rollup merge of #20057: nick29581/array-syntax

This does NOT break any existing programs because the `[_, ..n]` syntax is also supported.

Part of #19999

r? @nikomatsakis

2 files changed, 12 insertions, 4 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 52aa609aeaf..19af118b190 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1545,7 +1545,7 @@ impl<'a> Parser<'a> {
             self.expect(&token::OpenDelim(token::Bracket));
             let t = self.parse_ty_sum();
 
-            // Parse the `, ..e` in `[ int, ..e ]`
+            // Parse the `; e` in `[ int; e ]`
             // where `e` is a const expression
             let t = match self.maybe_parse_fixed_vstore() {
                 None => TyVec(t),
@@ -1713,6 +1713,9 @@ impl<'a> Parser<'a> {
             self.bump();
             self.bump();
             Some(self.parse_expr())
+        } else if self.check(&token::Semi) {
+            self.bump();
+            Some(self.parse_expr())
         } else {
             None
         }
@@ -2259,6 +2262,12 @@ impl<'a> Parser<'a> {
                         let count = self.parse_expr();
                         self.expect(&token::CloseDelim(token::Bracket));
                         ex = ExprRepeat(first_expr, count);
+                    } else if self.check(&token::Semi) {
+                        // Repeating vector syntax: [ 0; 512 ]
+                        self.bump();
+                        let count = self.parse_expr();
+                        self.expect(&token::CloseDelim(token::Bracket));
+                        ex = ExprRepeat(first_expr, count);
                     } else if self.check(&token::Comma) {
                         // Vector with two or more elements.
                         self.bump();
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index f27a476dbdd..a9717a526ad 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -755,7 +755,7 @@ impl<'a> State<'a> {
             ast::TyFixedLengthVec(ref ty, ref v) => {
                 try!(word(&mut self.s, "["));
                 try!(self.print_type(&**ty));
-                try!(word(&mut self.s, ", .."));
+                try!(word(&mut self.s, "; "));
                 try!(self.print_expr(&**v));
                 try!(word(&mut self.s, "]"));
             }
@@ -1531,8 +1531,7 @@ impl<'a> State<'a> {
                 try!(self.ibox(indent_unit));
                 try!(word(&mut self.s, "["));
                 try!(self.print_expr(&**element));
-                try!(word(&mut self.s, ","));
-                try!(word(&mut self.s, ".."));
+                try!(self.word_space(";"));
                 try!(self.print_expr(&**count));
                 try!(word(&mut self.s, "]"));
                 try!(self.end());