diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index 21eb772b1b3..c3324d65663 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -50,7 +50,7 @@ struct MarkSymbolVisitor<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     tables: &'a ty::TypeckTables<'tcx>,
     live_symbols: Box<FxHashSet<ast::NodeId>>,
-    struct_has_extern_repr: bool,
+    repr_has_repr_c: bool,
     in_pat: bool,
     inherited_pub_visibility: bool,
     ignore_variant_stack: Vec<DefId>,
@@ -149,8 +149,8 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
     }
 
     fn visit_node(&mut self, node: &hir_map::Node<'tcx>) {
-        let had_extern_repr = self.struct_has_extern_repr;
-        self.struct_has_extern_repr = false;
+        let had_repr_c = self.repr_has_repr_c;
+        self.repr_has_repr_c = false;
         let had_inherited_pub_visibility = self.inherited_pub_visibility;
         self.inherited_pub_visibility = false;
         match *node {
@@ -159,7 +159,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
                     hir::ItemStruct(..) | hir::ItemUnion(..) => {
                         let def_id = self.tcx.hir.local_def_id(item.id);
                         let def = self.tcx.adt_def(def_id);
-                        self.struct_has_extern_repr = def.repr.c();
+                        self.repr_has_repr_c = def.repr.c();
 
                         intravisit::walk_item(self, &item);
                     }
@@ -187,7 +187,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
             }
             _ => ()
         }
-        self.struct_has_extern_repr = had_extern_repr;
+        self.repr_has_repr_c = had_repr_c;
         self.inherited_pub_visibility = had_inherited_pub_visibility;
     }
 
@@ -223,10 +223,10 @@ impl<'a, 'tcx> Visitor<'tcx> for MarkSymbolVisitor<'a, 'tcx> {
 
     fn visit_variant_data(&mut self, def: &'tcx hir::VariantData, _: ast::Name,
                         _: &hir::Generics, _: ast::NodeId, _: syntax_pos::Span) {
-        let has_extern_repr = self.struct_has_extern_repr;
+        let has_repr_c = self.repr_has_repr_c;
         let inherited_pub_visibility = self.inherited_pub_visibility;
         let live_fields = def.fields().iter().filter(|f| {
-            has_extern_repr || inherited_pub_visibility || f.vis == hir::Public
+            has_repr_c || inherited_pub_visibility || f.vis == hir::Public
         });
         self.live_symbols.extend(live_fields.map(|f| f.id));
 
@@ -428,7 +428,7 @@ fn find_live<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         tcx,
         tables: &ty::TypeckTables::empty(None),
         live_symbols: box FxHashSet(),
-        struct_has_extern_repr: false,
+        repr_has_repr_c: false,
         in_pat: false,
         inherited_pub_visibility: false,
         ignore_variant_stack: vec![],
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index e5f6ac88530..8f87f5b1e1a 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -1538,7 +1538,7 @@ impl ReprOptions {
         for attr in tcx.get_attrs(did).iter() {
             for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
                 flags.insert(match r {
-                    attr::ReprExtern => ReprFlags::IS_C,
+                    attr::ReprC => ReprFlags::IS_C,
                     attr::ReprPacked => ReprFlags::IS_PACKED,
                     attr::ReprSimd => ReprFlags::IS_SIMD,
                     attr::ReprInt(i) => {
diff --git a/src/librustc_lint/bad_style.rs b/src/librustc_lint/bad_style.rs
index ac0bf9f4a99..ad3760eed80 100644
--- a/src/librustc_lint/bad_style.rs
+++ b/src/librustc_lint/bad_style.rs
@@ -120,17 +120,15 @@ impl LintPass for NonCamelCaseTypes {
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonCamelCaseTypes {
     fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
-        let extern_repr_count = it.attrs
+        let has_repr_c = it.attrs
             .iter()
-            .filter(|attr| {
+            .any(|attr| {
                 attr::find_repr_attrs(cx.tcx.sess.diagnostic(), attr)
                     .iter()
-                    .any(|r| r == &attr::ReprExtern)
-            })
-            .count();
-        let has_extern_repr = extern_repr_count > 0;
+                    .any(|r| r == &attr::ReprC)
+            });
 
-        if has_extern_repr {
+        if has_repr_c {
             return;
         }
 
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index 0b868b514fe..4291f811f3f 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -1008,8 +1008,7 @@ pub fn find_repr_attrs(diagnostic: &Handler, attr: &Attribute) -> Vec<ReprAttr>
                 if let Some(mi) = item.word() {
                     let word = &*mi.name().as_str();
                     let hint = match word {
-                        // Can't use "extern" because it's not a lexical identifier.
-                        "C" => Some(ReprExtern),
+                        "C" => Some(ReprC),
                         "packed" => Some(ReprPacked),
                         "simd" => Some(ReprSimd),
                         _ => match int_type_of_word(word) {
@@ -1080,7 +1079,7 @@ fn int_type_of_word(s: &str) -> Option<IntType> {
 #[derive(PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)]
 pub enum ReprAttr {
     ReprInt(IntType),
-    ReprExtern,
+    ReprC,
     ReprPacked,
     ReprSimd,
     ReprAlign(u32),
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 48872cb1313..08a7f85d14b 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -831,7 +831,7 @@ fn find_repr_type_name(diagnostic: &Handler, type_attrs: &[ast::Attribute]) -> &
         for r in &attr::find_repr_attrs(diagnostic, a) {
             repr_type_name = match *r {
                 attr::ReprPacked | attr::ReprSimd | attr::ReprAlign(_) => continue,
-                attr::ReprExtern => "i32",
+                attr::ReprC => "i32",
 
                 attr::ReprInt(attr::SignedInt(ast::IntTy::Isize)) => "isize",
                 attr::ReprInt(attr::SignedInt(ast::IntTy::I8)) => "i8",