adt_def.all_fields().any(|x| x.safety.is_unsafe())
         } else {
             false
         }

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -4,7 +4,7 @@ use std::ops::Bound;
 
 use rustc_errors::DiagArgValue;
 use rustc_hir::def::DefKind;
-use rustc_hir::{self as hir, BindingMode, ByRef, HirId, Mutability, Safety};
+use rustc_hir::{self as hir, BindingMode, ByRef, HirId, Mutability};
 use rustc_middle::middle::codegen_fn_attrs::TargetFeature;
 use rustc_middle::mir::BorrowKind;
 use rustc_middle::span_bug;
@@ -342,7 +342,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             PatKind::Leaf { subpatterns, .. } => {
                 if let ty::Adt(adt_def, ..) = pat.ty.kind() {
                     for pat in subpatterns {
-                        if adt_def.non_enum_variant().fields[pat.field].safety == Safety::Unsafe {
+                        if adt_def.non_enum_variant().fields[pat.field].safety.is_unsafe() {
                             self.requires_unsafe(pat.pattern.span, UseOfUnsafeField);
                         }
                     }
@@ -367,7 +367,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             PatKind::Variant { adt_def, args: _, variant_index, subpatterns } => {
                 for pat in subpatterns {
                     let field = &pat.field;
-                    if adt_def.variant(*variant_index).fields[*field].safety == Safety::Unsafe {
+                    if adt_def.variant(*variant_index).fields[*field].safety.is_unsafe() {
                         self.requires_unsafe(pat.pattern.span, UseOfUnsafeField);
                     }
                 }
@@ -479,7 +479,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                 return; // don't visit the whole expression
             }
             ExprKind::Call { fun, ty: _, args: _, from_hir_call: _, fn_span: _ } => {
-                if self.thir[fun].ty.fn_sig(self.tcx).safety() == hir::Safety::Unsafe {
+                if self.thir[fun].ty.fn_sig(self.tcx).safety().is_unsafe() {
                     let func_id = if let ty::FnDef(func_id, _) = self.thir[fun].ty.kind() {
                         Some(*func_id)
                     } else {
@@ -623,7 +623,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             ExprKind::Field { lhs, variant_index, name } => {
                 let lhs = &self.thir[lhs];
                 if let ty::Adt(adt_def, _) = lhs.ty.kind() {
-                    if adt_def.variant(variant_index).fields[name].safety == Safety::Unsafe {
+                    if adt_def.variant(variant_index).fields[name].safety.is_unsafe() {
                         self.requires_unsafe(expr.span, UseOfUnsafeField);
                     } else if adt_def.is_union() {
                         if let Some(assigned_ty) = self.assignment_info {
@@ -1112,11 +1112,7 @@ pub(crate) fn check_unsafety(tcx: TyCtxt<'_>, def: LocalDefId) {
 
     let hir_id = tcx.local_def_id_to_hir_id(def);
     let safety_context = tcx.hir().fn_sig_by_hir_id(hir_id).map_or(SafetyContext::Safe, |fn_sig| {
-        if fn_sig.header.safety == hir::Safety::Unsafe {
-            SafetyContext::UnsafeFn
-        } else {
-            SafetyContext::Safe
-        }
+        if fn_sig.header.safety.is_unsafe() { SafetyContext::UnsafeFn } else { SafetyContext::Safe }
     });
     let body_target_features = &tcx.body_codegen_attrs(def.to_def_id()).target_features;
     let mut warnings = Vec::new();

compiler/rustc_passes/src/check_attr.rs

@@ -715,7 +715,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         attrs: &[Attribute],
     ) {
         match target {
-            Target::Fn => {
+            Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent)
+            | Target::Fn => {
                 // `#[target_feature]` is not allowed in lang items.
                 if let Some((lang_item, _)) = hir::lang_items::extract(attrs)
                     // Calling functions with `#[target_feature]` is
@@ -732,7 +733,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     });
                 }
             }
-            Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => {}
             // FIXME: #[target_feature] was previously erroneously allowed on statements and some
             // crates used this, so only emit a warning.
             Target::Statement => {

compiler/rustc_symbol_mangling/src/v0.rs

@@ -439,7 +439,7 @@ impl<'tcx> Printer<'tcx> for SymbolMangler<'tcx> {
                 let sig = sig_tys.with(hdr);
                 self.push("F");
                 self.in_binder(&sig, |cx, sig| {
-                    if sig.safety == hir::Safety::Unsafe {
+                    if sig.safety.is_unsafe() {
                         cx.push("U");
                     }
                     match sig.abi {

compiler/rustc_trait_selection/src/traits/misc.rs

@@ -84,7 +84,7 @@ pub fn type_allowed_to_implement_copy<'tcx>(
         return Err(CopyImplementationError::HasDestructor);
     }
 
