diff options
| -rw-r--r-- | clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs | 39 | ||||
| -rw-r--r-- | clippy_lints/src/casts/mod.rs | 40 |
2 files changed, 41 insertions, 38 deletions
diff --git a/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs b/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs new file mode 100644 index 00000000000..0085c7b27b2 --- /dev/null +++ b/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs @@ -0,0 +1,39 @@ +use rustc_errors::Applicability; +use rustc_hir::Expr; +use rustc_lint::LateContext; +use rustc_middle::ty::{self, Ty}; + +use crate::utils::{snippet_with_applicability, span_lint_and_sugg}; + +use super::{utils, FN_TO_NUMERIC_CAST_WITH_TRUNCATION}; + +pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) { + // We only want to check casts to `ty::Uint` or `ty::Int` + match cast_to.kind() { + ty::Uint(_) | ty::Int(..) => { /* continue on */ }, + _ => return, + } + match cast_from.kind() { + ty::FnDef(..) | ty::FnPtr(_) => { + let mut applicability = Applicability::MaybeIncorrect; + let from_snippet = snippet_with_applicability(cx, cast_expr.span, "x", &mut applicability); + + let to_nbits = utils::int_ty_to_nbits(cast_to, cx.tcx); + if to_nbits < cx.tcx.data_layout.pointer_size.bits() { + span_lint_and_sugg( + cx, + FN_TO_NUMERIC_CAST_WITH_TRUNCATION, + expr.span, + &format!( + "casting function pointer `{}` to `{}`, which truncates the value", + from_snippet, cast_to + ), + "try", + format!("{} as usize", from_snippet), + applicability, + ); + } + }, + _ => {}, + } +} diff --git a/clippy_lints/src/casts/mod.rs b/clippy_lints/src/casts/mod.rs index bbe492be72e..a80de01cfaf 100644 --- a/clippy_lints/src/casts/mod.rs +++ b/clippy_lints/src/casts/mod.rs @@ -4,6 +4,7 @@ mod cast_possible_wrap; mod cast_precision_loss; mod cast_sign_loss; mod fn_to_numeric_cast; +mod fn_to_numeric_cast_with_truncation; mod unnecessary_cast; mod utils; @@ -304,7 +305,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts { } fn_to_numeric_cast::check(cx, expr, cast_expr, cast_from, cast_to); - lint_fn_to_numeric_cast(cx, expr, cast_expr, cast_from, cast_to); + fn_to_numeric_cast_with_truncation::check(cx, expr, cast_expr, cast_from, cast_to); lint_cast_ptr_alignment(cx, expr, cast_from, cast_to); if cast_from.is_numeric() && cast_to.is_numeric() && !in_external_macro(cx.sess(), expr.span) { cast_possible_truncation::check(cx, expr, cast_from, cast_to); @@ -358,43 +359,6 @@ fn lint_cast_ptr_alignment<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, cast_f } } -fn lint_fn_to_numeric_cast( - cx: &LateContext<'_>, - expr: &Expr<'_>, - cast_expr: &Expr<'_>, - cast_from: Ty<'_>, - cast_to: Ty<'_>, -) { - // We only want to check casts to `ty::Uint` or `ty::Int` - match cast_to.kind() { - ty::Uint(_) | ty::Int(..) => { /* continue on */ }, - _ => return, - } - match cast_from.kind() { - ty::FnDef(..) | ty::FnPtr(_) => { - let mut applicability = Applicability::MaybeIncorrect; - let from_snippet = snippet_with_applicability(cx, cast_expr.span, "x", &mut applicability); - - let to_nbits = int_ty_to_nbits(cast_to, cx.tcx); - if to_nbits < cx.tcx.data_layout.pointer_size.bits() { - span_lint_and_sugg( - cx, - FN_TO_NUMERIC_CAST_WITH_TRUNCATION, - expr.span, - &format!( - "casting function pointer `{}` to `{}`, which truncates the value", - from_snippet, cast_to - ), - "try", - format!("{} as usize", from_snippet), - applicability, - ); - } - }, - _ => {}, - } -} - declare_clippy_lint! { /// **What it does:** Checks for casts of `&T` to `&mut T` anywhere in the code. /// |