Add new fn safety enum for functions

Author: spastorino

compiler/rustc_ast/src/ast.rs

@@ -2099,7 +2099,7 @@ impl Ty {
 
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct BareFnTy {
-    pub unsafety: Unsafe,
+    pub safety: FnSafety,
     pub ext: Extern,
     pub generic_params: ThinVec<GenericParam>,
     pub decl: P<FnDecl>,
@@ -2485,6 +2485,13 @@ pub enum Unsafe {
     No,
 }
 
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
+#[derive(HashStable_Generic)]
+pub enum FnSafety {
+    Unsafe(Span),
+    Default,
+}
+
 /// Describes what kind of coroutine markers, if any, a function has.
 ///
 /// Coroutine markers are things that cause the function to generate a coroutine, such as `async`,
@@ -3001,8 +3008,8 @@ impl Extern {
 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
 pub struct FnHeader {
-    /// The `unsafe` keyword, if any
-    pub unsafety: Unsafe,
+    /// The safety keyword, if any
+    pub safety: FnSafety,
     /// Whether this is `async`, `gen`, or nothing.
     pub coroutine_kind: Option<CoroutineKind>,
     /// The `const` keyword, if any
@@ -3014,8 +3021,8 @@ pub struct FnHeader {
 impl FnHeader {
     /// Does this function header have any qualifiers or is it empty?
     pub fn has_qualifiers(&self) -> bool {
-        let Self { unsafety, coroutine_kind, constness, ext } = self;
-        matches!(unsafety, Unsafe::Yes(_))
+        let Self { safety, coroutine_kind, constness, ext } = self;
+        matches!(safety, FnSafety::Unsafe(_))
             || coroutine_kind.is_some()
             || matches!(constness, Const::Yes(_))
             || !matches!(ext, Extern::None)
@@ -3025,7 +3032,7 @@ impl FnHeader {
 impl Default for FnHeader {
     fn default() -> FnHeader {
         FnHeader {
-            unsafety: Unsafe::No,
+            safety: FnSafety::Default,
             coroutine_kind: None,
             constness: Const::No,
             ext: Extern::None,

compiler/rustc_ast/src/mut_visit.rs

@@ -499,8 +499,8 @@ pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
             vis.visit_mt(mt);
         }
         TyKind::BareFn(bft) => {
-            let BareFnTy { unsafety, ext: _, generic_params, decl, decl_span } = bft.deref_mut();
-            visit_unsafety(unsafety, vis);
+            let BareFnTy { safety, ext: _, generic_params, decl, decl_span } = bft.deref_mut();
+            visit_fn_safety(safety, vis);
             generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
             vis.visit_fn_decl(decl);
             vis.visit_span(decl_span);
@@ -864,6 +864,13 @@ fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
     }
 }
 
+fn visit_fn_safety<T: MutVisitor>(safety: &mut FnSafety, vis: &mut T) {
+    match safety {
+        FnSafety::Unsafe(span) => vis.visit_span(span),
+        FnSafety::Default => {}
+    }
+}
+
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
 fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
     match polarity {
@@ -1226,10 +1233,10 @@ fn visit_const_item<T: MutVisitor>(
 }
 
 fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
-    let FnHeader { unsafety, coroutine_kind, constness, ext: _ } = header;
+    let FnHeader { safety, coroutine_kind, constness, ext: _ } = header;
     visit_constness(constness, vis);
     coroutine_kind.as_mut().map(|coroutine_kind| vis.visit_coroutine_kind(coroutine_kind));
-    visit_unsafety(unsafety, vis);
+    visit_fn_safety(safety, vis);
 }
 
 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {