use clippy_utils::diagnostics::span_lint_and_help;

use clippy_utils::ty::is_type_diagnostic_item;

use clippy_utils::{path_res, peel_blocks};

use rustc_hir::def::Res;

use rustc_hir::def_id::LocalDefId;

use rustc_hir::intravisit::FnKind;

use rustc_hir::{Body, ExprKind, FnDecl, FnRetTy};

use rustc_lint::{LateContext, LateLintPass};

use rustc_session::declare_lint_pass;

use rustc_span::{Span, sym};

declare_clippy_lint! {

/// ### What it does

/// Checks for functions with method calls to `.map(_)` on an arg

/// of type `Option` as the outermost expression.

///

/// ### Why is this bad?

/// Taking and returning an `Option<T>` may require additional

/// `Some(_)` and `unwrap` if all you have is a `T`.

///

/// ### Example

/// ```no_run

/// fn double(param: Option<u32>) -> Option<u32> {

/// param.map(|x| x * 2)

/// }

/// ```

/// Use instead:

/// ```no_run

/// fn double(param: u32) -> u32 {

/// param * 2

/// }

/// ```

#[clippy::version = "1.86.0"]

pub SINGLE_OPTION_MAP,

nursery,

"Checks for functions with method calls to `.map(_)` on an arg of type `Option` as the outermost expression."

}

declare_lint_pass!(SingleOptionMap => [SINGLE_OPTION_MAP]);

impl<'tcx> LateLintPass<'tcx> for SingleOptionMap {

}