Feature gate the 128 bit types

Dangling a carrot in front of a donkey.

This commit includes manual merge conflict resolution changes from a rebase by @est31.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 625af803458..a3f2cd3a0cd 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -321,6 +321,9 @@ declare_features! (
 
     // `extern "ptx-*" fn()`
     (active, abi_ptx, "1.15.0", None),
+
+    // The `i128` type
+    (active, i128_type, "1.15.0", Some(35118)),
 );
 
 declare_features! (
@@ -1215,6 +1218,18 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 gate_feature_post!(&self, loop_break_value, e.span,
                                    "`break` with a value is experimental");
             }
+            ast::ExprKind::Lit(ref lit) => {
+                if let ast::LitKind::Int(_, ref ty) = lit.node {
+                    match *ty {
+                        ast::LitIntType::Signed(ast::IntTy::I128) |
+                        ast::LitIntType::Unsigned(ast::UintTy::U128) => {
+                            gate_feature_post!(&self, i128_type, e.span,
+                                               "128-bit integers are not stable");
+                        }
+                        _ => {}
+                    }
+                }
+            }
             _ => {}
         }
         visit::walk_expr(self, e);