diff options
Diffstat (limited to 'src/libsyntax')
| -rw-r--r-- | src/libsyntax/ext/expand.rs | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs index ce326b728df..41ed90fb94e 100644 --- a/src/libsyntax/ext/expand.rs +++ b/src/libsyntax/ext/expand.rs @@ -387,6 +387,8 @@ impl<'a, 'b> MacroExpander<'a, 'b> { add_derived_markers(&mut self.cx, item.span(), &traits, item.clone()); let derives = derives.entry(invoc.expansion_data.mark).or_default(); + derives.reserve(traits.len()); + invocations.reserve(traits.len()); for path in &traits { let mark = Mark::fresh(self.cx.current_expansion.mark); derives.push(mark); |