review changes

src/librustc_lint/builtin.rs

@@ -43,8 +43,9 @@ use lint::{LintPass, LateLintPass, EarlyLintPass, EarlyContext};
 
 use std::collections::HashSet;
 
-use syntax::{ast, feature_gate};
+use syntax::ast;
 use syntax::attr;
+use syntax::feature_gate::{AttributeGate, AttributeType, Stability, deprecated_attributes};
 use syntax_pos::Span;
 
 use rustc::hir::{self, PatKind};
@@ -749,7 +750,19 @@ declare_lint! {
 
 /// Checks for use of attributes which have been deprecated.
 #[derive(Clone)]
-pub struct DeprecatedAttr;
+pub struct DeprecatedAttr {
+    // This is not free to compute, so we want to keep it around, rather than
+    // compute it for every attribute.
+    depr_attrs: Vec<&'static (&'static str, AttributeType, AttributeGate)>,
+}
+
+impl DeprecatedAttr {
+    pub fn new() -> DeprecatedAttr {
+        DeprecatedAttr {
+            depr_attrs: deprecated_attributes(),
+        }
+    }
+}
 
 impl LintPass for DeprecatedAttr {
     fn get_lints(&self) -> LintArray {
@@ -760,14 +773,16 @@ impl LintPass for DeprecatedAttr {
 impl EarlyLintPass for DeprecatedAttr {
     fn check_attribute(&mut self, cx: &EarlyContext, attr: &ast::Attribute) {
         let name = &*attr.name();
-        for &(n, _, ref g) in feature_gate::KNOWN_ATTRIBUTES {
+        for &&(n, _, ref g) in &self.depr_attrs {
             if n == name {
-                if let &feature_gate::AttributeGate::Gated(feature_gate::Stability::Deprecated,
+                if let &AttributeGate::Gated(Stability::Deprecated(link),
                                              ref name,
-                                                           ..) = g {
+                                             ref reason,
+                                             _) = g {
                     cx.span_lint(DEPRECATED,
                                  attr.span,
-                                 &format!("use of deprecated attribute: {}", name));
+                                 &format!("use of deprecated attribute `{}`: {}. See {}",
+                                          name, reason, link));
                 }
                 return;
             }

src/librustc_lint/lib.rs

@@ -37,6 +37,7 @@
 #![feature(rustc_private)]
 #![feature(slice_patterns)]
 #![feature(staged_api)]
+#![feature(dotdot_in_tuple_patterns)]
 
 #[macro_use]
 extern crate syntax;
@@ -95,6 +96,14 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
             )
     }
 
+    macro_rules! add_early_builtin_with_new {
+        ($sess:ident, $($name:ident),*,) => (
+            {$(
+                store.register_early_pass($sess, false, box $name::new());
+                )*}
+            )
+    }
+
     macro_rules! add_lint_group {
         ($sess:ident, $name:expr, $($lint:ident),*) => (
             store.register_group($sess, false, $name, vec![$(LintId::of($lint)),*]);
@@ -103,6 +112,9 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
 
     add_early_builtin!(sess,
                        UnusedParens,
+                       );
+
+    add_early_builtin_with_new!(sess,
                                 DeprecatedAttr,
                                 );
 

src/libsyntax/feature_gate.rs

@@ -377,17 +377,28 @@ pub enum AttributeGate {
     Ungated,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq)]
+impl AttributeGate {
+    fn is_deprecated(&self) -> bool {
+        match *self {
+            Gated(Stability::Deprecated(_), ..) => true,
+            _ => false,
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub enum Stability {
     Unstable,
-    Deprecated,
+    // Argument is tracking issue link.
+    Deprecated(&'static str),
 }
 
 // fn() is not Debug
 impl ::std::fmt::Debug for AttributeGate {
     fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
         match *self {
-            Gated(_, ref name, ref expl, _) => write!(fmt, "Gated({}, {})", name, expl),
+            Gated(ref stab, ref name, ref expl, _) =>
+                write!(fmt, "Gated({:?}, {}, {})", stab, name, expl),
             Ungated => write!(fmt, "Ungated")
         }
     }
@@ -402,6 +413,10 @@ macro_rules! cfg_fn {
     }}
 }
 
+pub fn deprecated_attributes() -> Vec<&'static (&'static str, AttributeType, AttributeGate)> {
+    KNOWN_ATTRIBUTES.iter().filter(|a| a.2.is_deprecated()).collect()
+}
+
 // Attributes that have a special meaning to rustc or rustdoc
 pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGate)] = &[
     // Normal attributes
@@ -643,10 +658,10 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGat
     ("link_section", Whitelisted, Ungated),
     ("no_builtins", Whitelisted, Ungated),
     ("no_mangle", Whitelisted, Ungated),
-    ("no_debug", Whitelisted, Gated(Stability::Deprecated,
+    ("no_debug", Whitelisted, Gated(
+        Stability::Deprecated("https://github.com/rust-lang/rust/issues/29721"),
         "no_debug",
-                                    "the `#[no_debug]` attribute \
+        "the `#[no_debug]` attribute is an experimental feature",
-                                     is an experimental feature",
         cfg_fn!(no_debug))),
     ("omit_gdb_pretty_printer_section", Whitelisted, Gated(Stability::Unstable,
                                                        "omit_gdb_pretty_printer_section",

src/libsyntax/lib.rs

@@ -34,6 +34,7 @@
 #![cfg_attr(stage0, feature(question_mark))]
 #![feature(rustc_diagnostic_macros)]
 #![feature(specialization)]
+#![feature(dotdot_in_tuple_patterns)]
 
 extern crate serialize;
 extern crate term;

src/test/compile-fail/feature-gate-no-debug-2.rs

@@ -11,5 +11,5 @@
 #![deny(deprecated)]
 #![feature(no_debug)]
 
-#[no_debug] //~ ERROR use of deprecated attribute: no_debug
+#[no_debug] //~ ERROR use of deprecated attribute `no_debug`
 fn main() {}