From 8528ac6e3595fa0afe47d05513cfb0de73171ebe Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 4 Apr 2023 18:31:25 +0000
Subject: [PATCH] Do not suppress temporary_cstring_as_ptr in macros.
---
compiler/rustc_lint/src/methods.rs | 49 +++----------------
.../ui/lint/lint-temporary-cstring-as-ptr.rs | 8 +++
.../lint/lint-temporary-cstring-as-ptr.stderr | 19 ++++++-
3 files changed, 33 insertions(+), 43 deletions(-)
diff --git a/compiler/rustc_lint/src/methods.rs b/compiler/rustc_lint/src/methods.rs
index 3045fc1a476..4c25d94a1f3 100644
--- a/compiler/rustc_lint/src/methods.rs
+++ b/compiler/rustc_lint/src/methods.rs
@@ -2,9 +2,9 @@ use crate::lints::CStringPtr;
use crate::LateContext;
use crate::LateLintPass;
use crate::LintContext;
-use rustc_hir::{Expr, ExprKind, PathSegment};
+use rustc_hir::{Expr, ExprKind};
use rustc_middle::ty;
-use rustc_span::{symbol::sym, ExpnKind, Span};
+use rustc_span::{symbol::sym, Span};
declare_lint! {
/// The `temporary_cstring_as_ptr` lint detects getting the inner pointer of
@@ -34,47 +34,14 @@ declare_lint! {
declare_lint_pass!(TemporaryCStringAsPtr => [TEMPORARY_CSTRING_AS_PTR]);
-fn in_macro(span: Span) -> bool {
- if span.from_expansion() {
- !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
- } else {
- false
- }
-}
-
-fn first_method_call<'tcx>(
- expr: &'tcx Expr<'tcx>,
-) -> Option<(&'tcx PathSegment<'tcx>, &'tcx Expr<'tcx>)> {
- if let ExprKind::MethodCall(path, receiver, args, ..) = &expr.kind {
- if args.iter().any(|e| e.span.from_expansion()) || receiver.span.from_expansion() {
- None
- } else {
- Some((path, *receiver))
- }
- } else {
- None
- }
-}
-
impl<'tcx> LateLintPass<'tcx> for TemporaryCStringAsPtr {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- if in_macro(expr.span) {
- return;
- }
-
- match first_method_call(expr) {
- Some((path, unwrap_arg)) if path.ident.name == sym::as_ptr => {
- let as_ptr_span = path.ident.span;
- match first_method_call(unwrap_arg) {
- Some((path, receiver))
- if path.ident.name == sym::unwrap || path.ident.name == sym::expect =>
- {
- lint_cstring_as_ptr(cx, as_ptr_span, receiver, unwrap_arg);
- }
- _ => return,
- }
- }
- _ => return,
+ if let ExprKind::MethodCall(as_ptr_path, as_ptr_receiver, ..) = expr.kind
+ && as_ptr_path.ident.name == sym::as_ptr
+ && let ExprKind::MethodCall(unwrap_path, unwrap_receiver, ..) = as_ptr_receiver.kind
+ && (unwrap_path.ident.name == sym::unwrap || unwrap_path.ident.name == sym::expect)
+ {
+ lint_cstring_as_ptr(cx, as_ptr_path.ident.span, unwrap_receiver, as_ptr_receiver);
}
}
}
diff --git a/tests/ui/lint/lint-temporary-cstring-as-ptr.rs b/tests/ui/lint/lint-temporary-cstring-as-ptr.rs
index 7aa4f2e1e00..fab792f1284 100644
--- a/tests/ui/lint/lint-temporary-cstring-as-ptr.rs
+++ b/tests/ui/lint/lint-temporary-cstring-as-ptr.rs
@@ -3,7 +3,15 @@
use std::ffi::CString;
+macro_rules! mymacro {
+ () => {
+ let s = CString::new("some text").unwrap().as_ptr();
+ //~^ ERROR getting the inner pointer of a temporary `CString`
+ }
+}
+
fn main() {
let s = CString::new("some text").unwrap().as_ptr();
//~^ ERROR getting the inner pointer of a temporary `CString`
+ mymacro!();
}
diff --git a/tests/ui/lint/lint-temporary-cstring-as-ptr.stderr b/tests/ui/lint/lint-temporary-cstring-as-ptr.stderr
index 79ef57dd1a3..4e5c8aa0693 100644
--- a/tests/ui/lint/lint-temporary-cstring-as-ptr.stderr
+++ b/tests/ui/lint/lint-temporary-cstring-as-ptr.stderr
@@ -1,5 +1,5 @@
error: getting the inner pointer of a temporary `CString`
- --> $DIR/lint-temporary-cstring-as-ptr.rs:7:48
+ --> $DIR/lint-temporary-cstring-as-ptr.rs:14:48
|
LL | let s = CString::new("some text").unwrap().as_ptr();
| ---------------------------------- ^^^^^^ this pointer will be invalid
@@ -14,5 +14,20 @@ note: the lint level is defined here
LL | #![deny(temporary_cstring_as_ptr)]
| ^^^^^^^^^^^^^^^^^^^^^^^^
-error: aborting due to previous error
+error: getting the inner pointer of a temporary `CString`
+ --> $DIR/lint-temporary-cstring-as-ptr.rs:8:52
+ |
+LL | let s = CString::new("some text").unwrap().as_ptr();
+ | ---------------------------------- ^^^^^^ this pointer will be invalid
+ | |
+ | this `CString` is deallocated at the end of the statement, bind it to a variable to extend its lifetime
+...
+LL | mymacro!();
+ | ---------- in this macro invocation
+ |
+ = note: pointers do not have a lifetime; when calling `as_ptr` the `CString` will be deallocated at the end of the statement because nothing is referencing it as far as the type system is concerned
+ = help: for more information, see https://doc.rust-lang.org/reference/destructors.html
+ = note: this error originates in the macro `mymacro` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors