Clear `inner_attr_ranges` regularly.

There's a comment saying we don't do it for performance reasons, but it
doesn't actually affect performance.

The commit also tweaks the control flow, to make clearer that two code
paths are mutually exclusive.

1 files changed, 3 insertions, 8 deletions

diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index 38f18022e3c..e9aece13b2e 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -352,15 +352,10 @@ impl<'a> Parser<'a> {
             let target = AttrsTarget { attrs: final_attrs.iter().cloned().collect(), tokens };
             self.capture_state.replace_ranges.push((start_pos..end_pos, Some(target)));
             self.capture_state.replace_ranges.extend(inner_attr_replace_ranges);
-        }
-
-        // Only clear our `replace_ranges` when we're finished capturing entirely.
-        if matches!(self.capture_state.capturing, Capturing::No) {
+        } else if matches!(self.capture_state.capturing, Capturing::No) {
+            // Only clear the ranges once we've finished capturing entirely.
             self.capture_state.replace_ranges.clear();
-            // We don't clear `inner_attr_ranges`, as doing so repeatedly
-            // had a measurable performance impact. Most inner attributes that
-            // we insert will get removed - when we drop the parser, we'll free
-            // up the memory used by any attributes that we didn't remove from the map.
+            self.capture_state.inner_attr_ranges.clear();
         }
         Ok(ret)
     }