---

yaml
---
r: 209195
b: refs/heads/master
c: 57c75b6
h: refs/heads/master
i:
  209193: 6d4dcdf
  209191: 1de2532
v: v3

Author: nikomatsakis

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 710270d9c0b9b9e65e606e1c6109329c93499837
+refs/heads/master: 57c75b6b10c329ed1c9c1957e98a990dd04608f2
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: ba0e1cd8147d452c356aacb29fb87568ca26f111
 refs/heads/try: 7b4ef47b7805a402d756fb8157101f64880a522f

trunk/src/librustc/middle/check_const.rs

@@ -205,7 +205,16 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
                             ret_ty: Ty<'tcx>)
                             -> bool {
         if let Some(fn_like) = const_eval::lookup_const_fn_by_id(self.tcx, def_id) {
-            if self.mode != Mode::Var && !self.tcx.sess.features.borrow().const_fn {
+            if
+                // we are in a static/const initializer
+                self.mode != Mode::Var &&
+
+                // feature-gate is not enabled
+                !self.tcx.sess.features.borrow().const_fn &&
+
+                // this doesn't come from a macro that has #[allow_internal_unstable]
+                !self.tcx.sess.codemap().span_allows_unstable(expr.span)
+            {
                 self.tcx.sess.span_err(
                     expr.span,
                     &format!("const fns are an unstable feature"));