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

1 files changed, 8 insertions, 1 deletions

diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index 2f75a8c9db5..48948e4d0d7 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -278,7 +278,14 @@ impl Attribute {
     pub fn parse<'a, T, F>(&self, sess: &'a ParseSess, mut f: F) -> PResult<'a, T>
         where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
     {
-        let mut parser = Parser::new(sess, self.tokens.clone(), None, false, false);
+        let mut parser = Parser::new(
+            sess,
+            self.tokens.clone(),
+            None,
+            false,
+            false,
+            Some("attribute"),
+        );
         let result = f(&mut parser)?;
         if parser.token != token::Eof {
             parser.unexpected()?;