Fix macro call site spans

Author: jseyfried

src/libsyntax/ext/base.rs

@@ -602,22 +602,6 @@ impl<'a> ExtCtxt<'a> {
     }
     pub fn backtrace(&self) -> ExpnId { self.backtrace }
 
-    /// Original span that caused the current exapnsion to happen.
-    pub fn original_span(&self) -> Span {
-        let mut expn_id = self.backtrace;
-        let mut call_site = None;
-        loop {
-            match self.codemap().with_expn_info(expn_id, |ei| ei.map(|ei| ei.call_site)) {
-                None => break,
-                Some(cs) => {
-                    call_site = Some(cs);
-                    expn_id = cs.expn_id;
-                }
-            }
-        }
-        call_site.expect("missing expansion backtrace")
-    }
-
     /// Returns span for the macro which originally caused the current expansion to happen.
     ///
     /// Stops backtracing at include! boundary.

src/libsyntax/ext/expand.rs

@@ -215,6 +215,7 @@ fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attr
             return None;
         };
 
+        let call_site = fld.new_span(call_site);
         let ident = ident.unwrap_or(keywords::Invalid.ident());
         match *extension {
             NormalTT(ref expandfun, exp_span, allow_internal_unstable) => {
@@ -234,14 +235,8 @@ fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attr
                     },
                 });
 
-                // The span that we pass to the expanders we want to
-                // be the root of the call stack. That's the most
-                // relevant span and it's the actual invocation of
-                // the macro.
-                let mac_span = fld.cx.original_span();
-
                 let marked_tts = mark_tts(&tts[..], mark);
-                Some(expandfun.expand(fld.cx, mac_span, &marked_tts))
+                Some(expandfun.expand(fld.cx, call_site, &marked_tts))
             }
 
             IdentTT(ref expander, tt_span, allow_internal_unstable) => {