review changes

Author: Nick Cameron

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, Stability, with_deprecated_attributes};
 use syntax_pos::Span;
 
 use rustc::hir::{self, PatKind};
@@ -760,18 +761,23 @@ 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 {
-            if n == name {
-                if let &feature_gate::AttributeGate::Gated(feature_gate::Stability::Deprecated,
-                                                           ref name,
-                                                           ..) = g {
-                    cx.span_lint(DEPRECATED,
-                                 attr.span,
-                                 &format!("use of deprecated attribute: {}", name));
+        with_deprecated_attributes(|depr_attrs| {
+            for &&(n, _, ref g) in depr_attrs {
+                if n == name {
+                    if let &AttributeGate::Gated(Stability::Deprecated(link),
+                                                 ref name,
+                                                 ref reason,
+                                                 _) = g {
+                        cx.span_lint(DEPRECATED,
+                                     attr.span,
+                                     &format!("use of deprecated attribute `{}`: {}. See {}",
+                                              name, reason, link));
+                    }
+                    // Returns from the closure, skipping the rest of the loop.
+                    return;
                 }
-                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;

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 +413,21 @@ macro_rules! cfg_fn {
     }}
 }
 
+pub fn with_deprecated_attributes<F, T>(f: F) -> T
+    where F: FnOnce(&[&'static (&'static str, AttributeType, AttributeGate)]) -> T
+{
+    static mut DEPR_ATTRS: Option<Vec<&'static (&'static str, AttributeType, AttributeGate)>>
+        = None;
+
+    unsafe {
+        if DEPR_ATTRS.is_none() {
+            DEPR_ATTRS = Some(KNOWN_ATTRIBUTES.iter().filter(|a| a.2.is_deprecated()).collect());
+        }
+
+        f(DEPR_ATTRS.as_ref().unwrap())
+    }
+}
+
 // Attributes that have a special meaning to rustc or rustdoc
 pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGate)] = &[
     // Normal attributes
@@ -643,11 +669,11 @@ 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",
-                                    "the `#[no_debug]` attribute \
-                                     is an experimental feature",
-                                    cfg_fn!(no_debug))),
+    ("no_debug", Whitelisted, Gated(
+        Stability::Deprecated("https://github.com/rust-lang/rust/issues/29721"),
+        "no_debug",
+        "the `#[no_debug]` attribute is an experimental feature",
+        cfg_fn!(no_debug))),
     ("omit_gdb_pretty_printer_section", Whitelisted, Gated(Stability::Unstable,
                                                        "omit_gdb_pretty_printer_section",
                                                        "the `#[omit_gdb_pretty_printer_section]` \

src/libsyntax/lib.rs

@@ -34,6 +34,8 @@
 #![cfg_attr(stage0, feature(question_mark))]
 #![feature(rustc_diagnostic_macros)]
 #![feature(specialization)]
+#![feature(dotdot_in_tuple_patterns)]
+#![feature(drop_types_in_const)]
 
 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() {}