Slightly improved macro diagnostics + Indentation fixes

src/libsyntax/ext/tt/macro_parser.rs

@@ -401,7 +401,7 @@ pub fn parse(sess: &ParseSess,
                         }
                     }
                     TtToken(sp, SubstNt(..)) => {
-                        return Error(sp, "Cannot transcribe in macro LHS".to_string())
+                        return Error(sp, "missing fragment specifier".to_string())
                     }
                     seq @ TtDelimited(..) | seq @ TtToken(_, DocComment(..)) => {
                         let lower_elts = mem::replace(&mut ei.top_elts, Tt(seq));
@@ -440,20 +440,24 @@ pub fn parse(sess: &ParseSess,
         } else {
             if (!bb_eis.is_empty() && !next_eis.is_empty())
                 || bb_eis.len() > 1 {
-                let nts = bb_eis.iter().map(|ei| {
+                let nts = bb_eis.iter().map(|ei| match ei.top_elts.get_tt(ei.idx) {
-                    match ei.top_elts.get_tt(ei.idx) {
                     TtToken(_, MatchNt(bind, name, _, _)) => {
                         format!("{} ('{}')", name, bind)
                     }
                     _ => panic!()
-                    } }).collect::<Vec<String>>().join(" or ");
+                }).collect::<Vec<String>>().join(" or ");
+
                 return Error(sp, format!(
-                    "local ambiguity: multiple parsing options: \
+                    "local ambiguity: multiple parsing options: {}",
-                     built-in NTs {} or {} other options.",
+                    match next_eis.len() {
-                    nts, next_eis.len()).to_string());
+                        0 => format!("built-in NTs {}.", nts),
+                        1 => format!("built-in NTs {} or 1 other option.", nts),
+                        n => format!("built-in NTs {} or {} other options.", nts, n),
+                    }
+                ))
             } else if bb_eis.is_empty() && next_eis.is_empty() {
                 return Failure(sp, format!("no rules expected the token `{}`",
-                            pprust::token_to_string(&tok)).to_string());
+                            pprust::token_to_string(&tok)));
             } else if !next_eis.is_empty() {
                 /* Now process the next token */
                 while !next_eis.is_empty() {
@@ -522,7 +526,7 @@ pub fn parse_nt(p: &mut Parser, sp: Span, name: &str) -> Nonterminal {
         },
         "path" => {
             token::NtPath(Box::new(panictry!(p.parse_path(LifetimeAndTypesWithoutColons))))
-      }
+        },
         "meta" => token::NtMeta(p.parse_meta_item()),
         _ => {
             panic!(p.span_fatal_help(sp,

src/test/compile-fail/macro-match-nonterminal.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-macro_rules! test { ($a, $b) => (()); } //~ ERROR Cannot transcribe
+macro_rules! test { ($a, $b) => (()); } //~ ERROR missing fragment
 
 fn main() {
     test!()