diff --git a/compiler/rustc_lint/src/reference_casting.rs b/compiler/rustc_lint/src/reference_casting.rs index 4c40abc8ad890..cba4731554811 100644 --- a/compiler/rustc_lint/src/reference_casting.rs +++ b/compiler/rustc_lint/src/reference_casting.rs @@ -37,59 +37,73 @@ declare_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]); impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) { - let Some((is_assignment, e)) = is_operation_we_care_about(cx, expr) else { - return; - }; - - let init = cx.expr_or_init(e); - - let Some(ty_has_interior_mutability) = is_cast_from_const_to_mut(cx, init) else { - return; - }; - let orig_cast = if init.span != e.span { Some(init.span) } else { None }; - let ty_has_interior_mutability = ty_has_interior_mutability.then_some(()); - - cx.emit_spanned_lint( - INVALID_REFERENCE_CASTING, - expr.span, - if is_assignment { - InvalidReferenceCastingDiag::AssignToRef { orig_cast, ty_has_interior_mutability } - } else { - InvalidReferenceCastingDiag::BorrowAsMut { orig_cast, ty_has_interior_mutability } - }, - ); + if let Some((e, pat)) = borrow_or_assign(cx, expr) { + if matches!(pat, PatternKind::Borrow { mutbl: Mutability::Mut } | PatternKind::Assign) { + let init = cx.expr_or_init(e); + + let Some(ty_has_interior_mutability) = is_cast_from_ref_to_mut_ptr(cx, init) else { + return; + }; + let orig_cast = if init.span != e.span { Some(init.span) } else { None }; + let ty_has_interior_mutability = ty_has_interior_mutability.then_some(()); + + cx.emit_spanned_lint( + INVALID_REFERENCE_CASTING, + expr.span, + if pat == PatternKind::Assign { + InvalidReferenceCastingDiag::AssignToRef { + orig_cast, + ty_has_interior_mutability, + } + } else { + InvalidReferenceCastingDiag::BorrowAsMut { + orig_cast, + ty_has_interior_mutability, + } + }, + ); + } + } } } -fn is_operation_we_care_about<'tcx>( +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +enum PatternKind { + Borrow { mutbl: Mutability }, + Assign, +} + +fn borrow_or_assign<'tcx>( cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>, -) -> Option<(bool, &'tcx Expr<'tcx>)> { - fn deref_assign_or_addr_of<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<(bool, &'tcx Expr<'tcx>)> { - // &mut - let inner = if let ExprKind::AddrOf(_, Mutability::Mut, expr) = expr.kind { - expr +) -> Option<(&'tcx Expr<'tcx>, PatternKind)> { + fn deref_assign_or_addr_of<'tcx>( + expr: &'tcx Expr<'tcx>, + ) -> Option<(&'tcx Expr<'tcx>, PatternKind)> { + // &(mut) + let (inner, pat) = if let ExprKind::AddrOf(_, mutbl, expr) = expr.kind { + (expr, PatternKind::Borrow { mutbl }) // = ... } else if let ExprKind::Assign(expr, _, _) = expr.kind { - expr + (expr, PatternKind::Assign) // += ... } else if let ExprKind::AssignOp(_, expr, _) = expr.kind { - expr + (expr, PatternKind::Assign) } else { return None; }; - if let ExprKind::Unary(UnOp::Deref, e) = &inner.kind { - Some((!matches!(expr.kind, ExprKind::AddrOf(..)), e)) - } else { - None - } + // * + let ExprKind::Unary(UnOp::Deref, e) = &inner.kind else { + return None; + }; + Some((e, pat)) } fn ptr_write<'tcx>( cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>, - ) -> Option<(bool, &'tcx Expr<'tcx>)> { + ) -> Option<(&'tcx Expr<'tcx>, PatternKind)> { if let ExprKind::Call(path, [arg_ptr, _arg_val]) = e.kind && let ExprKind::Path(ref qpath) = path.kind && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() @@ -98,7 +112,7 @@ fn is_operation_we_care_about<'tcx>( Some(sym::ptr_write | sym::ptr_write_volatile | sym::ptr_write_unaligned) ) { - Some((true, arg_ptr)) + Some((arg_ptr, PatternKind::Assign)) } else { None } @@ -107,7 +121,7 @@ fn is_operation_we_care_about<'tcx>( deref_assign_or_addr_of(e).or_else(|| ptr_write(cx, e)) } -fn is_cast_from_const_to_mut<'tcx>( +fn is_cast_from_ref_to_mut_ptr<'tcx>( cx: &LateContext<'tcx>, orig_expr: &'tcx Expr<'tcx>, ) -> Option { @@ -122,12 +136,12 @@ fn is_cast_from_const_to_mut<'tcx>( let start_ty = cx.typeck_results().node_type(e.hir_id); if let ty::Ref(_, inner_ty, Mutability::Not) = start_ty.kind() { - // If an UnsafeCell method is involved we need to additionally check the + // If an UnsafeCell method is involved, we need to additionally check the // inner type for the presence of the Freeze trait (ie does NOT contain // an UnsafeCell), since in that case we would incorrectly lint on valid casts. // - // We also consider non concrete skeleton types (ie generics) - // to be an issue since there is no way to make it safe for abitrary types. + // Except on the presence of non concrete skeleton types (ie generics) + // since there is no way to make it safe for arbitrary types. let inner_ty_has_interior_mutability = !inner_ty.is_freeze(cx.tcx, cx.param_env) && inner_ty.has_concrete_skeleton(); (!need_check_freeze || !inner_ty_has_interior_mutability)