clippy: 33 deny lints + fix 2735 violations across workspace

[Jarred-Sumner]

Adds 45 deny-level clippy lints + dead_code/unused_*/unreachable_* to [workspace.lints], a clippy.toml routing std::{fs,sync,collections,process,env} and println!/eprintln! through bun_* wrappers, and fixes the resulting violations across the workspace. Net −6.2K LOC of dead code.

Lint set

Soundness / leak prevention — undocumented_unsafe_blocks, not_unsafe_ptr_arg_deref, mem_forget, cast_ptr_alignment, transmute_ptr_to_ptr, as_ptr_cast_mut, drop_non_drop, uninit_vec

Performance — redundant_clone, unnecessary_to_owned, needless_collect, or_fun_call, assigning_clones, implicit_clone, iter_overeager_cloned, map_clone, trivially_copy_pass_by_ref, large_types_passed_by_value, large_enum_variant, large_stack_frames, vec_init_then_push, format_collect, manual_memcpy, needless_pass_by_value

Clarity — unnecessary_unwrap, derive_partial_eq_without_eq, derivable_impls, clone_on_ref_ptr, if_same_then_else, todo, unimplemented, dbg_macro, clone_on_copy, useless_conversion, manual_swap, mem_replace_option_with_none, redundant_locals, manual_c_str_literals, precedence, implicit_saturating_sub, ptr_eq

Disallowed — disallowed_{methods,types,macros} configured in clippy.toml: std::sync::{Mutex,RwLock} + parking_lot::* → bun_threading; std::fs::* → bun_sys; std::collections::Hash{Map,Set} → bun_collections (wyhash); std::process::Command → bun_sys::process; println!/eprintln! → bun_core::output; std::env::var → bun_core::env; std::thread::spawn → bun_threading; std::mem::zeroed banned.

rustc — dead_code, unused_imports, unused_variables, unused_mut, unused_assignments, unused_macros, unreachable_code, unreachable_patterns denied workspace-wide. ~505 inline #[allow(unused/dead_code/unreachable_*)] attrs and ~90 crate-level #![allow(unused, ...)] words removed; the items they were hiding deleted or #[cfg]'d to the platform/profile they're live on.

31 default-warn lints explicitly allow'd (Zig-port style).

Notable fixes

• 1,341 // SAFETY: comments added immediately above unsafe { blocks, each stating the actual invariant.
• 156 not_unsafe_ptr_arg_deref: safe fn(p: *mut T) that deref p → unsafe fn with # Safety doc, or param changed to NonNull<T>/&T. generate-host-exports.ts already detected pub unsafe fn and wraps the thunk body — regenerated.
• 47 mem_forget → ManuallyDrop / Box::into_raw / Arc::into_raw / Box::leak. enum_map! (8 sites) replaced with EnumMap::from_fn.
• 840 signature changes (trivially_copy_pass_by_ref + needless_pass_by_value + large_types_passed_by_value): &Copy → Copy, owned-but-only-read → &T. All callers updated.
• protocol::IsCompatible + calc_protocol_forwarders!: Browsers → &Browsers.
• SinkHandler/JsSinkType/impl_sink_handler!/VTable: data: StreamResult → &StreamResult.
• ParserLike::log(&self) -> &mut Log (mut_from_ref): replaced trait method with log_ptr(&self) -> NonNull<Log>.
• tick_while_paused: &mut bool → *const bool + read_volatile() — C++ writes through an aliased pointer during tick(), so &mut was an aliasing violation, not just a lint.
• flush_category! (css border): 152KB stack frame → #[inline(never)] helpers.
• cppbind.ts: &x as *const T → core::ptr::from_ref; // SAFETY: above generated unsafe { raw::… } calls.
• Dead-code deletions: ~650 lines of duplicate draft unicode.rs impls; ~500 lines of unused resolver/fs.rs types; ~250 lines shell_parser; ~180 lines package_json reverse-resolution; 256-line dead name_static; dead FFI extern decls (Rust→C++ imports nothing calls).
• Platform/profile cfg-gating: ~60 files where an item is live only on one target/profile (#[cfg(target_os = ...)] / #[cfg(debug_assertions)]).

CI

• .github/workflows/clippy.yml — bun run rust:clippy with inline PR annotations via .github/rust-matcher.json.
• .github/workflows/miri.yml — bun run rust:miri (Tree Borrows) on the FFI-free crate set.

Exceptions (the only #![allow]s added)

• 4× build.rs: disallowed_{methods,types,macros} — build scripts run on the host before bun_* crates exist.
• bun_alloc/lib.rs: disallowed_types — T0 foundation crate; bun_threading/bun_collections depend on it.
• #[allow] inside macro_rules!/quote!{} bodies are preserved — they suppress lints in emitted code that varies per call site.

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cargo clippy --workspace --no-deps: 0 errors. bun run rust:check-all: 10/10. bun bd: builds.