rustc: Obsolete the @ syntax entirely

This removes all remnants of `@` pointers from rustc. Additionally, this removes
the `GC` structure from the prelude as it seems odd exporting an experimental
type in the prelude by default.

Closes #14193
[breaking-change]

src/libsyntax/ast.rs

@@ -21,7 +21,7 @@ use std::fmt;
 use std::fmt::Show;
 use std::option::Option;
 use std::rc::Rc;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 use serialize::{Encodable, Decodable, Encoder, Decoder};
 
 /// A pointer abstraction. FIXME(eddyb) #10676 use Rc<T> in the future.

src/libsyntax/ast_map.rs

@@ -20,7 +20,7 @@ use util::small_vector::SmallVector;
 
 use std::cell::RefCell;
 use std::fmt;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 use std::iter;
 use std::slice;
 

src/libsyntax/ast_util.rs

@@ -21,7 +21,7 @@ use visit;
 
 use std::cell::Cell;
 use std::cmp;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 use std::u32;
 
 pub fn path_name_i(idents: &[Ident]) -> String {

src/libsyntax/attr.rs

@@ -22,7 +22,7 @@ use crateid::CrateId;
 
 use std::collections::HashSet;
 use std::collections::BitvSet;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 local_data_key!(used_attrs: BitvSet)
 

src/libsyntax/ext/asm.rs

@@ -20,6 +20,8 @@ use parse;
 use parse::token::InternedString;
 use parse::token;
 
+use std::gc::GC;
+
 enum State {
     Asm,
     Outputs,

src/libsyntax/ext/base.rs

@@ -20,7 +20,7 @@ use parse::token::{InternedString, intern, str_to_ident};
 use util::small_vector::SmallVector;
 
 use std::collections::HashMap;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 // new-style macro! tt code:
 //

src/libsyntax/ext/build.rs

@@ -21,7 +21,7 @@ use parse::token::special_idents;
 use parse::token::InternedString;
 use parse::token;
 
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 // Transitional reexports so qquote can find the paths it is looking for
 mod syntax {

src/libsyntax/ext/concat_idents.rs

@@ -16,7 +16,7 @@ use owned_slice::OwnedSlice;
 use parse::token;
 use parse::token::{str_to_ident};
 
-use std::string::String;
+use std::gc::GC;
 
 pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
                          -> Box<base::MacResult> {

src/libsyntax/ext/deriving/generic/mod.rs

@@ -178,7 +178,7 @@ StaticEnum(<ast::EnumDef of C>, ~[(<ident of C0>, <span of C0>, Unnamed(~[<span
 */
 
 use std::cell::RefCell;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 use ast;
 use ast::{P, EnumDef, Expr, Ident, Generics, StructDef};

src/libsyntax/ext/expand.rs

@@ -29,7 +29,7 @@ use visit;
 use visit::Visitor;
 use util::small_vector::SmallVector;
 
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 pub fn expand_expr(e: Gc<ast::Expr>, fld: &mut MacroExpander) -> Gc<ast::Expr> {
     match e.node {
@@ -1030,6 +1030,8 @@ mod test {
     use visit;
     use visit::Visitor;
 
+    use std::gc::GC;
+
     // a visitor that extracts the paths
     // from a given thingy and puts them in a mutable
     // array (passed in to the traversal)

src/libsyntax/ext/format.rs

@@ -20,7 +20,7 @@ use rsparse = parse;
 
 use parse = fmt_macros;
 use std::collections::HashMap;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 #[deriving(PartialEq)]
 enum ArgumentType {

src/libsyntax/ext/tt/macro_parser.rs

@@ -22,6 +22,7 @@ use parse::token::{Token, EOF, Nonterminal};
 use parse::token;
 
 use std::rc::Rc;
+use std::gc::GC;
 use std::collections::HashMap;
 
 /* This is an Earley-like parser, without support for in-grammar nonterminals,

src/libsyntax/fold.rs

@@ -17,7 +17,7 @@ use owned_slice::OwnedSlice;
 use util::small_vector::SmallVector;
 
 use std::rc::Rc;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 // We may eventually want to be able to fold over type parameters, too.
 pub trait Folder {

src/libsyntax/parse/attr.rs

@@ -16,7 +16,7 @@ use parse::token;
 use parse::parser::Parser;
 use parse::token::INTERPOLATED;
 
