[build] incremental = true in .cargo/config.toml overrode the per-profile
defaults — including the standard release-profile default (false). This
caused two real issues:
1. --release builds wrote incremental compilation metadata to target/
for no runtime benefit (incremental's only payoff is between repeated
builds; ship-once release artifacts don't benefit).
2. sccache cannot cache incremental rustc output (documented limitation).
Rust hit rate was 0% as a direct result.
Removing the override restores standard cargo behavior:
- dev/test profiles: incremental = true (already set in [profile.dev]
and [profile.test] explicitly — unaffected)
- release/release-test/hft: incremental = false (cargo default)
The Argo CI template still sets CARGO_INCREMENTAL=0 explicitly as
defense-in-depth in case a future contributor re-adds the workspace
override.
05687ac941