Auto merge of #28090 - mystor:derive-unsafe-trait, r=Manishearth

Author: bors

src/libsyntax/ext/deriving/bounds.rs

@@ -40,6 +40,7 @@ pub fn expand_deriving_copy(cx: &mut ExtCtxt,
         path: path,
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: Vec::new(),
         associated_types: Vec::new(),
     };

src/libsyntax/ext/deriving/clone.rs

@@ -31,6 +31,7 @@ pub fn expand_deriving_clone(cx: &mut ExtCtxt,
         path: path_std!(cx, core::clone::Clone),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             MethodDef {
                 name: "clone",

src/libsyntax/ext/deriving/cmp/eq.rs

@@ -51,6 +51,7 @@ pub fn expand_deriving_eq(cx: &mut ExtCtxt,
         path: path_std!(cx, core::cmp::Eq),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             MethodDef {
                 name: "assert_receiver_is_total_eq",

src/libsyntax/ext/deriving/cmp/ord.rs

@@ -32,6 +32,7 @@ pub fn expand_deriving_ord(cx: &mut ExtCtxt,
         path: path_std!(cx, core::cmp::Ord),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             MethodDef {
                 name: "cmp",

src/libsyntax/ext/deriving/cmp/partial_eq.rs

@@ -85,6 +85,7 @@ pub fn expand_deriving_partial_eq(cx: &mut ExtCtxt,
         path: path_std!(cx, core::cmp::PartialEq),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             md!("eq", cs_eq),
             md!("ne", cs_ne)

src/libsyntax/ext/deriving/cmp/partial_ord.rs

@@ -73,6 +73,7 @@ pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt,
         path: path_std!(cx, core::cmp::PartialOrd),
         additional_bounds: vec![],
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec![
             partial_cmp_def,
             md!("lt", true, false),

src/libsyntax/ext/deriving/decodable.rs

@@ -59,6 +59,7 @@ fn expand_deriving_decodable_imp(cx: &mut ExtCtxt,
         path: Path::new_(vec!(krate, "Decodable"), None, vec!(), true),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             MethodDef {
                 name: "decode",

src/libsyntax/ext/deriving/default.rs

@@ -31,6 +31,7 @@ pub fn expand_deriving_default(cx: &mut ExtCtxt,
         path: path_std!(cx, core::default::Default),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             MethodDef {
                 name: "default",

src/libsyntax/ext/deriving/encodable.rs

@@ -135,6 +135,7 @@ fn expand_deriving_encodable_imp(cx: &mut ExtCtxt,
         path: Path::new_(vec!(krate, "Encodable"), None, vec!(), true),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
+        is_unsafe: false,
         methods: vec!(
             MethodDef {
                 name: "encode",

src/libsyntax/ext/deriving/generic/mod.rs

@@ -229,6 +229,9 @@ pub struct TraitDef<'a> {
     /// Any extra lifetimes and/or bounds, e.g. `D: serialize::Decoder`
     pub generics: LifetimeBounds<'a>,
 
+    /// Is it an `unsafe` trait?
+    pub is_unsafe: bool,
+
     pub methods: Vec<MethodDef<'a>>,
 
     pub associated_types: Vec<(ast::Ident, Ty<'a>)>,
@@ -625,11 +628,18 @@ impl<'a> TraitDef<'a> {
                                            InternedString::new("unused_qualifications"))]));
         let mut a = vec![attr, unused_qual];
         a.extend(self.attributes.iter().cloned());
+
+        let unsafety = if self.is_unsafe {
+            ast::Unsafety::Unsafe
+        } else {
+            ast::Unsafety::Normal
+        };
+
         cx.item(
             self.span,
             ident,
             a,
-            ast::ItemImpl(ast::Unsafety::Normal,
+            ast::ItemImpl(unsafety,
                           ast::ImplPolarity::Positive,
                           trait_generics,
                           opt_trait_ref,