Merge #1192

1192: Add mbe expand limit and poision macro set r=maklad a=edwin0cheng

As discussed in Zulip, this PR add a token expansion limit in `parse_macro` and a "poison" macro set in `CrateDefMap` to prevent stack over flow and limit a mbe macro size.

Note:
Right now it only handle a poison macro in a single crate, such that if other crate try to call that macro, the whole process will do again until it became poisoned in that crate.


Co-authored-by: Edwin Cheng <[email protected]>

1 files changed, 16 insertions, 0 deletions

diff --git a/crates/ra_tt/src/lib.rs b/crates/ra_tt/src/lib.rs
index 0b0b9b4d2..62c5ac52a 100644
--- a/crates/ra_tt/src/lib.rs
+++ b/crates/ra_tt/src/lib.rs
@@ -149,3 +149,19 @@ impl fmt::Display for Punct {
         fmt::Display::fmt(&self.char, f)
     }
 }
+
+impl Subtree {
+    /// Count the number of tokens recursively
+    pub fn count(&self) -> usize {
+        let children_count = self
+            .token_trees
+            .iter()
+            .map(|c| match c {
+                TokenTree::Subtree(c) => c.count(),
+                _ => 0,
+            })
+            .sum::<usize>();
+
+        self.token_trees.len() + children_count
+    }
+}