From 14398f29290b0d96dbe60f329b69062442eefb33 Mon Sep 17 00:00:00 2001
From: P1start <rewi-github@whanau.org>
Date: Mon, 27 Oct 2014 17:43:38 +1300
Subject: [PATCH] Add a message for when a `.` follows a macro invocation

---
 src/libsyntax/parse/parser.rs                      | 10 ++++++++++
 src/test/compile-fail/macro-invocation-dot-help.rs | 14 ++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 src/test/compile-fail/macro-invocation-dot-help.rs

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index d9dd37fcb4f..f04f9efd7a7 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -3592,6 +3592,16 @@ fn check_expected_item(p: &mut Parser, attrs: &[Attribute]) {
             let hi = self.span.hi;
 
             if id.name == token::special_idents::invalid.name {
+                if self.token == token::Dot {
+                    let span = self.span;
+                    let token_string = self.this_token_to_string();
+                    self.span_err(span,
+                                  format!("expected statement, found `{}`",
+                                          token_string).as_slice());
+                    let mac_span = mk_sp(lo, hi);
+                    self.span_help(mac_span, "try parenthesizing this macro invocation");
+                    self.abort_if_errors();
+                }
                 P(spanned(lo, hi, StmtMac(
                     spanned(lo, hi, MacInvocTT(pth, tts, EMPTY_CTXT)), false)))
             } else {
diff --git a/src/test/compile-fail/macro-invocation-dot-help.rs b/src/test/compile-fail/macro-invocation-dot-help.rs
new file mode 100644
index 00000000000..bd45b76dd5a
--- /dev/null
+++ b/src/test/compile-fail/macro-invocation-dot-help.rs
@@ -0,0 +1,14 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    foo!() //~ HELP try parenthesizing this macro invocation
+    .bar //~ ERROR expected statement
+}