auto merge of #14952 : alexcrichton/rust/const-unsafe-pointers, r=brson

This does not yet change the compiler and libraries from `*T` to `*const T` as
it will require a snapshot to do so.

cc #7362

---

Note that the corresponding RFC, https://github.com/rust-lang/rfcs/pull/68, has not yet been accepted. It was [discussed at the last meeting](https://github.com/rust-lang/rust/wiki/Meeting-weekly-2014-06-10#rfc-pr-68-unsafe-pointers-rename-t-to-const-t) and decided to be accepted, however. I figured I'd get started on the preliminary work for the RFC that will be required regardless.

2 files changed, 17 insertions, 4 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index e3a028ed4d6..e1319304e04 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1365,7 +1365,7 @@ impl<'a> Parser<'a> {
         } else if self.token == token::BINOP(token::STAR) {
             // STAR POINTER (bare pointer?)
             self.bump();
-            TyPtr(self.parse_mt())
+            TyPtr(self.parse_ptr())
         } else if self.token == token::LBRACKET {
             // VECTOR
             self.expect(&token::LBRACKET);
@@ -1442,6 +1442,19 @@ impl<'a> Parser<'a> {
         return TyRptr(opt_lifetime, mt);
     }
 
+    pub fn parse_ptr(&mut self) -> MutTy {
+        let mutbl = if self.eat_keyword(keywords::Mut) {
+            MutMutable
+        } else if self.eat_keyword(keywords::Const) {
+            MutImmutable
+        } else {
+            // NOTE: after a stage0 snap this should turn into a span_err.
+            MutImmutable
+        };
+        let t = self.parse_ty(true);
+        MutTy { ty: t, mutbl: mutbl }
+    }
+
     pub fn is_named_argument(&mut self) -> bool {
         let offset = match self.token {
             token::BINOP(token::AND) => 1,
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index a2af417ed79..8e36339b0e5 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -512,11 +512,11 @@ declare_special_idents_and_keywords! {
         (40,                         Continue,   "continue");
         (41,                         Proc,       "proc");
         (42,                         Box,        "box");
+        (43,                         Const,      "const");
 
         'reserved:
-        (43,                         Alignof,    "alignof");
-        (44,                         Be,         "be");
-        (45,                         Const,      "const");
+        (44,                         Alignof,    "alignof");
+        (45,                         Be,         "be");
         (46,                         Offsetof,   "offsetof");
         (47,                         Priv,       "priv");
         (48,                         Pure,       "pure");