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Also lint on cast/cast_mut and ptr::from_mut/ptr::from_ref

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This commit is contained in:
Urgau 2023-07-13 14:13:08 +02:00
parent 0b9529cca3
commit 4b3dadbe5a
4 changed files with 122 additions and 37 deletions
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54
compiler/rustc_lint/src/ptr_nulls.rs
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@ -31,25 +31,45 @@ declare_lint! {
declare_lint_pass!(PtrNullChecks => [USELESS_PTR_NULL_CHECKS]);
fn incorrect_check<'a>(cx: &LateContext<'a>, expr: &Expr<'_>) -> Option<PtrNullChecksDiag<'a>> {
let mut expr = expr.peel_blocks();
/// This function detects and returns the original expression from a series of consecutive casts,
/// ie. `(my_fn as *const _ as *mut _).cast_mut()` would return the expression for `my_fn`.
fn ptr_cast_chain<'a>(cx: &'a LateContext<'_>, mut e: &'a Expr<'a>) -> Option<&'a Expr<'a>> {
let mut had_at_least_one_cast = false;
while let ExprKind::Cast(cast_expr, cast_ty) = expr.kind
&& let TyKind::Ptr(_) = cast_ty.kind {
expr = cast_expr.peel_blocks();
had_at_least_one_cast = true;
}
if !had_at_least_one_cast {
None
} else {
let orig_ty = cx.typeck_results().expr_ty(expr);
if orig_ty.is_fn() {
Some(PtrNullChecksDiag::FnPtr)
} else if orig_ty.is_ref() {
Some(PtrNullChecksDiag::Ref { orig_ty, label: expr.span })
loop {
e = e.peel_blocks();
e = if let ExprKind::Cast(expr, t) = e.kind
&& let TyKind::Ptr(_) = t.kind {
had_at_least_one_cast = true;
expr
} else if let ExprKind::MethodCall(_, expr, [], _) = e.kind
&& let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
&& matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::ptr_cast | sym::ptr_cast_mut)) {
had_at_least_one_cast = true;
expr
} else if let ExprKind::Call(path, [arg]) = e.kind
&& let ExprKind::Path(ref qpath) = path.kind
&& let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
&& matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::ptr_from_ref | sym::ptr_from_mut)) {
had_at_least_one_cast = true;
arg
} else if had_at_least_one_cast {
return Some(e);
} else {
None
}
return None;
};
}
}
fn incorrect_check<'a>(cx: &LateContext<'a>, expr: &Expr<'_>) -> Option<PtrNullChecksDiag<'a>> {
let expr = ptr_cast_chain(cx, expr)?;
let orig_ty = cx.typeck_results().expr_ty(expr);
if orig_ty.is_fn() {
Some(PtrNullChecksDiag::FnPtr)
} else if orig_ty.is_ref() {
Some(PtrNullChecksDiag::Ref { orig_ty, label: expr.span })
} else {
None
}
}