allow shorthand syntax for deprecation reason

src/libsyntax/attr/builtin.rs

@@ -592,18 +592,24 @@ fn find_deprecation_generic<'a, I>(sess: &ParseSess,
     let diagnostic = &sess.span_diagnostic;
 
     'outer: for attr in attrs_iter {
-        if attr.path != "deprecated" {
-            continue
+        if !attr.check_name("deprecated") {
+            continue;
         }
 
-        mark_used(attr);
-
         if depr.is_some() {
             span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes");
             break
         }
 
-        depr = if let Some(metas) = attr.meta_item_list() {
+        let meta = attr.meta().unwrap();
+        depr = match &meta.node {
+            MetaItemKind::Word => Some(Deprecation { since: None, note: None }),
+            MetaItemKind::NameValue(..) => {
+                meta.value_str().map(|note| {
+                    Deprecation { since: None, note: Some(note) }
+                })
+            }
+            MetaItemKind::List(list) => {
                 let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
                     if item.is_some() {
                         handle_errors(sess, meta.span, AttrError::MultipleItem(meta.name()));
@@ -633,7 +639,7 @@ fn find_deprecation_generic<'a, I>(sess: &ParseSess,
 
                 let mut since = None;
                 let mut note = None;
-            for meta in metas {
+                for meta in list {
                     match &meta.node {
                         NestedMetaItemKind::MetaItem(mi) => {
                             match &*mi.name().as_str() {
@@ -663,10 +669,9 @@ fn find_deprecation_generic<'a, I>(sess: &ParseSess,
                     }
                 }
 
-            Some(Deprecation {since: since, note: note})
-        } else {
-            Some(Deprecation{since: None, note: None})
+                Some(Deprecation { since, note })
             }
+        };
     }
 
     depr

src/libsyntax/attr/mod.rs

@@ -161,6 +161,10 @@ fn name_from_path(path: &Path) -> Name {
 }
 
 impl Attribute {
+    /// Returns `true` if the attribute's path matches the argument. If it matches, then the
+    /// attribute is marked as used.
+    ///
+    /// To check the attribute name without marking it used, use the `path` field directly.
     pub fn check_name(&self, name: &str) -> bool {
         let matches = self.path == name;
         if matches {

src/libsyntax/feature_gate.rs

@@ -1176,9 +1176,15 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeTemplate, Attribu
     ("stable", Whitelisted, template!(List: r#"feature = "name", since = "version""#), Ungated),
     ("unstable", Whitelisted, template!(List: r#"feature = "name", reason = "...", issue = "N""#),
                                         Ungated),
-    ("deprecated", Normal, template!(Word, List: r#"/*opt*/ since = "version",
-                                                    /*opt*/ note = "reason"#,
-                                                    NameValueStr: "reason"), Ungated),
+    ("deprecated",
+        Normal,
+        template!(
+            Word,
+            List: r#"/*opt*/ since = "version", /*opt*/ note = "reason"#,
+            NameValueStr: "reason"
+        ),
+        Ungated
+    ),
 
     ("rustc_paren_sugar", Normal, template!(Word), Gated(Stability::Unstable,
                                         "unboxed_closures",

src/test/rustdoc/deprecated.rs

@@ -26,3 +26,8 @@ pub struct V;
 //      'Deprecated$'
 #[deprecated]
 pub struct W;
+
+// @matches deprecated/struct.X.html '//*[@class="stab deprecated"]' \
+//      'Deprecated: shorthand reason$'
+#[deprecated = "shorthand reason"]
+pub struct X;

src/test/ui/deprecation/deprecation-sanity.rs

@@ -15,6 +15,12 @@ mod bogus_attribute_types_1 {
 
     #[deprecated(since(b), note = "a")] //~ ERROR incorrect meta item
     fn f6() { }
+
+    #[deprecated(note = b"test")] //~ ERROR literal in `deprecated` value must be a string
+    fn f7() { }
+
+    #[deprecated("test")] //~ ERROR item in `deprecated` must be a key/value pair
+    fn f8() { }
 }
 
 #[deprecated(since = "a", note = "b")]

src/test/ui/deprecation/deprecation-sanity.stderr

@@ -28,19 +28,31 @@ error[E0551]: incorrect meta item
 LL |     #[deprecated(since(b), note = "a")] //~ ERROR incorrect meta item
    |                  ^^^^^^^^
 
+error[E0565]: literal in `deprecated` value must be a string
+  --> $DIR/deprecation-sanity.rs:19:25
+   |
+LL |     #[deprecated(note = b"test")] //~ ERROR literal in `deprecated` value must be a string
+   |                         ^^^^^^^ help: consider removing the prefix: `"test"`
+
+error[E0565]: item in `deprecated` must be a key/value pair
+  --> $DIR/deprecation-sanity.rs:22:18
+   |
+LL |     #[deprecated("test")] //~ ERROR item in `deprecated` must be a key/value pair
+   |                  ^^^^^^
+
 error[E0550]: multiple deprecated attributes
-  --> $DIR/deprecation-sanity.rs:22:1
+  --> $DIR/deprecation-sanity.rs:28:1
    |
 LL | fn multiple1() { } //~ ERROR multiple deprecated attributes
    | ^^^^^^^^^^^^^^^^^^
 
 error[E0538]: multiple 'since' items
-  --> $DIR/deprecation-sanity.rs:24:27
+  --> $DIR/deprecation-sanity.rs:30:27
    |
 LL | #[deprecated(since = "a", since = "b", note = "c")] //~ ERROR multiple 'since' items
    |                           ^^^^^^^^^^^
 
-error: aborting due to 7 previous errors
+error: aborting due to 9 previous errors
 
-Some errors occurred: E0538, E0541, E0550, E0551.
+Some errors occurred: E0538, E0541, E0550, E0551, E0565.
 For more information about an error, try `rustc --explain E0538`.

src/test/ui/deprecation/invalid-literal.rs

@@ -0,0 +1,4 @@
+#[deprecated = b"test"] //~ ERROR attribute must be of the form
+fn foo() {}
+
+fn main() {}

src/test/ui/deprecation/invalid-literal.stderr

@@ -0,0 +1,8 @@
+error: attribute must be of the form `#[deprecated]` or `#[deprecated(/*opt*/ since = "version", /*opt*/ note = "reason)]` or `#[deprecated = "reason"]`
+  --> $DIR/invalid-literal.rs:1:1
+   |
+LL | #[deprecated = b"test"] //~ ERROR attribute must be of the form
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+