Auto merge of #23156 - GuillaumeGomez:remove-proc, r=alexcrichton

This is the implementation of the [RFC 584](https://github.com/rust-lang/rfcs/pull/584).

src/libsyntax/parse/obsolete.rs

@@ -24,8 +24,6 @@ use ptr::P;
 pub enum ObsoleteSyntax {
     Sized,
     ForSized,
-    ProcType,
-    ProcExpr,
     ClosureType,
     ClosureKind,
     EmptyIndex,
@@ -57,16 +55,6 @@ impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
                  by default",
                 true,
             ),
-            ObsoleteSyntax::ProcType => (
-                "the `proc` type",
-                "use unboxed closures instead",
-                true,
-            ),
-            ObsoleteSyntax::ProcExpr => (
-                "`proc` expression",
-                "use a `move ||` expression instead",
-                true,
-            ),
             ObsoleteSyntax::ClosureType => (
                 "`|usize| -> bool` closure type",
                 "use unboxed closures instead, no type annotation needed",

src/libsyntax/parse/parser.rs

@@ -1051,9 +1051,7 @@ impl<'a> Parser<'a> {
         let lifetime_defs = self.parse_late_bound_lifetime_defs();
 
         // examine next token to decide to do
-        if self.eat_keyword_noexpect(keywords::Proc) {
-            self.parse_proc_type(lifetime_defs)
-        } else if self.token_is_bare_fn_keyword() || self.token_is_closure_keyword() {
+        if self.token_is_bare_fn_keyword() || self.token_is_closure_keyword() {
             self.parse_ty_bare_fn_or_ty_closure(lifetime_defs)
         } else if self.check(&token::ModSep) ||
                   self.token.is_ident() ||
@@ -1121,35 +1119,6 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// Parses a procedure type (`proc`). The initial `proc` keyword must
-    /// already have been parsed.
-    pub fn parse_proc_type(&mut self, lifetime_defs: Vec<ast::LifetimeDef>) -> Ty_ {
-        /*
-
-        proc <'lt> (S) [:Bounds] -> T
-        ^~~^ ^~~~^  ^  ^~~~~~~~^    ^
-         |     |    |      |        |
-         |     |    |      |      Return type
-         |     |    |    Bounds
-         |     |  Argument types
-         |   Legacy lifetimes
-        the `proc` keyword (already consumed)
-
-        */
-
-        let proc_span = self.last_span;
-
-        // To be helpful, parse the proc as ever
-        let _ = self.parse_legacy_lifetime_defs(lifetime_defs);
-        let _ = self.parse_fn_args(false, false);
-        let _ = self.parse_colon_then_ty_param_bounds(BoundParsingMode::Bare);
-        let _ = self.parse_ret_ty();
-
-        self.obsolete(proc_span, ObsoleteSyntax::ProcType);
-
-        TyInfer
-    }
-
     /// Parses an obsolete closure kind (`&:`, `&mut:`, or `:`).
     pub fn parse_obsolete_closure_kind(&mut self) {
          let lo = self.span.lo;
@@ -1522,8 +1491,6 @@ impl<'a> Parser<'a> {
             let e = self.parse_expr();
             self.expect(&token::CloseDelim(token::Paren));
             TyTypeof(e)
-        } else if self.eat_keyword_noexpect(keywords::Proc) {
-            self.parse_proc_type(Vec::new())
         } else if self.eat_lt() {
             // QUALIFIED PATH `<TYPE as TRAIT_REF>::item`
             let self_type = self.parse_ty_sum();
@@ -2285,12 +2252,6 @@ impl<'a> Parser<'a> {
                 if self.eat_keyword(keywords::Move) {
                     return self.parse_lambda_expr(CaptureByValue);
                 }
-                if self.eat_keyword_noexpect(keywords::Proc) {
-                    let span = self.last_span;
-                    let _ = self.parse_proc_decl();
-                    let _ = self.parse_expr();
-                    return self.obsolete_expr(span, ObsoleteSyntax::ProcExpr);
-                }
                 if self.eat_keyword(keywords::If) {
                     return self.parse_if_expr();
                 }
@@ -4645,23 +4606,6 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parses the `(arg, arg) -> return_type` header on a procedure.
-    fn parse_proc_decl(&mut self) -> P<FnDecl> {
-        let inputs =
-            self.parse_unspanned_seq(&token::OpenDelim(token::Paren),
-                                     &token::CloseDelim(token::Paren),
-                                     seq_sep_trailing_allowed(token::Comma),
-                                     |p| p.parse_fn_block_arg());
-
-        let output = self.parse_ret_ty();
-
-        P(FnDecl {
-            inputs: inputs,
-            output: output,
-            variadic: false
-        })
-    }
-
     /// Parse the name and optional generic types of a function header.
     fn parse_fn_header(&mut self) -> (Ident, ast::Generics) {
         let id = self.parse_ident();

src/libsyntax/parse/token.rs

@@ -561,11 +561,11 @@ declare_special_idents_and_keywords! {
         (39,                         Virtual,    "virtual");
         (40,                         While,      "while");
         (41,                         Continue,   "continue");
-        (42,                         Proc,       "proc");
-        (43,                         Box,        "box");
-        (44,                         Const,      "const");
-        (45,                         Where,      "where");
+        (42,                         Box,        "box");
+        (43,                         Const,      "const");
+        (44,                         Where,      "where");
         'reserved:
+        (45,                         Proc,       "proc");
         (46,                         Alignof,    "alignof");
         (47,                         Become,     "become");
         (48,                         Offsetof,   "offsetof");

src/test/parse-fail/obsolete-proc.rs

@@ -10,8 +10,8 @@
 
 // Test that we generate obsolete syntax errors around usages of `proc`.
 
-fn foo(p: proc()) { } //~ ERROR obsolete syntax: the `proc` type
+fn foo(p: proc()) { } //~ ERROR `proc` is a reserved keyword
 
-fn bar() { proc() 1; } //~ ERROR obsolete syntax: `proc` expression
+fn bar() { proc() 1; }
 
-fn main() { }
+fn main() { }