From 51ed1ecefd016bd90b09fea399b9a989d756609d Mon Sep 17 00:00:00 2001
From: Richo Healey <richo@psych0tik.net>
Date: Mon, 2 Feb 2015 19:33:50 -0800
Subject: [PATCH] lint: Deny #[no_mangle] const items

This renames the PrivateNoMangleFns lint to allow both to happen in a
single pass, since they do roughly the same work.
---
 src/librustc/lint/builtin.rs                  | 21 +++++++++++++++----
 src/librustc/lint/context.rs                  |  2 +-
 .../compile-fail/lint-unexported-no-mangle.rs |  9 +++++++-
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 904c9c3adb5..fdc2bed781a 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -2065,12 +2065,19 @@ fn get_lints(&self) -> LintArray {
     "functions marked #[no_mangle] should be exported"
 }
 
-#[derive(Copy)]
-pub struct PrivateNoMangleFns;
+declare_lint! {
+    NO_MANGLE_CONST_ITEMS,
+    Deny,
+    "const items will not have their symbols exported"
+}
 
-impl LintPass for PrivateNoMangleFns {
+#[derive(Copy)]
+pub struct InvalidNoMangleItems;
+
+impl LintPass for InvalidNoMangleItems {
     fn get_lints(&self) -> LintArray {
-        lint_array!(PRIVATE_NO_MANGLE_FNS)
+        lint_array!(PRIVATE_NO_MANGLE_FNS,
+                    NO_MANGLE_CONST_ITEMS)
     }
 
     fn check_item(&mut self, cx: &Context, it: &ast::Item) {
@@ -2083,6 +2090,12 @@ fn check_item(&mut self, cx: &Context, it: &ast::Item) {
                     cx.span_lint(PRIVATE_NO_MANGLE_FNS, it.span, msg.as_slice());
                 }
             },
+            ast::ItemConst(..) => {
+                if attr::contains_name(it.attrs.as_slice(), "no_mangle") {
+                    let msg = "const items should never be #[no_mangle]";
+                    cx.span_lint(NO_MANGLE_CONST_ITEMS, it.span, msg);
+                }
+            }
             _ => {},
         }
     }
diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index c649ff2635b..730a125fe97 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -213,7 +213,7 @@ macro_rules! add_lint_group {
                      UnstableFeatures,
                      Stability,
                      UnconditionalRecursion,
-                     PrivateNoMangleFns,
+                     InvalidNoMangleItems,
         );
 
         add_builtin_with_new!(sess,
diff --git a/src/test/compile-fail/lint-unexported-no-mangle.rs b/src/test/compile-fail/lint-unexported-no-mangle.rs
index 3227a78c2ef..fed1157b1cf 100644
--- a/src/test/compile-fail/lint-unexported-no-mangle.rs
+++ b/src/test/compile-fail/lint-unexported-no-mangle.rs
@@ -8,13 +8,20 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags:-F private_no_mangle_fns
+// compile-flags:-F private_no_mangle_fns -F no_mangle_const_items
 
 // FIXME(#19495) no_mangle'ing main ICE's.
 #[no_mangle]
 fn foo() { //~ ERROR function foo is marked #[no_mangle], but not exported
 }
 
+#[allow(dead_code)]
+#[no_mangle]
+const FOO: u64 = 1; //~ ERROR const items should never be #[no_mangle]
+
+#[no_mangle]
+pub const PUB_FOO: u64 = 1; //~ ERROR const items should never be #[no_mangle]
+
 #[no_mangle]
 pub fn bar()  {
 }