Fix another bug when reaching macro expansion limit caused a stack overflow

This time without missing bindings.

Solve it by returning to the old ways, i.e. just throw the extra nodes away.

In other words, I acknowledge defeat.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/tools/rust-analyzer/crates/mbe/src/expander/transcriber.rs b/src/tools/rust-analyzer/crates/mbe/src/expander/transcriber.rs
index acab989437a..7710ea79389 100644
--- a/src/tools/rust-analyzer/crates/mbe/src/expander/transcriber.rs
+++ b/src/tools/rust-analyzer/crates/mbe/src/expander/transcriber.rs
@@ -448,6 +448,7 @@ fn expand_repeat(
     let mut counter = 0;
     let mut err = None;
 
+    let initial_restore_point = builder.restore_point();
     let mut restore_point = builder.restore_point();
     loop {
         let ExpandResult { value: (), err: e } =
@@ -465,6 +466,10 @@ fn expand_repeat(
 
         counter += 1;
         if counter == limit {
+            // FIXME: This is a bug here, we get here when we shouldn't, see https://github.com/rust-lang/rust-analyzer/issues/18910.
+            // If we don't restore we emit a lot of nodes which causes a stack overflow down the road. For now just ignore them,
+            // there is always an error here anyway.
+            builder.restore(initial_restore_point);
             err = Some(ExpandError::new(ctx.call_site, ExpandErrorKind::LimitExceeded));
             break;
         }