rustc: For one-tuples, make parsing and printing the type work

and add a test to reflect-visit-data

2 files changed, 14 insertions, 2 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index b5c68d6715e..a9b455c3304 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -576,12 +576,21 @@ pub impl Parser {
                 self.bump();
                 ty_nil
             } else {
+                // (t) is a parenthesized ty
+                // (t,) is the type of a tuple with only one field,
+                // of type t
                 let mut ts = ~[self.parse_ty(false)];
+                let mut one_tuple = false;
                 while self.token == token::COMMA {
                     self.bump();
-                    ts.push(self.parse_ty(false));
+                    if self.token != token::RPAREN {
+                        ts.push(self.parse_ty(false));
+                    }
+                    else {
+                        one_tuple = true;
+                    }
                 }
-                let t = if vec::len(ts) == 1u { ts[0].node }
+                let t = if ts.len() == 1 && !one_tuple { ts[0].node }
                 else { ty_tup(ts) };
                 self.expect(token::RPAREN);
                 t
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 8f2ad6ecb90..ccb3947f834 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -414,6 +414,9 @@ pub fn print_type_ex(s: @ps, &&ty: @ast::Ty, print_colons: bool) {
       ast::ty_tup(elts) => {
         popen(s);
         commasep(s, inconsistent, elts, print_type);
+        if elts.len() == 1 {
+            word(s.s, ~",");
+        }
         pclose(s);
       }
       ast::ty_bare_fn(f) => {