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Extract casting detection logic in it's own function

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This commit is contained in:
Urgau 2023-12-12 19:25:34 +01:00
parent 1aa6aefdc9
commit 07e6224eff
1 changed files with 24 additions and 19 deletions
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43
compiler/rustc_lint/src/reference_casting.rs
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@ -111,9 +111,6 @@ fn is_cast_from_const_to_mut<'tcx>(
cx: &LateContext<'tcx>,
orig_expr: &'tcx Expr<'tcx>,
) -> Option<bool> {
let mut need_check_freeze = false;
let mut e = orig_expr;
let end_ty = cx.typeck_results().node_type(orig_expr.hir_id);
// Bail out early if the end type is **not** a mutable pointer.
@ -121,6 +118,28 @@ fn is_cast_from_const_to_mut<'tcx>(
return None;
}
let (e, need_check_freeze) = peel_casts(cx, orig_expr);
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
// 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.
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)
.then_some(inner_ty_has_interior_mutability)
} else {
None
}
}
fn peel_casts<'tcx>(cx: &LateContext<'tcx>, mut e: &'tcx Expr<'tcx>) -> (&'tcx Expr<'tcx>, bool) {
let mut gone_trough_unsafe_cell_raw_get = false;
loop {
e = e.peel_blocks();
// <expr> as ...
@ -145,7 +164,7 @@ fn is_cast_from_const_to_mut<'tcx>(
)
{
if cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id) {
need_check_freeze = true;
gone_trough_unsafe_cell_raw_get = true;
}
arg
} else {
@ -153,19 +172,5 @@ 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
// 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.
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)
.then_some(inner_ty_has_interior_mutability)
} else {
None
}
(e, gone_trough_unsafe_cell_raw_get)
}