Remove old slicing hacks and make new slicing work

2 files changed, 69 insertions, 144 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index f35f42d5aca..7824dacd3a1 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -63,7 +63,7 @@ use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
 use ast::{Visibility, WhereClause};
 use ast;
 use ast_util::{self, as_prec, ident_to_path, operator_prec};
-use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp, DUMMY_SP};
+use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp};
 use diagnostic;
 use ext::tt::macro_parser;
 use parse;
@@ -2103,22 +2103,6 @@ impl<'a> Parser<'a> {
         ExprIndex(expr, idx)
     }
 
-    pub fn mk_slice(&mut self,
-                    expr: P<Expr>,
-                    start: Option<P<Expr>>,
-                    end: Option<P<Expr>>,
-                    _mutbl: Mutability)
-                    -> ast::Expr_ {
-        // FIXME: we could give more accurate span info here.
-        let (lo, hi) = match (&start, &end) {
-            (&Some(ref s), &Some(ref e)) => (s.span.lo, e.span.hi),
-            (&Some(ref s), &None) => (s.span.lo, s.span.hi),
-            (&None, &Some(ref e)) => (e.span.lo, e.span.hi),
-            (&None, &None) => (DUMMY_SP.lo, DUMMY_SP.hi),
-        };
-        ExprIndex(expr, self.mk_expr(lo, hi, ExprRange(start, end)))
-    }
-
     pub fn mk_range(&mut self,
                     start: Option<P<Expr>>,
                     end: Option<P<Expr>>)
@@ -2550,87 +2534,28 @@ impl<'a> Parser<'a> {
               }
 
               // expr[...]
-              // Could be either an index expression or a slicing expression.
-              // Any slicing non-terminal can have a mutable version with `mut`
-              // after the opening square bracket.
+              // An index expression.
               token::OpenDelim(token::Bracket) => {
+                let bracket_pos = self.span.lo;
                 self.bump();
-                let mutbl = if self.eat_keyword(keywords::Mut) {
-                    MutMutable
+                if self.eat(&token::CloseDelim(token::Bracket)) {
+                    // No expression, expand to a FullRange
+                    let ix = {
+                        hi = self.last_span.hi;
+                        let range = ExprStruct(ident_to_path(mk_sp(lo, hi),
+                                                             token::special_idents::FullRange),
+                                               vec![],
+                                               None);
+                        self.mk_expr(bracket_pos, hi, range)
+                    };
+                    let index = self.mk_index(e, ix);
+                    e = self.mk_expr(lo, hi, index)
                 } else {
-                    MutImmutable
-                };
-                match self.token {
-                    // e.index(&FullRange)
-                    token::CloseDelim(token::Bracket) => {
-                        self.bump();
-                        hi = self.span.hi;
-                        let slice = self.mk_slice(e, None, None, mutbl);
-                        e = self.mk_expr(lo, hi, slice)
-                    }
-                    // e.index(&(0..e))
-                    token::DotDot => {
-                        self.bump();
-                        match self.token {
-                            // e.index(&(..))
-                            token::CloseDelim(token::Bracket) => {
-                                self.bump();
-                                hi = self.span.hi;
-                                let slice = self.mk_slice(e, None, None, mutbl);
-                                e = self.mk_expr(lo, hi, slice);
-
-                                self.span_err(e.span, "incorrect slicing expression: `[..]`");
-                                self.span_note(e.span,
-                                    "use `expr.index(&FullRange)` to construct a slice of the whole of expr");
-                            }
-                            // e.index(&(0..e))
-                            _ => {
-                                hi = self.span.hi;
-                                let e2 = self.parse_expr();
-                                self.commit_expr_expecting(&*e2, token::CloseDelim(token::Bracket));
-                                let slice = self.mk_slice(e, None, Some(e2), mutbl);
-                                e = self.mk_expr(lo, hi, slice)
-                            }
-                        }
-                    }
-                    // e[e] | e.index(&(e..)) | e.index(&(e..e))
-                    _ => {
-                        let ix = self.parse_expr_res(RESTRICTION_NO_DOTS);
-                        match self.token {
-                            // e.index(&(e..)) | e.index(&(e..e))
-                            token::DotDot => {
-                                self.bump();
-                                let e2 = match self.token {
-                                    // e.index(&(e..))
-                                    token::CloseDelim(token::Bracket) => {
-                                        self.bump();
-                                        None
-                                    }
-                                    // e.index(&(e..e))
-                                    _ => {
-                                        let e2 = self.parse_expr_res(RESTRICTION_NO_DOTS);
-                                        self.commit_expr_expecting(&*e2,
-                                            token::CloseDelim(token::Bracket));
-                                        Some(e2)
-                                    }
-                                };
-                                hi = self.span.hi;
-                                let slice = self.mk_slice(e, Some(ix), e2, mutbl);
-                                e = self.mk_expr(lo, hi, slice)
-                            }
-                            // e[e]
-                            _ => {
-                                if mutbl == ast::MutMutable {
-                                    self.span_err(e.span,
-                                                  "`mut` keyword is invalid in index expressions");
-                                }
-                                hi = self.span.hi;
-                                self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket));
-                                let index = self.mk_index(e, ix);
-                                e = self.mk_expr(lo, hi, index)
-                            }
-                        }
-                    }
+                    let ix = self.parse_expr();
+                    hi = self.span.hi;
+                    self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket));
+                    let index = self.mk_index(e, ix);
+                    e = self.mk_expr(lo, hi, index)
                 }
               }
 
