From 2e7afd73676f95ad3b944788c4798ad538a5edd2 Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Thu, 19 May 2016 10:30:34 +0000
Subject: [PATCH] Improve diagnostics

---
 src/libsyntax/ext/expand.rs | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index b2ebe0e0145..6c22fe4c8bc 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -272,11 +272,9 @@ fn expand_mac_invoc<T: MacroGenerable>(mac: ast::Mac, span: Span, fld: &mut Macr
                 let parsed = match opt_parsed {
                     Some(e) => e,
                     None => {
-                        fld.cx.span_err(
-                            pth.span,
-                            &format!("non-expression macro in expression position: {}",
-                                    extname
-                                    ));
+                        let msg = format!("non-{kind} macro in {kind} position: {name}",
+                                          name = extname, kind = T::kind_name());
+                        fld.cx.span_err(pth.span, &msg);
                         return None;
                     }
                 };