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Clarify invalid_reference_casting lint around interior mutable types

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This commit is contained in:
Urgau 2023-10-04 16:03:39 +02:00
parent dd513e1150
commit e46236cceb
5 changed files with 68 additions and 32 deletions
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26
compiler/rustc_lint/src/reference_casting.rs
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@ -43,19 +43,19 @@ impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting {
let init = cx.expr_or_init(e);
let orig_cast = if is_cast_from_const_to_mut(cx, init) {
if init.span != e.span { Some(init.span) } else { None }
} else {
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 }
InvalidReferenceCastingDiag::AssignToRef { orig_cast, ty_has_interior_mutability }
} else {
InvalidReferenceCastingDiag::BorrowAsMut { orig_cast }
InvalidReferenceCastingDiag::BorrowAsMut { orig_cast, ty_has_interior_mutability }
},
);
}
@ -104,7 +104,10 @@ 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>(cx: &LateContext<'tcx>, orig_expr: &'tcx Expr<'tcx>) -> bool {
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;
@ -112,7 +115,7 @@ fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, orig_expr: &'tcx Expr
// Bail out early if the end type is **not** a mutable pointer.
if !matches!(end_ty.kind(), ty::RawPtr(TypeAndMut { ty: _, mutbl: Mutability::Mut })) {
return false;
return None;
}
loop {
@ -155,10 +158,11 @@ fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, orig_expr: &'tcx Expr
//
// 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.
!need_check_freeze
|| inner_ty.is_freeze(cx.tcx, cx.param_env)
|| !inner_ty.has_concrete_skeleton()
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 {
false
None
}
}