From 887feeeaf7d40c25caa9532f2d9121cb79fca899 Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <edy.burt@gmail.com>
Date: Wed, 12 Jun 2019 11:42:58 +0300
Subject: rustc: replace `GenericArgs::with_generic_args` hack with a plain
 getter.

---
 src/libsyntax/lib.rs |  2 ++
 src/libsyntax/ptr.rs | 11 +++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

(limited to 'src/libsyntax')

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 55db8da3276..337b8424736 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -12,6 +12,8 @@
 #![deny(unused_lifetimes)]
 
 #![feature(bind_by_move_pattern_guards)]
+#![feature(const_fn)]
+#![feature(const_transmute)]
 #![feature(crate_visibility_modifier)]
 #![feature(label_break_value)]
 #![feature(nll)]
diff --git a/src/libsyntax/ptr.rs b/src/libsyntax/ptr.rs
index d577243fb3d..f0cfa5a84a8 100644
--- a/src/libsyntax/ptr.rs
+++ b/src/libsyntax/ptr.rs
@@ -133,8 +133,15 @@ impl<T: Encodable> Encodable for P<T> {
 }
 
 impl<T> P<[T]> {
-    pub fn new() -> P<[T]> {
-        P { ptr: Default::default() }
+    pub const fn new() -> P<[T]> {
+        // HACK(eddyb) bypass the lack of a `const fn` to create an empty `Box<[T]>`
+        // (as trait methods, `default` in this case, can't be `const fn` yet).
+        P {
+            ptr: unsafe {
+                use std::ptr::NonNull;
+                std::mem::transmute(NonNull::<[T; 0]>::dangling() as NonNull<[T]>)
+            },
+        }
     }
 
     #[inline(never)]
-- 
cgit 1.4.1-3-g733a5