From 6d0df84f6f879feb2211f8f61351a4669d2397e0 Mon Sep 17 00:00:00 2001 From: Jirka Vebr Date: Thu, 16 Feb 2023 16:08:28 +0100 Subject: [PATCH] Add the `transmute_int_to_non_zero` lint --- CHANGELOG.md | 1 + clippy_lints/src/declared_lints.rs | 1 + clippy_lints/src/transmute/mod.rs | 28 ++++++++ .../transmute/transmute_int_to_non_zero.rs | 61 ++++++++++++++++++ tests/ui/transmute_int_to_non_zero.rs | 41 ++++++++++++ tests/ui/transmute_int_to_non_zero.stderr | 64 +++++++++++++++++++ 6 files changed, 196 insertions(+) create mode 100644 clippy_lints/src/transmute/transmute_int_to_non_zero.rs create mode 100644 tests/ui/transmute_int_to_non_zero.rs create mode 100644 tests/ui/transmute_int_to_non_zero.stderr diff --git a/CHANGELOG.md b/CHANGELOG.md index 73ae215ce..9138a4fb9 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -4794,6 +4794,7 @@ Released 2018-09-13 [`transmute_int_to_bool`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_int_to_bool [`transmute_int_to_char`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_int_to_char [`transmute_int_to_float`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_int_to_float +[`transmute_int_to_non_zero`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_int_to_non_zero [`transmute_null_to_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_null_to_fn [`transmute_num_to_bytes`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_num_to_bytes [`transmute_ptr_to_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_ptr_to_ptr diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs index 0dab6b5f3..2577cdc8c 100644 --- a/clippy_lints/src/declared_lints.rs +++ b/clippy_lints/src/declared_lints.rs @@ -577,6 +577,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[ crate::transmute::TRANSMUTE_INT_TO_BOOL_INFO, crate::transmute::TRANSMUTE_INT_TO_CHAR_INFO, crate::transmute::TRANSMUTE_INT_TO_FLOAT_INFO, + crate::transmute::TRANSMUTE_INT_TO_NON_ZERO_INFO, crate::transmute::TRANSMUTE_NULL_TO_FN_INFO, crate::transmute::TRANSMUTE_NUM_TO_BYTES_INFO, crate::transmute::TRANSMUTE_PTR_TO_PTR_INFO, diff --git a/clippy_lints/src/transmute/mod.rs b/clippy_lints/src/transmute/mod.rs index c0d290b5a..c01cbe509 100644 --- a/clippy_lints/src/transmute/mod.rs +++ b/clippy_lints/src/transmute/mod.rs @@ -3,6 +3,7 @@ mod transmute_float_to_int; mod transmute_int_to_bool; mod transmute_int_to_char; mod transmute_int_to_float; +mod transmute_int_to_non_zero; mod transmute_null_to_fn; mod transmute_num_to_bytes; mod transmute_ptr_to_ptr; @@ -253,6 +254,31 @@ declare_clippy_lint! { "transmutes from an integer to a float" } +declare_clippy_lint! { + /// ### What it does + /// Checks for transmutes from integers to `NonZero*` types, and suggests their `new_unchecked` + /// method instead. + /// + /// ### Why is this bad? + /// Transmutes work on any types and thus might cause unsoundness when those types change + /// elsewhere. `new_unchecked` only works for the appropriate types instead. + /// + /// ### Example + /// ```rust + /// # use core::num::NonZeroU32; + /// let _non_zero: NonZeroU32 = unsafe { std::mem::transmute(123) }; + /// ``` + /// Use instead: + /// ```rust + /// # use core::num::NonZeroU32; + /// let _non_zero = unsafe { NonZeroU32::new_unchecked(123) }; + /// ``` + #[clippy::version = "1.69.0"] + pub TRANSMUTE_INT_TO_NON_ZERO, + complexity, + "transmutes from an integer to a non-zero wrapper" +} + declare_clippy_lint! { /// ### What it does /// Checks for transmutes from a float to an integer. @@ -451,6 +477,7 @@ impl_lint_pass!