Always implement Debug
#4624
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Always implement Debug
#4624
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sigh ctest bugs... |
Currently `Debug` implementations are gated behind the `extra-traits` feature. My understanding is that historically, this was for two reasons: 1. `Debug` implementations for unions were unsound 2. Concerns about compile time The first was resolved a while ago by adding a "manual derive" opaque implementation, in 6faa521 ("fix: make Debug impl for unions opaque"). Regarding the second reason, compile times for the current `main` on my machine are (cleaning in between, with the 2025-08-06 nightly): $ cargo build -p libc Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.79s $ cargo build -p libc --release Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `release` profile [optimized] target(s) in 0.64s $ cargo build -p libc --features extra_traits Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.08s $ cargo build -p libc --features extra_traits --release Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `release` profile [optimized] target(s) in 0.85s And with this patch applied: $ cargo build -p libc Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.89s $ cargo build -p libc --release Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `release` profile [optimized] target(s) in 0.70s $ cargo build -p libc --features extra_traits Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.15s $ cargo build -p libc --features extra_traits --release Compiling libc v1.0.0-alpha.1 (~/rust-libc) Finished `release` profile [optimized] target(s) in 0.86s That is a microbenchmark but it shows that there probably isn't anything to worry about. Thus, remove the `Debug` implementation from the `feature = "extra_traitts"` gating. Another advantage of doing this is that it should allow many crates to remove the enable for `extra_traits`, giving us a better idea of who wants `Debug` vs. who is actually using the `Eq`/`Hash` implementations. Link: rust-lang#3880
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@rustbot blocked |
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Currently
Debugimplementations are gated behind theextra-traitsfeature. My understanding is that historically, this was for two reasons:Debugimplementations for unions were unsoundThe first was resolved a while ago by adding a "manual derive" opaque implementation, in 6faa521 ("fix: make Debug impl for unions opaque"). Regarding the second reason, compile times for the current
mainon my machine are (cleaning in between, with the 2025-08-06 nightly):And with this patch applied:
That is a microbenchmark but it shows that there probably isn't anything to worry about.
Thus, remove the
Debugimplementation from thefeature = "extra_traitts"gating.Another advantage of doing this is that it should allow many crates to remove the enable for
extra_traits, giving us a better idea of who wantsDebugvs. who is actually using theEq/Hashimplementations.Link: #3880