Tweak macro parse errors when reaching EOF during macro call parse

- Add detail on origin of current parser when reaching EOF and stop
  saying "found <eof>" and point at the end of macro calls
- Handle empty `cfg_attr` attribute
- Reword empty `derive` attribute error

2 files changed, 6 insertions, 2 deletions

diff --git a/src/libsyntax_ext/asm.rs b/src/libsyntax_ext/asm.rs
index b8e89c3ecf8..704665e0a84 100644
--- a/src/libsyntax_ext/asm.rs
+++ b/src/libsyntax_ext/asm.rs
@@ -138,7 +138,11 @@ fn parse_inline_asm<'a>(
                 if p2.token != token::Eof {
                     let mut extra_tts = p2.parse_all_token_trees()?;
                     extra_tts.extend(tts[first_colon..].iter().cloned());
-                    p = parse::stream_to_parser(cx.parse_sess, extra_tts.into_iter().collect());
+                    p = parse::stream_to_parser(
+                        cx.parse_sess,
+                        extra_tts.into_iter().collect(),
+                        Some("inline assembly"),
+                    );
                 }
 
                 asm = s;
diff --git a/src/libsyntax_ext/deriving/custom.rs b/src/libsyntax_ext/deriving/custom.rs
index e73110717e9..975d96951dc 100644
--- a/src/libsyntax_ext/deriving/custom.rs
+++ b/src/libsyntax_ext/deriving/custom.rs
@@ -89,7 +89,7 @@ impl MultiItemModifier for ProcMacroDerive {
         let error_count_before = ecx.parse_sess.span_diagnostic.err_count();
         let msg = "proc-macro derive produced unparseable tokens";
 
-        let mut parser = parse::stream_to_parser(ecx.parse_sess, stream);
+        let mut parser = parse::stream_to_parser(ecx.parse_sess, stream, Some("proc-macro derive"));
         let mut items = vec![];
 
         loop {