Check gated attributes before and after macro expansion

This is important because attributes can affect expansion.

Author: Keegan McAllister

src/libsyntax/feature_gate.rs

@@ -196,6 +196,7 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType)] = &[
     ("no_mangle", Normal),
     ("no_link", Normal),
     ("derive", Normal),
+    ("deriving", Normal), // deprecation err in expansion
     ("should_fail", Normal),
     ("should_panic", Normal),
     ("ignore", Normal),
@@ -235,6 +236,9 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType)] = &[
                                    "the `#[rustc_move_fragments]` attribute \
                                     is an experimental feature")),
 
+    ("allow_internal_unstable", Gated("allow_internal_unstable",
+                                      EXPLAIN_ALLOW_INTERNAL_UNSTABLE)),
+
     // FIXME: #14408 whitelist docs since rustdoc looks at them
     ("doc", Whitelisted),
 
@@ -369,6 +373,33 @@ impl<'a> Context<'a> {
     fn has_feature(&self, feature: &str) -> bool {
         self.features.iter().any(|&n| n == feature)
     }
+
+    fn check_attribute(&self, attr: &ast::Attribute) {
+        debug!("check_attribute(attr = {:?})", attr);
+        let name = &*attr.name();
+        for &(n, ty) in KNOWN_ATTRIBUTES {
+            if n == name {
+                if let Gated(gate, desc) = ty {
+                    self.gate_feature(gate, attr.span, desc);
+                }
+                debug!("check_attribute: {:?} is known, {:?}", name, ty);
+                return;
+            }
+        }
+        if name.starts_with("rustc_") {
+            self.gate_feature("rustc_attrs", attr.span,
+                              "unless otherwise specified, attributes \
+                               with the prefix `rustc_` \
+                               are reserved for internal compiler diagnostics");
+        } else {
+            self.gate_feature("custom_attribute", attr.span,
+                       format!("The attribute `{}` is currently \
+                                unknown to the the compiler and \
+                                may have meaning \
+                                added to it in the future",
+                                name).as_slice());
+        }
+    }
 }
 
 pub fn emit_feature_err(diag: &SpanHandler, feature: &str, span: Span, explain: &str) {
@@ -436,10 +467,7 @@ impl<'a, 'v> Visitor<'v> for MacroVisitor<'a> {
     }
 
     fn visit_attribute(&mut self, attr: &'v ast::Attribute) {
-        if attr.name() == "allow_internal_unstable" {
-            self.context.gate_feature("allow_internal_unstable", attr.span,
-                                      EXPLAIN_ALLOW_INTERNAL_UNSTABLE)
-        }
+        self.context.check_attribute(attr);
     }
 }
 
@@ -456,6 +484,12 @@ impl<'a> PostExpansionVisitor<'a> {
 }
 
 impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
+    fn visit_attribute(&mut self, attr: &ast::Attribute) {
+        if !self.context.cm.span_allows_unstable(attr.span) {
+            self.context.check_attribute(attr);
+        }
+    }
+
     fn visit_name(&mut self, sp: Span, name: ast::Name) {
         if !token::get_name(name).is_ascii() {
             self.gate_feature("non_ascii_idents", sp,
@@ -556,12 +590,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
     }
 
     fn visit_foreign_item(&mut self, i: &ast::ForeignItem) {
-        if attr::contains_name(&i.attrs, "linkage") {
-            self.gate_feature("linkage", i.span,
-                              "the `linkage` attribute is experimental \
-                               and not portable across platforms")
-        }
-
         let links_to_llvm = match attr::first_attr_value_str_by_name(&i.attrs,
                                                                      "link_name") {
             Some(val) => val.starts_with("llvm."),
@@ -636,33 +664,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
         visit::walk_expr(self, e);
     }
 
-    fn visit_attribute(&mut self, attr: &ast::Attribute) {
-        debug!("visit_attribute(attr = {:?})", attr);
-        let name = &*attr.name();
-        for &(n, ty) in KNOWN_ATTRIBUTES {
-            if n == name {
-                if let Gated(gate, desc) = ty {
-                    self.gate_feature(gate, attr.span, desc);
-                }
-                debug!("visit_attribute: {:?} is known, {:?}", name, ty);
-                return;
-            }
-        }
-        if name.starts_with("rustc_") {
-            self.gate_feature("rustc_attrs", attr.span,
-                              "unless otherwise specified, attributes \
-                               with the prefix `rustc_` \
-                               are reserved for internal compiler diagnostics");
-        } else {
-            self.gate_feature("custom_attribute", attr.span,
-                       format!("The attribute `{}` is currently \
-                                unknown to the the compiler and \
-                                may have meaning \
-                                added to it in the future",
-                                name).as_slice());
-        }
-    }
-
     fn visit_pat(&mut self, pattern: &ast::Pat) {
         match pattern.node {
             ast::PatVec(_, Some(_), ref last) if !last.is_empty() => {

src/test/compile-fail/deprecated-phase.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(custom_attribute)]
+
 #[phase(blah)]
 //~^ ERROR #[phase] is deprecated
 extern crate foo;

src/test/compile-fail/feature-gate-intrinsics-and-lang-items.rs renamed to src/test/compile-fail/feature-gate-intrinsics.rs

@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#[lang="foo"]   //~ ERROR language items are subject to change
-trait Foo {}
-
 extern "rust-intrinsic" {   //~ ERROR intrinsics are subject to change
     fn bar();
 }
@@ -20,4 +17,3 @@ extern "rust-intrinsic" fn baz() {  //~ ERROR intrinsics are subject to change
 
 fn main() {
 }
-

src/test/compile-fail/feature-gate-lang-items.rs

@@ -0,0 +1,15 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[lang="foo"]   //~ ERROR language items are subject to change
+trait Foo {}
+
+fn main() {
+}

src/test/compile-fail/linkage1.rs

@@ -11,5 +11,4 @@
 extern {
     #[linkage = "extern_weak"] static foo: isize;
     //~^ ERROR: the `linkage` attribute is experimental and not portable
-    //~^^ ERROR: the `linkage` attribute is experimental and not portable
 }

src/test/compile-fail/malformed-plugin-1.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(plugin)]
 #![plugin] //~ ERROR malformed plugin attribute
 
 fn main() {}

src/test/compile-fail/malformed-plugin-2.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(plugin)]
 #![plugin="bleh"] //~ ERROR malformed plugin attribute
 
 fn main() {}

src/test/compile-fail/malformed-plugin-3.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(plugin)]
 #![plugin(foo="bleh")] //~ ERROR malformed plugin attribute
 
 fn main() {}

src/test/compile-fail/plugin-extern-crate-attr-deprecated.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(plugin)]
+
 #[plugin]  //~ ERROR #[plugin] on `extern crate` is deprecated
 //~^ HELP use a crate attribute instead, i.e. #![plugin(std)]
 extern crate std;

src/test/compile-fail/reserved-attr-on-macro.rs

@@ -0,0 +1,18 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[rustc_attribute_should_be_reserved] //~ ERROR attributes with the prefix `rustc_` are reserved
+macro_rules! foo {
+    () => (());
+}
+
+fn main() {
+    foo!();
+}