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index ca683a56472..ada463a40cb 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -515,66 +515,66 @@ declare_special_idents_and_keywords! {
         (9,                          unnamed_field,          "<unnamed_field>");
         (10,                         type_self,              "Self");
         (11,                         prelude_import,         "prelude_import");
+        (12,                         FullRange,              "FullRange");
     }
 
     pub mod keywords {
         // These ones are variants of the Keyword enum
 
         'strict:
-        (12,                         As,         "as");
-        (13,                         Break,      "break");
-        (14,                         Crate,      "crate");
-        (15,                         Else,       "else");
-        (16,                         Enum,       "enum");
-        (17,                         Extern,     "extern");
-        (18,                         False,      "false");
-        (19,                         Fn,         "fn");
-        (20,                         For,        "for");
-        (21,                         If,         "if");
-        (22,                         Impl,       "impl");
-        (23,                         In,         "in");
-        (24,                         Let,        "let");
-        (25,                         Loop,       "loop");
-        (26,                         Match,      "match");
-        (27,                         Mod,        "mod");
-        (28,                         Move,       "move");
-        (29,                         Mut,        "mut");
-        (30,                         Pub,        "pub");
-        (31,                         Ref,        "ref");
-        (32,                         Return,     "return");
+        (13,                         As,         "as");
+        (14,                         Break,      "break");
+        (15,                         Crate,      "crate");
+        (16,                         Else,       "else");
+        (17,                         Enum,       "enum");
+        (18,                         Extern,     "extern");
+        (19,                         False,      "false");
+        (20,                         Fn,         "fn");
+        (21,                         For,        "for");
+        (22,                         If,         "if");
+        (23,                         Impl,       "impl");
+        (24,                         In,         "in");
+        (25,                         Let,        "let");
+        (26,                         Loop,       "loop");
+        (27,                         Match,      "match");
+        (28,                         Mod,        "mod");
+        (29,                         Move,       "move");
+        (30,                         Mut,        "mut");
+        (31,                         Pub,        "pub");
+        (32,                         Ref,        "ref");
+        (33,                         Return,     "return");
         // Static and Self are also special idents (prefill de-dupes)
         (super::STATIC_KEYWORD_NAME_NUM, Static, "static");
         (super::SELF_KEYWORD_NAME_NUM,   Self,   "self");
-        (33,                         Struct,     "struct");
+        (34,                         Struct,     "struct");
         (super::SUPER_KEYWORD_NAME_NUM, Super,   "super");
-        (34,                         True,       "true");
-        (35,                         Trait,      "trait");
-        (36,                         Type,       "type");
-        (37,                         Unsafe,     "unsafe");
-        (38,                         Use,        "use");
-        (39,                         Virtual,    "virtual");
-        (40,                         While,      "while");
-        (41,                         Continue,   "continue");
-        (42,                         Proc,       "proc");
-        (43,                         Box,        "box");
-        (44,                         Const,      "const");
-        (45,                         Where,      "where");
-
+        (35,                         True,       "true");
+        (36,                         Trait,      "trait");
+        (37,                         Type,       "type");
+        (38,                         Unsafe,     "unsafe");
+        (39,                         Use,        "use");
+        (40,                         Virtual,    "virtual");
+        (41,                         While,      "while");
+        (42,                         Continue,   "continue");
+        (43,                         Proc,       "proc");
+        (44,                         Box,        "box");
+        (45,                         Const,      "const");
+        (46,                         Where,      "where");
         'reserved:
-        (46,                         Alignof,    "alignof");
-        (47,                         Be,         "be");
-        (48,                         Offsetof,   "offsetof");
-        (49,                         Priv,       "priv");
-        (50,                         Pure,       "pure");
-        (51,                         Sizeof,     "sizeof");
-        (52,                         Typeof,     "typeof");
-        (53,                         Unsized,    "unsized");
-        (54,                         Yield,      "yield");
-        (55,                         Do,         "do");
-        (56,                         Abstract,   "abstract");
-        (57,                         Final,      "final");
-        (58,                         Override,   "override");
-        (59,                         Macro,      "macro");
+        (47,                         Alignof,    "alignof");
+        (48,                         Be,         "be");
+        (49,                         Offsetof,   "offsetof");
+        (50,                         Priv,       "priv");
+        (51,                         Pure,       "pure");
+        (52,                         Sizeof,     "sizeof");
+        (53,                         Typeof,     "typeof");
+        (54,                         Unsized,    "unsized");
+        (55,                         Yield,      "yield");
+        (56,                         Do,         "do");
+        (57,                         Abstract,   "abstract");
+        (58,                         Final,      "final");
+        (59,                         Override,   "override");
+        (60,                         Macro,      "macro");
     }
 }