diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs index b21f81bd517..75042d846d8 100644 --- a/clippy_lints/src/types.rs +++ b/clippy_lints/src/types.rs @@ -8,7 +8,6 @@ use if_chain::if_chain; use rustc_ast::{FloatTy, IntTy, LitFloatType, LitIntType, LitKind, UintTy}; use rustc_errors::{Applicability, DiagnosticBuilder}; use rustc_hir as hir; -use rustc_hir::def::Res; use rustc_hir::intravisit::{walk_body, walk_expr, walk_ty, FnKind, NestedVisitorMap, Visitor}; use rustc_hir::{ BinOpKind, Block, Body, Expr, ExprKind, FnDecl, FnRetTy, FnSig, GenericArg, GenericBounds, GenericParamKind, HirId, @@ -33,9 +32,9 @@ use crate::consts::{constant, Constant}; use crate::utils::paths; use crate::utils::sugg::Sugg; use crate::utils::{ - clip, comparisons, differing_macro_contexts, higher, in_constant, indent_of, int_bits, is_type_diagnostic_item, - last_path_segment, match_def_path, match_path, meets_msrv, method_chain_args, multispan_sugg, - numeric_literal::NumericLiteral, qpath_res, reindent_multiline, sext, snippet, snippet_opt, + clip, comparisons, differing_macro_contexts, higher, in_constant, indent_of, int_bits, is_hir_ty_cfg_dependant, + is_type_diagnostic_item, last_path_segment, match_def_path, match_path, meets_msrv, method_chain_args, + multispan_sugg, numeric_literal::NumericLiteral, qpath_res, reindent_multiline, sext, snippet, snippet_opt, snippet_with_applicability, snippet_with_macro_callsite, span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then, unsext, }; @@ -1282,8 +1281,8 @@ declare_clippy_lint! { } declare_clippy_lint! { - /// **What it does:** Checks for casts from a less-strictly-aligned pointer to a - /// more-strictly-aligned pointer + /// **What it does:** Checks for casts, using `as` or `pointer::cast`, + /// from a less-strictly-aligned pointer to a more-strictly-aligned pointer /// /// **Why is this bad?** Dereferencing the resulting pointer may be undefined /// behavior. @@ -1296,6 +1295,9 @@ declare_clippy_lint! { /// ```rust /// let _ = (&1u8 as *const u8) as *const u16; /// let _ = (&mut 1u8 as *mut u8) as *mut u16; + /// + /// (&1u8 as *const u8).cast::(); + /// (&mut 1u8 as *mut u8).cast::(); /// ``` pub CAST_PTR_ALIGNMENT, pedantic, @@ -1637,12 +1639,8 @@ impl<'tcx> LateLintPass<'tcx> for Casts { return; } if let ExprKind::Cast(ref ex, cast_to) = expr.kind { - if let TyKind::Path(QPath::Resolved(_, path)) = cast_to.kind { - if let Res::Def(_, def_id) = path.res { - if cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr) { - return; - } - } + if is_hir_ty_cfg_dependant(cx, cast_to) { + return; } let (cast_from, cast_to) = (cx.typeck_results().expr_ty(ex), cx.typeck_results().expr_ty(expr)); lint_fn_to_numeric_cast(cx, expr, ex, cast_from, cast_to); @@ -1692,6 +1690,19 @@ impl<'tcx> LateLintPass<'tcx> for Casts { } lint_cast_ptr_alignment(cx, expr, cast_from, cast_to); + } else if let ExprKind::MethodCall(method_path, _, args, _) = expr.kind { + if_chain! { + if method_path.ident.name == sym!(cast); + if let Some(generic_args) = method_path.args; + if let [GenericArg::Type(cast_to)] = generic_args.args; + // There probably is no obvious reason to do this, just to be consistent with `as` cases. + if !is_hir_ty_cfg_dependant(cx, cast_to); + then { + let (cast_from, cast_to) = + (cx.typeck_results().expr_ty(&args[0]), cx.typeck_results().expr_ty(expr)); + lint_cast_ptr_alignment(cx, expr, cast_from, cast_to); + } + } } } } diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs index 8f54cad7728..27f4cb2b254 100644 --- a/clippy_lints/src/utils/mod.rs +++ b/clippy_lints/src/utils/mod.rs @@ -1686,6 +1686,18 @@ macro_rules! unwrap_cargo_metadata { }}; } +pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool { + if_chain! { + if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind; + if let Res::Def(_, def_id) = path.res; + then { + cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr) + } else { + false + } + } +} + #[cfg(test)] mod test { use super::{reindent_multiline, without_block_comments}; diff --git a/tests/ui/cast_alignment.rs b/tests/ui/cast_alignment.rs index 4c08935639f..d011e84b115 100644 --- a/tests/ui/cast_alignment.rs +++ b/tests/ui/cast_alignment.rs @@ -12,6 +12,10 @@ fn main() { (&1u8 as *const u8) as *const u16; (&mut 1u8 as *mut u8) as *mut u16; + // cast to more-strictly-aligned type, but with the `pointer::cast` function. + (&1u8 as *const u8).cast::(); + (&mut 1u8 as *mut u8).cast::(); + /* These should be ok */ // not a pointer type diff --git a/tests/ui/cast_alignment.stderr b/tests/ui/cast_alignment.stderr index 79219f86155..7998b787b91 100644 --- a/tests/ui/cast_alignment.stderr +++ b/tests/ui/cast_alignment.stderr @@ -12,5 +12,17 @@ error: casting from `*mut u8` to a more-strictly-aligned pointer (`*mut u16`) (1 LL | (&mut 1u8 as *mut u8) as *mut u16; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -error: aborting due to 2 previous errors +error: casting from `*const u8` to a more-strictly-aligned pointer (`*const u16`) (1 < 2 bytes) + --> $DIR/cast_alignment.rs:16:5 + | +LL | (&1u8 as *const u8).cast::(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: casting from `*mut u8` to a more-strictly-aligned pointer (`*mut u16`) (1 < 2 bytes) + --> $DIR/cast_alignment.rs:17:5 + | +LL | (&mut 1u8 as *mut u8).cast::(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 4 previous errors