diff options
| -rw-r--r-- | clippy_lints/src/casts/cast_possible_wrap.rs | 44 | ||||
| -rw-r--r-- | clippy_lints/src/casts/mod.rs | 56 |
2 files changed, 48 insertions, 52 deletions
diff --git a/clippy_lints/src/casts/cast_possible_wrap.rs b/clippy_lints/src/casts/cast_possible_wrap.rs new file mode 100644 index 00000000000..56d301ed3e1 --- /dev/null +++ b/clippy_lints/src/casts/cast_possible_wrap.rs @@ -0,0 +1,44 @@ +use rustc_hir::Expr; +use rustc_lint::LateContext; +use rustc_middle::ty::Ty; + +use crate::utils::{is_isize_or_usize, span_lint}; + +use super::{utils, CAST_POSSIBLE_WRAP}; + +pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) { + if !(cast_from.is_integral() && cast_to.is_integral()) { + return; + } + + let arch_64_suffix = " on targets with 64-bit wide pointers"; + let arch_32_suffix = " on targets with 32-bit wide pointers"; + let cast_unsigned_to_signed = !cast_from.is_signed() && cast_to.is_signed(); + let from_nbits = utils::int_ty_to_nbits(cast_from, cx.tcx); + let to_nbits = utils::int_ty_to_nbits(cast_to, cx.tcx); + + let (should_lint, suffix) = match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) { + (true, true) | (false, false) => (to_nbits == from_nbits && cast_unsigned_to_signed, ""), + (true, false) => (to_nbits <= 32 && cast_unsigned_to_signed, arch_32_suffix), + (false, true) => ( + cast_unsigned_to_signed, + if from_nbits == 64 { + arch_64_suffix + } else { + arch_32_suffix + }, + ), + }; + + if should_lint { + span_lint( + cx, + CAST_POSSIBLE_WRAP, + expr.span, + &format!( + "casting `{}` to `{}` may wrap around the value{}", + cast_from, cast_to, suffix, + ), + ); + } +} diff --git a/clippy_lints/src/casts/mod.rs b/clippy_lints/src/casts/mod.rs index f390dfdfab7..01528a5a16a 100644 --- a/clippy_lints/src/casts/mod.rs +++ b/clippy_lints/src/casts/mod.rs @@ -1,5 +1,6 @@ mod cast_lossless; mod cast_possible_truncation; +mod cast_possible_wrap; mod cast_precision_loss; mod cast_sign_loss; mod utils; @@ -20,8 +21,8 @@ use rustc_target::abi::LayoutOf; use crate::utils::sugg::Sugg; use crate::utils::{ - is_hir_ty_cfg_dependant, is_isize_or_usize, meets_msrv, numeric_literal::NumericLiteral, snippet_opt, - snippet_with_applicability, span_lint, span_lint_and_sugg, span_lint_and_then, + is_hir_ty_cfg_dependant, meets_msrv, numeric_literal::NumericLiteral, snippet_opt, snippet_with_applicability, + span_lint, span_lint_and_sugg, span_lint_and_then, }; use utils::int_ty_to_nbits; @@ -255,49 +256,6 @@ declare_clippy_lint! { "casting a function pointer to a numeric type not wide enough to store the address" } -enum ArchSuffix { - _32, - _64, - None, -} - -fn check_truncation_and_wrapping(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) { - let arch_64_suffix = " on targets with 64-bit wide pointers"; - let arch_32_suffix = " on targets with 32-bit wide pointers"; - let cast_unsigned_to_signed = !cast_from.is_signed() && cast_to.is_signed(); - let from_nbits = int_ty_to_nbits(cast_from, cx.tcx); - let to_nbits = int_ty_to_nbits(cast_to, cx.tcx); - let (span_wrap, suffix_wrap) = match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) { - (true, true) | (false, false) => (to_nbits == from_nbits && cast_unsigned_to_signed, ArchSuffix::None), - (true, false) => (to_nbits <= 32 && cast_unsigned_to_signed, ArchSuffix::_32), - (false, true) => ( - cast_unsigned_to_signed, - if from_nbits == 64 { - ArchSuffix::_64 - } else { - ArchSuffix::_32 - }, - ), - }; - if span_wrap { - span_lint( - cx, - CAST_POSSIBLE_WRAP, - expr.span, - &format!( - "casting `{}` to `{}` may wrap around the value{}", - cast_from, - cast_to, - match suffix_wrap { - ArchSuffix::_32 => arch_32_suffix, - ArchSuffix::_64 => arch_64_suffix, - ArchSuffix::None => "", - } - ), - ); - } -} - declare_lint_pass!(Casts => [ CAST_PRECISION_LOSS, CAST_SIGN_LOSS, @@ -449,16 +407,10 @@ fn lint_numeric_casts<'tcx>( cast_to: Ty<'tcx>, ) { cast_possible_truncation::check(cx, expr, cast_from, cast_to); + cast_possible_wrap::check(cx, expr, cast_from, cast_to); cast_precision_loss::check(cx, expr, cast_from, cast_to); cast_lossless::check(cx, expr, cast_op, cast_from, cast_to); cast_sign_loss::check(cx, expr, cast_op, cast_from, cast_to); - - match (cast_from.is_integral(), cast_to.is_integral()) { - (true, true) => { - check_truncation_and_wrapping(cx, expr, cast_from, cast_to); - }, - (_, _) => {}, - } } fn lint_cast_ptr_alignment<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, cast_from: Ty<'tcx>, cast_to: Ty<'tcx>) { |