src/tools/clippy/clippy_lints/src/methods/option_as_ref_cloned.rs

use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::ty::is_type_diagnostic_item;
use rustc_errors::Applicability;
use rustc_hir::Expr;
use rustc_lint::LateContext;
use rustc_span::{sym, Span};

use super::{method_call, OPTION_AS_REF_CLONED};

pub(super) fn check(cx: &LateContext<'_>, cloned_recv: &Expr<'_>, cloned_ident_span: Span) {
    if let Some((method @ ("as_ref" | "as_mut"), as_ref_recv, [], as_ref_ident_span, _)) = method_call(cloned_recv)
        && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(as_ref_recv).peel_refs(), sym::Option)
    {
        span_lint_and_sugg(
            cx,
            OPTION_AS_REF_CLONED,
            as_ref_ident_span.to(cloned_ident_span),
            &format!("cloning an `Option<_>` using `.{method}().cloned()`"),
            "this can be written more concisely by cloning the `Option<_>` directly",
            "clone".into(),
            Applicability::MachineApplicable,
        );
    }
}