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use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::{is_diag_item_method, is_diag_trait_item};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::TyS;
use rustc_span::{sym, Span};
use super::IMPLICIT_CLONE;
pub fn check(cx: &LateContext<'_>, method_name: &str, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, span: Span) {
if_chain! {
if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
if match method_name {
"to_os_string" => is_diag_item_method(cx, method_def_id, sym::OsStr),
"to_owned" => is_diag_trait_item(cx, method_def_id, sym::ToOwned),
"to_path_buf" => is_diag_item_method(cx, method_def_id, sym::Path),
"to_vec" => cx.tcx.impl_of_method(method_def_id)
.map(|impl_did| Some(impl_did) == cx.tcx.lang_items().slice_alloc_impl())
== Some(true),
_ => false,
};
let return_type = cx.typeck_results().expr_ty(expr);
let input_type = cx.typeck_results().expr_ty(recv).peel_refs();
if let Some(ty_name) = input_type.ty_adt_def().map(|adt_def| cx.tcx.item_name(adt_def.did));
if TyS::same_type(return_type, input_type);
then {
span_lint_and_sugg(
cx,
IMPLICIT_CLONE,
span,
&format!("implicitly cloning a `{}` by calling `{}` on its dereferenced type", ty_name, method_name),
"consider using",
"clone".to_string(),
Applicability::MachineApplicable
);
}
}
}
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