(Transmute => [ TRANSMUTE_BYTES_TO_STR, TRANSMUTE_INT_TO_BOOL, TRANSMUTE_INT_TO_FLOAT, + TRANSMUTE_INT_TO_NON_ZERO, TRANSMUTE_FLOAT_TO_INT, TRANSMUTE_NUM_TO_BYTES, UNSOUND_COLLECTION_TRANSMUTE, @@ -501,6 +528,7 @@ impl<'tcx> LateLintPass<'tcx> for Transmute { | transmute_ptr_to_ptr::check(cx, e, from_ty, to_ty, arg) | transmute_int_to_bool::check(cx, e, from_ty, to_ty, arg) | transmute_int_to_float::check(cx, e, from_ty, to_ty, arg, const_context) + | transmute_int_to_non_zero::check(cx, e, from_ty, to_ty, arg) | transmute_float_to_int::check(cx, e, from_ty, to_ty, arg, const_context) | transmute_num_to_bytes::check(cx, e, from_ty, to_ty, arg, const_context) | ( diff --git a/clippy_lints/src/transmute/transmute_int_to_non_zero.rs b/clippy_lints/src/transmute/transmute_int_to_non_zero.rs new file mode 100644 index 000000000..550365325 --- /dev/null +++ b/clippy_lints/src/transmute/transmute_int_to_non_zero.rs @@ -0,0 +1,61 @@ +use super::TRANSMUTE_INT_TO_NON_ZERO; +use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::sugg; +use rustc_errors::Applicability; +use rustc_hir::Expr; +use rustc_lint::LateContext; +use rustc_middle::{ + query::Key, + ty::{self, Ty}, +}; +use rustc_span::symbol::sym; + +/// Checks for `transmute_int_to_non_zero` lint. +/// Returns `true` if it's triggered, otherwise returns `false`. +pub(super) fn check<'tcx>( + cx: &LateContext<'tcx>, + e: &'tcx Expr<'_>, + from_ty: Ty<'tcx>, + to_ty: Ty<'tcx>, + arg: &'tcx Expr<'_>, +) -> bool { + let (ty::Int(_) | ty::Uint(_), Some(to_ty_id)) = (&from_ty.kind(), to_ty.ty_adt_id()) else { + return false; + }; + let Some(to_type_sym) = cx.tcx.get_diagnostic_name(to_ty_id) else { + return false; + }; + + if !matches!( + to_type_sym, + sym::NonZeroU8 + | sym::NonZeroU16 + | sym::NonZeroU32 + | sym::NonZeroU64 + | sym::NonZeroU128 + | sym::NonZeroI8 + | sym::NonZeroI16 + | sym::NonZeroI32 + | sym::NonZeroI64 + | sym::NonZeroI128 + ) { + return false; + } + + span_lint_and_then( + cx, + TRANSMUTE_INT_TO_NON_ZERO, + e.span, + &format!("transmute from a `{from_ty}` to a `{to_type_sym}`"), + |diag| { + let arg = sugg::Sugg::hir(cx, arg, ".."); + diag.span_suggestion( + e.span, + "consider using", + format!("{to_type_sym}::{}({arg})", sym::new_unchecked), + Applicability::Unspecified, + ); + }, + ); + true +} diff --git a/tests/ui/transmute_int_to_non_zero.rs b/tests/ui/transmute_int_to_non_zero.rs new file mode 100644 index 000000000..a38406782 --- /dev/null +++ b/tests/ui/transmute_int_to_non_zero.rs @@ -0,0 +1,41 @@ +#![warn(clippy::transmute_int_to_non_zero)] + +use core::num::*; + +fn main() { + let int_u8: u8 = 1; + let int_u16: u16 = 1; + let int_u32: u32 = 1; + let int_u64: u64 = 1; + let int_u128: u128 = 1; + + let int_i8: i8 = 1; + let int_i16: i16 = 1; + let int_i32: i32 = 1; + let int_i64: i64 = 1; + let int_i128: i128 = 1; + + let _: NonZeroU8 = unsafe { std::mem::transmute(int_u8) }; + let _: NonZeroU16 = unsafe { std::mem::transmute(int_u16) }; + let _: NonZeroU32 = unsafe { std::mem::transmute(int_u32) }; + let _: NonZeroU64 = unsafe { std::mem::transmute(int_u64) }; + let _: NonZeroU128 = unsafe { std::mem::transmute(int_u128) }; + + let _: NonZeroI8 = unsafe { std::mem::transmute(int_i8) }; + let _: NonZeroI16 = unsafe { std::mem::transmute(int_i16) }; + let _: NonZeroI32 = unsafe { std::mem::transmute(int_i32) }; + let _: NonZeroI64 = unsafe { std::mem::transmute(int_i64) }; + let _: NonZeroI128 = unsafe { std::mem::transmute(int_i128) }; + + let _: NonZeroU8 = unsafe { NonZeroU8::new_unchecked(int_u8) }; + let _: NonZeroU16 = unsafe { NonZeroU16::new_unchecked(int_u16) }; + let _: NonZeroU32 = unsafe { NonZeroU32::new_unchecked(int_u32) }; + let _: NonZeroU64 = unsafe { NonZeroU64::new_unchecked(int_u64) }; + let _: NonZeroU128 = unsafe { NonZeroU128::new_unchecked(int_u128) }; + + let _: NonZeroI8 = unsafe { NonZeroI8::new_unchecked(int_i8) }; + let _: NonZeroI16 = unsafe { NonZeroI16::new_unchecked(int_i16) }; + let _: NonZeroI32 = unsafe { NonZeroI32::new_unchecked(int_i32) }; + let _: NonZeroI64 = unsafe { NonZeroI64::new_unchecked(int_i64) }; + let _: NonZeroI128 = unsafe { NonZeroI128::new_unchecked(int_i128) }; +} diff --git a/tests/ui/transmute_int_to_non_zero.stderr b/tests/ui/transmute_int_to_non_zero.stderr new file mode 100644 index 000000000..33f8ce79e --- /dev/null +++ b/tests/ui/transmute_int_to_non_zero.stderr @@ -0,0 +1,64 @@ +error: transmute from a `u8` to a `NonZeroU8` + --> $DIR/transmute_int_to_non_zero.rs:18:33 + | +LL | let _: NonZeroU8 = unsafe { std::mem::transmute(int_u8) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroU8::new_unchecked(int_u8)` + | + = note: `-D clippy::transmute-int-to-non-zero` implied by `-D warnings` + +error: transmute from a `u16` to a `NonZeroU16` + --> $DIR/transmute_int_to_non_zero.rs:19:34 + | +LL | let _: NonZeroU16 = unsafe { std::mem::transmute(int_u16) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroU16::new_unchecked(int_u16)` + +error: transmute from a `u32` to a `NonZeroU32` + --> $DIR/transmute_int_to_non_zero.rs:20:34 + | +LL | let _: NonZeroU32 = unsafe { std::mem::transmute(int_u32) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroU32::new_unchecked(int_u32)` + +error: transmute from a `u64` to a `NonZeroU64` + --> $DIR/transmute_int_to_non_zero.rs:21:34 + | +LL | let _: NonZeroU64 = unsafe { std::mem::transmute(int_u64) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroU64::new_unchecked(int_u64)` + +error: transmute from a `u128` to a `NonZeroU128` + --> $DIR/transmute_int_to_non_zero.rs:22:35 + | +LL | let _: NonZeroU128 = unsafe { std::mem::transmute(int_u128) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroU128::new_unchecked(int_u128)` + +error: transmute from a `i8` to a `NonZeroI8` + --> $DIR/transmute_int_to_non_zero.rs:24:33 + | +LL | let _: NonZeroI8 = unsafe { std::mem::transmute(int_i8) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroI8::new_unchecked(int_i8)` + +error: transmute from a `i16` to a `NonZeroI16` + --> $DIR/transmute_int_to_non_zero.rs:25:34 + | +LL | let _: NonZeroI16 = unsafe { std::mem::transmute(int_i16) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroI16::new_unchecked(int_i16)` + +error: transmute from a `i32` to a `NonZeroI32` + --> $DIR/transmute_int_to_non_zero.rs:26:34 + | +LL | let _: NonZeroI32 = unsafe { std::mem::transmute(int_i32) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroI32::new_unchecked(int_i32)` + +error: transmute from a `i64` to a `NonZeroI64` + --> $DIR/transmute_int_to_non_zero.rs:27:34 + | +LL | let _: NonZeroI64 = unsafe { std::mem::transmute(int_i64) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroI64::new_unchecked(int_i64)` + +error: transmute from a `i128` to a `NonZeroI128` + --> $DIR/transmute_int_to_non_zero.rs:28:35 + | +LL | let _: NonZeroI128 = unsafe { std::mem::transmute(int_i128) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `NonZeroI128::new_unchecked(int_i128)` + +error: aborting due to 10 previous errors +