librustc: Disallow "unsafe" for external functions

2 files changed, 16 insertions, 3 deletions

diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 3472b9f1d67..ec956f61863 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -63,6 +63,7 @@ pub enum ObsoleteSyntax {
     ObsoleteMultipleLocalDecl,
     ObsoleteMutWithMultipleBindings,
     ObsoleteExternVisibility,
+    ObsoleteUnsafeExternFn,
 }
 
 impl to_bytes::IterBytes for ObsoleteSyntax {
@@ -246,7 +247,12 @@ impl ParserObsoleteMethods for Parser {
                 "`pub extern` or `priv extern`",
                 "place the `pub` or `priv` on the individual external items \
                  instead"
-            )
+            ),
+            ObsoleteUnsafeExternFn => (
+                "unsafe external function",
+                "external functions are always unsafe; remove the `unsafe` \
+                 keyword"
+            ),
         };
 
         self.report(sp, kind, kind_str, desc);
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 1d61c5be83d..386f027d6e1 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -84,7 +84,8 @@ use parse::obsolete::{ObsoletePurity, ObsoleteStaticMethod};
 use parse::obsolete::{ObsoleteConstItem, ObsoleteFixedLengthVectorType};
 use parse::obsolete::{ObsoleteNamedExternModule, ObsoleteMultipleLocalDecl};
 use parse::obsolete::{ObsoleteMutWithMultipleBindings};
-use parse::obsolete::{ObsoleteExternVisibility, ParserObsoleteMethods};
+use parse::obsolete::{ObsoleteExternVisibility, ObsoleteUnsafeExternFn};
+use parse::obsolete::{ParserObsoleteMethods};
 use parse::token::{can_begin_expr, get_ident_interner, ident_to_str, is_ident};
 use parse::token::{is_ident_or_path};
 use parse::token::{is_plain_ident, INTERPOLATED, keywords, special_idents};
@@ -4066,14 +4067,20 @@ impl Parser {
     fn parse_item_foreign_fn(&self,  attrs: ~[Attribute]) -> @foreign_item {
         let lo = self.span.lo;
         let vis = self.parse_visibility();
+
+        // Parse obsolete purity.
         let purity = self.parse_fn_purity();
+        if purity != impure_fn {
+            self.obsolete(*self.last_span, ObsoleteUnsafeExternFn);
+        }
+
         let (ident, generics) = self.parse_fn_header();
         let decl = self.parse_fn_decl();
         let hi = self.span.hi;
         self.expect(&token::SEMI);
         @ast::foreign_item { ident: ident,
                              attrs: attrs,
-                             node: foreign_item_fn(decl, purity, generics),
+                             node: foreign_item_fn(decl, generics),
                              id: self.get_id(),
                              span: mk_sp(lo, hi),
                              vis: vis }