dt-list-add-empty — empty List + add
Status: measured
Claim
Growable <int>[] + add is slower than List.filled + index writes (~4.40×) on Dart 3.13.7.
How measured
-
Harness:
examples/bench/evidence_dt.dart -
N=200000
-
Raw lines:
dt-list-add-empty.jsonl
Runtime (this evidence file)
| Field | Value |
|---|---|
| When | 2026-10-22 Asia/Shanghai (JSONL ts is UTC) |
| dart | 3.13.6 |
Median before (add_loop_empty) | 9.505 ms |
Median after (list_filled) | 2.158 ms |
| ratio before/after | ~4.40× |
Lint mapping
dartperf-lint dt-list-add-empty: keep default severity.
Limits
- Default stays off.