From ecc201253ee060071442f6f0c1a52b380aa3b3af Mon Sep 17 00:00:00 2001 From: Alex Macleod Date: Thu, 23 Mar 2023 18:58:10 +0000 Subject: [PATCH] Wrap transmutes_expressible_as_ptr_casts suggestions in parentheses --- .../transmute/transmutes_expressible_as_ptr_casts.rs | 11 +++++++++-- tests/ui/transmutes_expressible_as_ptr_casts.fixed | 8 +++++++- tests/ui/transmutes_expressible_as_ptr_casts.rs | 8 +++++++- tests/ui/transmutes_expressible_as_ptr_casts.stderr | 8 +++++++- 4 files changed, 30 insertions(+), 5 deletions(-) diff --git a/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs b/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs index 8530b43243f..85cd74f23ef 100644 --- a/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs +++ b/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs @@ -2,8 +2,9 @@ use super::utils::check_cast; use super::TRANSMUTES_EXPRESSIBLE_AS_PTR_CASTS; use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::sugg::Sugg; +use rustc_ast::ExprPrecedence; use rustc_errors::Applicability; -use rustc_hir::Expr; +use rustc_hir::{Expr, Node}; use rustc_lint::LateContext; use rustc_middle::ty::{cast::CastKind, Ty}; @@ -19,7 +20,7 @@ pub(super) fn check<'tcx>( ) -> bool { use CastKind::{AddrPtrCast, ArrayPtrCast, FnPtrAddrCast, FnPtrPtrCast, PtrAddrCast, PtrPtrCast}; let mut app = Applicability::MachineApplicable; - let sugg = match check_cast(cx, e, from_ty, to_ty) { + let mut sugg = match check_cast(cx, e, from_ty, to_ty) { Some(PtrPtrCast | AddrPtrCast | ArrayPtrCast | FnPtrPtrCast | FnPtrAddrCast) => { Sugg::hir_with_context(cx, arg, e.span.ctxt(), "..", &mut app) .as_ty(to_ty.to_string()) @@ -39,6 +40,12 @@ pub(super) fn check<'tcx>( _ => return false, }; + if let Node::Expr(parent) = cx.tcx.hir().get_parent(e.hir_id) + && parent.precedence().order() > ExprPrecedence::Cast.order() + { + sugg = format!("({sugg})"); + } + span_lint_and_sugg( cx, TRANSMUTES_EXPRESSIBLE_AS_PTR_CASTS, diff --git a/tests/ui/transmutes_expressible_as_ptr_casts.fixed b/tests/ui/transmutes_expressible_as_ptr_casts.fixed index 55307506eb3..cc84ba25bd0 100644 --- a/tests/ui/transmutes_expressible_as_ptr_casts.fixed +++ b/tests/ui/transmutes_expressible_as_ptr_casts.fixed @@ -4,7 +4,7 @@ // would otherwise be responsible for #![warn(clippy::useless_transmute)] #![warn(clippy::transmute_ptr_to_ptr)] -#![allow(dead_code, unused_unsafe, clippy::borrow_as_ptr)] +#![allow(unused, clippy::borrow_as_ptr)] use std::mem::{size_of, transmute}; @@ -77,3 +77,9 @@ fn cannot_be_expressed_as_pointer_cast(in_param: Single) -> Pair { unsafe { transmute::(in_param) } } + +fn issue_10449() { + fn f() {} + + let _x: u8 = unsafe { *(f as *const u8) }; +} diff --git a/tests/ui/transmutes_expressible_as_ptr_casts.rs b/tests/ui/transmutes_expressible_as_ptr_casts.rs index e7360f3f9dc..aa65ab4dd24 100644 --- a/tests/ui/transmutes_expressible_as_ptr_casts.rs +++ b/tests/ui/transmutes_expressible_as_ptr_casts.rs @@ -4,7 +4,7 @@ // would otherwise be responsible for #![warn(clippy::useless_transmute)] #![warn(clippy::transmute_ptr_to_ptr)] -#![allow(dead_code, unused_unsafe, clippy::borrow_as_ptr)] +#![allow(unused, clippy::borrow_as_ptr)] use std::mem::{size_of, transmute}; @@ -77,3 +77,9 @@ fn cannot_be_expressed_as_pointer_cast(in_param: Single) -> Pair { unsafe { transmute::(in_param) } } + +fn issue_10449() { + fn f() {} + + let _x: u8 = unsafe { *std::mem::transmute::(f) }; +} diff --git a/tests/ui/transmutes_expressible_as_ptr_casts.stderr b/tests/ui/transmutes_expressible_as_ptr_casts.stderr index e862fcb67a4..58f5162c78e 100644 --- a/tests/ui/transmutes_expressible_as_ptr_casts.stderr +++ b/tests/ui/transmutes_expressible_as_ptr_casts.stderr @@ -58,5 +58,11 @@ error: transmute from a reference to a pointer LL | unsafe { transmute::<&[i32; 1], *const u8>(in_param) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `in_param as *const [i32; 1] as *const u8` -error: aborting due to 9 previous errors +error: transmute from `fn()` to `*const u8` which could be expressed as a pointer cast instead + --> $DIR/transmutes_expressible_as_ptr_casts.rs:84:28 + | +LL | let _x: u8 = unsafe { *std::mem::transmute::(f) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(f as *const u8)` + +error: aborting due to 10 previous errors