Use '..' as slice wildcard in vectors

2 files changed, 35 insertions, 12 deletions

diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 8fb96a3e07a..2af6d141aa1 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -40,7 +40,8 @@ pub enum ObsoleteSyntax {
     ObsoleteEmptyImpl,
     ObsoleteLoopAsContinue,
     ObsoleteEnumWildcard,
-    ObsoleteStructWildcard
+    ObsoleteStructWildcard,
+    ObsoleteVecDotDotWildcard
 }
 
 impl to_bytes::IterBytes for ObsoleteSyntax {
@@ -123,6 +124,10 @@ impl ParserObsoleteMethods for Parser {
                 "struct wildcard",
                 "use `..` instead of `_` for matching trailing struct fields"
             ),
+            ObsoleteVecDotDotWildcard => (
+                "vec slice wildcard",
+                "use `..` instead of `.._` for matching slices"
+            ),
         };
 
         self.report(sp, kind, kind_str, desc);
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index ea861305d9f..1b2e18f3ca5 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -43,7 +43,7 @@ use ast::{MutImmutable, MutMutable, mac_, mac_invoc_tt, matcher, match_nontermin
 use ast::{match_seq, match_tok, method, mt, BiMul, Mutability};
 use ast::{named_field, UnNeg, noreturn, UnNot, Pat, PatBox, PatEnum};
 use ast::{PatIdent, PatLit, PatRange, PatRegion, PatStruct};
-use ast::{PatTup, PatUniq, PatWild, private};
+use ast::{PatTup, PatUniq, PatWild, PatWildMulti, private};
 use ast::{BiRem, required};
 use ast::{ret_style, return_val, BiShl, BiShr, Stmt, StmtDecl};
 use ast::{StmtExpr, StmtSemi, StmtMac, struct_def, struct_field};
@@ -2724,17 +2724,35 @@ impl Parser {
                 }
             }
 
-            let subpat = self.parse_pat();
             if is_slice {
-                match subpat {
-                    @ast::Pat { node: PatWild, _ } => (),
-                    @ast::Pat { node: PatIdent(_, _, _), _ } => (),
-                    @ast::Pat { span, _ } => self.span_fatal(
-                        span, "expected an identifier or `_`"
-                    )
+                if *self.token == token::COMMA || *self.token == token::RBRACKET {
+                    slice = Some(@ast::Pat {
+                        id: ast::DUMMY_NODE_ID,
+                        node: PatWildMulti,
+                        span: *self.span,
+                    })
+                } else {
+                    let subpat = self.parse_pat();
+                    match subpat {
+                        @ast::Pat { id, node: PatWild, span } => {
+                            // NOTE #5830 activate after snapshot
+                            // self.obsolete(*self.span, ObsoleteVecDotDotWildcard);
+                            slice = Some(@ast::Pat {
+                                id: id,
+                                node: PatWildMulti,
+                                span: span
+                            })
+                        },
+                        @ast::Pat { node: PatIdent(_, _, _), _ } => {
+                            slice = Some(subpat);
+                        }
+                        @ast::Pat { span, _ } => self.span_fatal(
+                            span, "expected an identifier or nothing"
+                        )
+                    }
                 }
-                slice = Some(subpat);
             } else {
+                let subpat = self.parse_pat();
                 if before_slice {
                     before.push(subpat);
                 } else {
@@ -2757,7 +2775,7 @@ impl Parser {
 
             etc = *self.token == token::UNDERSCORE || *self.token == token::DOTDOT;
             if *self.token == token::UNDERSCORE {
-                // FIXME #5830 activate after snapshot
+                // NOTE #5830 activate after snapshot
                 // self.obsolete(*self.span, ObsoleteStructWildcard);
             }
             if etc {
@@ -3031,7 +3049,7 @@ impl Parser {
                                 // This is a "top constructor only" pat
                                 self.bump();
                                 if is_star {
-                                    // FIXME #5830 activate after snapshot
+                                    // NOTE #5830 activate after snapshot
                                     // self.obsolete(*self.span, ObsoleteEnumWildcard);
                                 }
                                 self.bump();