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 // a parser that can parse attributes.
 pub trait ParserAttr {

src/libsyntax/parse/mod.rs

@@ -282,6 +282,7 @@ mod test {
     use std::io;
     use std::io::MemWriter;
     use std::str;
+    use std::gc::GC;
     use codemap::{Span, BytePos, Spanned};
     use owned_slice::OwnedSlice;
     use ast;

src/libsyntax/parse/obsolete.rs

@@ -22,7 +22,7 @@ use codemap::{Span, respan};
 use parse::parser;
 use parse::token;
 
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 /// The specific types of unsupported syntax
 #[deriving(PartialEq, Eq, Hash)]
@@ -31,6 +31,8 @@ pub enum ObsoleteSyntax {
     ObsoleteOwnedExpr,
     ObsoleteOwnedPattern,
     ObsoleteOwnedVector,
+    ObsoleteManagedType,
+    ObsoleteManagedExpr,
 }
 
 pub trait ParserObsoleteMethods {
@@ -68,6 +70,14 @@ impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
                 "`~[T]` is no longer a type",
                 "use the `Vec` type instead"
             ),
+            ObsoleteManagedType => (
+                "`@` notation for managed pointers",
+                "use `Gc<T>` in `std::gc` instead"
+            ),
+            ObsoleteManagedExpr => (
+                "`@` notation for a managed pointer allocation",
+                "use the `box(GC)` oeprator instead of `@`"
+            ),
         };
 
         self.report(sp, kind, kind_str, desc);

src/libsyntax/parse/parser.rs

@@ -79,7 +79,7 @@ use owned_slice::OwnedSlice;
 use std::collections::HashSet;
 use std::mem::replace;
 use std::rc::Rc;
-use std::gc::Gc;
+use std::gc::{Gc, GC};
 
 #[allow(non_camel_case_types)]
 #[deriving(PartialEq)]
@@ -1342,6 +1342,8 @@ impl<'a> Parser<'a> {
         } else if self.token == token::AT {
             // MANAGED POINTER
             self.bump();
+            let span = self.last_span;
+            self.obsolete(span, ObsoleteManagedType);
             TyBox(self.parse_ty(plus_allowed))
         } else if self.token == token::TILDE {
             // OWNED POINTER
@@ -2375,9 +2377,10 @@ impl<'a> Parser<'a> {
           }
           token::AT => {
             self.bump();
+            let span = self.last_span;
+            self.obsolete(span, ObsoleteManagedExpr);
             let e = self.parse_prefix_expr();
             hi = e.span.hi;
-            // HACK: pretending @[] is a (removed) @-vec
             ex = self.mk_unary(UnBox, e);
           }
           token::TILDE => {

src/libsyntax/util/parser_testing.rs

@@ -15,6 +15,8 @@ use parse::{new_parser_from_source_str};
 use parse::parser::Parser;
 use parse::token;
 
+use std::gc::Gc;
+
 // map a string to tts, using a made-up filename:
 pub fn string_to_tts(source_str: String) -> Vec<ast::TokenTree> {
     let ps = new_parse_sess();
@@ -46,21 +48,21 @@ pub fn string_to_crate (source_str : String) -> ast::Crate {
 }
 
 // parse a string, return an expr
-pub fn string_to_expr (source_str : String) -> @ast::Expr {
+pub fn string_to_expr (source_str : String) -> Gc<ast::Expr> {
     with_error_checking_parse(source_str, |p| {
         p.parse_expr()
     })
 }
 
 // parse a string, return an item
-pub fn string_to_item (source_str : String) -> Option<@ast::Item> {
+pub fn string_to_item (source_str : String) -> Option<Gc<ast::Item>> {
     with_error_checking_parse(source_str, |p| {
         p.parse_item(Vec::new())
     })
 }
 
 // parse a string, return a stmt
-pub fn string_to_stmt(source_str : String) -> @ast::Stmt {
+pub fn string_to_stmt(source_str : String) -> Gc<ast::Stmt> {
     with_error_checking_parse(source_str, |p| {
         p.parse_stmt(Vec::new())
     })
@@ -68,7 +70,7 @@ pub fn string_to_stmt(source_str : String) -> @ast::Stmt {
 
 // parse a string, return a pat. Uses "irrefutable"... which doesn't
 // (currently) affect parsing.
-pub fn string_to_pat(source_str: String) -> @ast::Pat {
+pub fn string_to_pat(source_str: String) -> Gc<ast::Pat> {
     string_to_parser(&new_parse_sess(), source_str).parse_pat()
 }