diff options
Diffstat (limited to '')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs b/src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs new file mode 100644 index 000000000..ffd2f4a38 --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs @@ -0,0 +1,64 @@ +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::source::{indent_of, reindent_multiline, snippet_opt}; +use clippy_utils::ty::is_type_diagnostic_item; +use clippy_utils::{is_lang_ctor, path_to_local_id}; +use if_chain::if_chain; +use rustc_errors::Applicability; +use rustc_hir::LangItem::{ResultErr, ResultOk}; +use rustc_hir::{Closure, Expr, ExprKind, PatKind}; +use rustc_lint::LateContext; +use rustc_span::symbol::sym; + +use super::MANUAL_OK_OR; + +pub(super) fn check<'tcx>( + cx: &LateContext<'tcx>, + expr: &'tcx Expr<'tcx>, + recv: &'tcx Expr<'_>, + or_expr: &'tcx Expr<'_>, + map_expr: &'tcx Expr<'_>, +) { + if_chain! { + if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id); + if let Some(impl_id) = cx.tcx.impl_of_method(method_id); + if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Option); + if let ExprKind::Call(Expr { kind: ExprKind::Path(err_path), .. }, [err_arg]) = or_expr.kind; + if is_lang_ctor(cx, err_path, ResultErr); + if is_ok_wrapping(cx, map_expr); + if let Some(recv_snippet) = snippet_opt(cx, recv.span); + if let Some(err_arg_snippet) = snippet_opt(cx, err_arg.span); + if let Some(indent) = indent_of(cx, expr.span); + then { + let reindented_err_arg_snippet = reindent_multiline(err_arg_snippet.into(), true, Some(indent + 4)); + span_lint_and_sugg( + cx, + MANUAL_OK_OR, + expr.span, + "this pattern reimplements `Option::ok_or`", + "replace with", + format!( + "{}.ok_or({})", + recv_snippet, + reindented_err_arg_snippet + ), + Applicability::MachineApplicable, + ); + } + } +} + +fn is_ok_wrapping(cx: &LateContext<'_>, map_expr: &Expr<'_>) -> bool { + if let ExprKind::Path(ref qpath) = map_expr.kind { + if is_lang_ctor(cx, qpath, ResultOk) { + return true; + } + } + if_chain! { + if let ExprKind::Closure(&Closure { body, .. }) = map_expr.kind; + let body = cx.tcx.hir().body(body); + if let PatKind::Binding(_, param_id, ..) = body.params[0].pat.kind; + if let ExprKind::Call(Expr { kind: ExprKind::Path(ok_path), .. }, &[ref ok_arg]) = body.value.kind; + if is_lang_ctor(cx, ok_path, ResultOk); + then { path_to_local_id(ok_arg, param_id) } else { false } + } +} |