-    if impl_safety == hir::Safety::Safe && self_type.has_unsafe_fields() {
+    if impl_safety.is_safe() && self_type.has_unsafe_fields() {
         return Err(CopyImplementationError::HasUnsafeFields);
     }
 

src/librustdoc/html/format.rs

@@ -1626,10 +1626,7 @@ pub(crate) trait PrintWithSpace {
 
 impl PrintWithSpace for hir::Safety {
     fn print_with_space(&self) -> &str {
-        match self {
-            hir::Safety::Unsafe => "unsafe ",
-            hir::Safety::Safe => "",
-        }
+        self.prefix_str()
     }
 }
 

src/librustdoc/html/render/print_item.rs

@@ -469,7 +469,7 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
 
                 let unsafety_flag = match myitem.kind {
                     clean::FunctionItem(_) | clean::ForeignFunctionItem(..)
-                        if myitem.fn_header(tcx).unwrap().safety == hir::Safety::Unsafe =>
+                        if myitem.fn_header(tcx).unwrap().safety.is_unsafe() =>
                     {
                         "<sup title=\"unsafe function\">⚠</sup>"
                     }
@@ -1926,9 +1926,7 @@ fn item_static(
             buffer,
             "{vis}{safe}static {mutability}{name}: {typ}",
             vis = visibility_print_with_space(it, cx),
-            safe = safety
-                .map(|safe| if safe == hir::Safety::Unsafe { "unsafe " } else { "" })
-                .unwrap_or(""),
+            safe = safety.map(|safe| safe.prefix_str()).unwrap_or(""),
             mutability = s.mutability.print_with_space(),
             name = it.name.unwrap(),
             typ = s.type_.print(cx)

src/librustdoc/json/conversions.rs

@@ -639,7 +639,7 @@ impl FromClean<clean::BareFunctionDecl> for FunctionPointer {
         let clean::BareFunctionDecl { safety, generic_params, decl, abi } = bare_decl;
         FunctionPointer {
             header: FunctionHeader {
-                is_unsafe: matches!(safety, rustc_hir::Safety::Unsafe),
+                is_unsafe: safety.is_unsafe(),
                 is_const: false,
                 is_async: false,
                 abi: convert_abi(abi),
@@ -669,7 +669,7 @@ impl FromClean<clean::Trait> for Trait {
     fn from_clean(trait_: clean::Trait, renderer: &JsonRenderer<'_>) -> Self {
         let tcx = renderer.tcx;
         let is_auto = trait_.is_auto(tcx);
-        let is_unsafe = trait_.safety(tcx) == rustc_hir::Safety::Unsafe;
+        let is_unsafe = trait_.safety(tcx).is_unsafe();
         let is_dyn_compatible = trait_.is_dyn_compatible(tcx);
         let clean::Trait { items, generics, bounds, .. } = trait_;
         Trait {
@@ -711,7 +711,7 @@ impl FromClean<clean::Impl> for Impl {
             ty::ImplPolarity::Negative => true,
         };
         Impl {
-            is_unsafe: safety == rustc_hir::Safety::Unsafe,
+            is_unsafe: safety.is_unsafe(),
             generics: generics.into_json(renderer),
             provided_trait_methods: provided_trait_methods
                 .into_iter()
@@ -840,7 +840,7 @@ fn convert_static(
     Static {
         type_: (*stat.type_).into_json(renderer),
         is_mutable: stat.mutability == ast::Mutability::Mut,
-        is_unsafe: safety == rustc_hir::Safety::Unsafe,
+        is_unsafe: safety.is_unsafe(),
         expr: stat
             .expr
             .map(|e| rendered_const(tcx, tcx.hir().body(e), tcx.hir().body_owner_def_id(e)))

src/tools/clippy/clippy_lints/src/derive.rs

@@ -7,7 +7,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{FnKind, Visitor, walk_expr, walk_fn, walk_item};
 use rustc_hir::{
-    self as hir, BlockCheckMode, BodyId, Expr, ExprKind, FnDecl, Impl, Item, ItemKind, Safety, UnsafeSource,
+    self as hir, BlockCheckMode, BodyId, Expr, ExprKind, FnDecl, Impl, Item, ItemKind, UnsafeSource,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter;
@@ -421,7 +421,7 @@ impl<'tcx> Visitor<'tcx> for UnsafeVisitor<'_, 'tcx> {
         id: LocalDefId,
     ) -> Self::Result {
         if let Some(header) = kind.header()
-            && header.safety == Safety::Unsafe
+            && header.safety.is_unsafe()
         {
             ControlFlow::Break(())
         } else {

src/tools/clippy/clippy_lints/src/eta_reduction.rs

@@ -281,7 +281,7 @@ fn check_inputs(
 }
 
 fn check_sig<'tcx>(closure_sig: FnSig<'tcx>, call_sig: FnSig<'tcx>) -> bool {
-    call_sig.safety == Safety::Safe && !has_late_bound_to_non_late_bound_regions(closure_sig, call_sig)
+    call_sig.safety.is_safe() && !has_late_bound_to_non_late_bound_regions(closure_sig, call_sig)
 }
 
 /// This walks through both signatures and checks for any time a late-bound region is expected by an

src/tools/clippy/clippy_lints/src/functions/misnamed_getters.rs

@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::source::snippet;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
-use rustc_hir::{Body, ExprKind, FnDecl, ImplicitSelfKind, Safety};
+use rustc_hir::{Body, ExprKind, FnDecl, ImplicitSelfKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 use rustc_span::Span;
@@ -34,7 +34,7 @@ pub fn check_fn(cx: &LateContext<'_>, kind: FnKind<'_>, decl: &FnDecl<'_>, body:
         ImplicitSelfKind::None => return,
     };
 
-    let name = if sig.header.safety == Safety::Unsafe {
+    let name = if sig.header.safety.is_unsafe() {
         name.strip_suffix("_unchecked").unwrap_or(name)
     } else {
         name