Auto merge of #30598 - est31:macro_export_help_note, r=Manishearth

The current help message is too much about "normal" macros to be used
as general message. Keep it for normal macros, and add custom help and
error messages for macro definitions.

1 files changed, 17 insertions, 5 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index a65a6b4a9da..db746af998d 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -67,7 +67,7 @@ use parse::classify;
 use parse::common::{SeqSep, seq_sep_none, seq_sep_trailing_allowed};
 use parse::lexer::{Reader, TokenAndSpan};
 use parse::obsolete::{ParserObsoleteMethods, ObsoleteSyntax};
-use parse::token::{self, MatchNt, SubstNt, SpecialVarNt, InternedString};
+use parse::token::{self, intern, MatchNt, SubstNt, SpecialVarNt, InternedString};
 use parse::token::{keywords, special_idents, SpecialMacroVar};
 use parse::{new_sub_parser_from_file, ParseSess};
 use util::parser::{AssocOp, Fixity};
@@ -4622,10 +4622,22 @@ impl<'a> Parser<'a> {
     fn complain_if_pub_macro(&mut self, visa: Visibility, span: Span) {
         match visa {
             Public => {
-                self.diagnostic().struct_span_err(span, "can't qualify macro invocation with `pub`")
-                                 .fileline_help(span, "try adjusting the macro to put `pub` inside \
-                                                       the invocation")
-                                 .emit();
+                let is_macro_rules: bool = match self.token {
+                    token::Ident(sid, _) => sid.name == intern("macro_rules"),
+                    _ => false,
+                };
+                if is_macro_rules {
+                    self.diagnostic().struct_span_err(span, "can't qualify macro_rules \
+                                                             invocation with `pub`")
+                                     .fileline_help(span, "did you mean #[macro_export]?")
+                                     .emit();
+                } else {
+                    self.diagnostic().struct_span_err(span, "can't qualify macro \
+                                                             invocation with `pub`")
+                                     .fileline_help(span, "try adjusting the macro to put `pub` \
+                                                           inside the invocation")
+                                     .emit();
+                }
             }
             Inherited => (),
         }