From dfab545d5df974d4a50325695a25f763b7613baf Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Wed, 24 Apr 2019 03:00:59 +0800
Subject: [PATCH] Add more information on macro rules fail to parse

---
 crates/ra_hir/src/ids.rs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index c7849c995b0..b0e9b1f9af7 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -128,8 +128,14 @@ fn from(macro_call_id: MacroCallId) -> HirFileId {
 pub(crate) fn macro_def_query(db: &impl DefDatabase, id: MacroDefId) -> Option<Arc<MacroRules>> {
     let macro_call = id.0.to_node(db);
     let arg = macro_call.token_tree()?;
-    let (tt, _) = mbe::ast_to_token_tree(arg)?;
-    let rules = MacroRules::parse(&tt).ok()?;
+    let (tt, _) = mbe::ast_to_token_tree(arg).or_else(|| {
+        log::warn!("fail on macro_def to token tree: {:#?}", arg);
+        None
+    })?;
+    let rules = MacroRules::parse(&tt).ok().or_else(|| {
+        log::warn!("fail on macro_def parse: {:#?}", tt);
+        None
+    })?;
     Some(Arc::new(rules))
 }