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use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::is_diag_trait_item;
use clippy_utils::source::snippet_with_context;
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, print::with_forced_trimmed_paths};
use rustc_span::sym;
use super::SUSPICIOUS_TO_OWNED;
pub fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>) -> bool {
if_chain! {
if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
if is_diag_trait_item(cx, method_def_id, sym::ToOwned);
let input_type = cx.typeck_results().expr_ty(expr);
if let ty::Adt(adt, _) = cx.typeck_results().expr_ty(expr).kind();
if cx.tcx.is_diagnostic_item(sym::Cow, adt.did());
then {
let mut app = Applicability::MaybeIncorrect;
let recv_snip = snippet_with_context(cx, recv.span, expr.span.ctxt(), "..", &mut app).0;
span_lint_and_then(
cx,
SUSPICIOUS_TO_OWNED,
expr.span,
&with_forced_trimmed_paths!(format!(
"this `to_owned` call clones the {input_type} itself and does not cause the {input_type} contents to become owned"
)),
|diag| {
diag.span_suggestion(
expr.span,
"depending on intent, either make the Cow an Owned variant",
format!("{recv_snip}.into_owned()"),
app
);
diag.span_suggestion(
expr.span,
"or clone the Cow itself",
format!("{recv_snip}.clone()"),
app
);
}
);
return true;
}
}
false
}
|
