diff --git a/clippy_lints/src/methods/filter_map.rs b/clippy_lints/src/methods/filter_map.rs index 7cfd3d346b6..e489899c19e 100644 --- a/clippy_lints/src/methods/filter_map.rs +++ b/clippy_lints/src/methods/filter_map.rs @@ -26,13 +26,14 @@ fn is_method(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_name: Symbol) -> hir::ExprKind::Closure(&hir::Closure { body, .. }) => { let body = cx.tcx.hir().body(body); let closure_expr = peel_blocks(body.value); - let arg_id = body.params[0].pat.hir_id; match closure_expr.kind { hir::ExprKind::MethodCall(hir::PathSegment { ident, .. }, receiver, ..) => { if ident.name == method_name && let hir::ExprKind::Path(path) = &receiver.kind && let Res::Local(ref local) = cx.qpath_res(path, receiver.hir_id) + && !body.params.is_empty() { + let arg_id = body.params[0].pat.hir_id; return arg_id == *local; } false diff --git a/clippy_lints/src/methods/iter_filter.rs b/clippy_lints/src/methods/iter_filter.rs index ade8e3155fa..9f84321ced4 100644 --- a/clippy_lints/src/methods/iter_filter.rs +++ b/clippy_lints/src/methods/iter_filter.rs @@ -1,80 +1,181 @@ +use clippy_utils::ty::get_iterator_item_ty; +use hir::ExprKind; use rustc_lint::{LateContext, LintContext}; use super::{ITER_FILTER_IS_OK, ITER_FILTER_IS_SOME}; use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::source::{indent_of, reindent_multiline}; -use clippy_utils::{is_trait_method, peel_blocks, span_contains_comment}; +use clippy_utils::{get_parent_expr, is_trait_method, peel_blocks, span_contains_comment}; use rustc_errors::Applicability; use rustc_hir as hir; -use rustc_hir::def::Res; use rustc_hir::QPath; -use rustc_span::symbol::{sym, Symbol}; +use rustc_span::symbol::{sym, Ident, Symbol}; use rustc_span::Span; use std::borrow::Cow; -fn is_method(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_name: Symbol) -> bool { - match &expr.kind { - hir::ExprKind::Path(QPath::TypeRelative(_, mname)) => mname.ident.name == method_name, - hir::ExprKind::Path(QPath::Resolved(_, segments)) => { - segments.segments.last().unwrap().ident.name == method_name +/// +/// Returns true if the expression is a method call to `method_name` +/// e.g. `a.method_name()` or `Option::method_name`. +/// +/// The type-checker verifies for us that the method accepts the right kind of items +/// (e.g. `Option::is_some` accepts `Option<_>`), so we don't need to check that. +/// +/// How to capture each case: +/// +/// `.filter(|a| { std::option::Option::is_some(a) })` +/// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ <- this is a closure, getting unwrapped and +/// recursively checked. +/// `std::option::Option::is_some(a)` +/// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ <- this is a call. It unwraps to a path with +/// `QPath::TypeRelative`. Since this is a type relative path, we need to check the method name, the +/// type, and that the parameter of the closure is passed in the call. This part is the dual of +/// `receiver.method_name()` below. +/// +/// `filter(std::option::Option::is_some);` +/// ^^^^^^^^^^^^^^^^^^^^^^^^^^^ <- this is a type relative path, like above, we check the +/// type and the method name. +/// +/// `filter(|a| a.is_some());` +/// ^^^^^^^^^^^^^^^ <- this is a method call inside a closure, +/// we check that the parameter of the closure is the receiver of the method call and don't allow +/// any other parameters. +fn is_method( + cx: &LateContext<'_>, + expr: &hir::Expr<'_>, + type_symbol: Symbol, + method_name: Symbol, + params: &[&hir::Pat<'_>], +) -> bool { + fn pat_is_recv(ident: Ident, param: &hir::Pat<'_>) -> bool { + match param.kind { + hir::PatKind::Binding(_, _, other, _) => ident == other, + hir::PatKind::Ref(pat, _) => pat_is_recv(ident, pat), + _ => false, + } + } + match expr.kind { + hir::ExprKind::MethodCall(hir::PathSegment { ident, .. }, recv, ..) => { + // compare the identifier of the receiver to the parameter + // we are in a filter => closure has a single parameter and a single, non-block + // expression, this means that the parameter shadows all outside variables with + // the same name => avoid FPs. If the parameter is not the receiver, then this hits + // outside variables => avoid FP + if ident.name == method_name + && let ExprKind::Path(QPath::Resolved(None, path)) = recv.kind + && let &[seg] = path.segments + && params.iter().any(|p| pat_is_recv(seg.ident, p)) + { + return true; + } + false + }, + // This is used to check for complete paths via `|a| std::option::Option::is_some(a)` + // this then unwraps to a path with `QPath::TypeRelative` + // we pass the params as they've been passed to the current call through the closure + hir::ExprKind::Call(expr, [param]) => { + // this will hit the `QPath::TypeRelative` case and check that the method name is correct + if is_method(cx, expr, type_symbol, method_name, params) + // we then check that this is indeed passing the parameter of the closure + && let ExprKind::Path(QPath::Resolved(None, path)) = param.kind + && let &[seg] = path.segments + && params.iter().any(|p| pat_is_recv(seg.ident, p)) + { + return true; + } + false + }, + hir::ExprKind::Path(QPath::TypeRelative(ty, mname)) => { + let ty = cx.typeck_results().node_type(ty.hir_id); + if let Some(did) = cx.tcx.get_diagnostic_item(type_symbol) + && ty.ty_adt_def() == cx.tcx.type_of(did).skip_binder().ty_adt_def() + { + return mname.ident.name == method_name; + } + false }, - hir::ExprKind::MethodCall(segment, _, _, _) => segment.ident.name == method_name, hir::ExprKind::Closure(&hir::Closure { body, .. }) => { let body = cx.tcx.hir().body(body); let closure_expr = peel_blocks(body.value); - let arg_id = body.params[0].pat.hir_id; - match closure_expr.kind { - hir::ExprKind::MethodCall(hir::PathSegment { ident, .. }, receiver, ..) => { - if ident.name == method_name - && let hir::ExprKind::Path(path) = &receiver.kind - && let Res::Local(ref local) = cx.qpath_res(path, receiver.hir_id) - { - return arg_id == *local; - } - false - }, - _ => false, - } + let params = body.params.iter().map(|param| param.pat).collect::>(); + is_method(cx, closure_expr, type_symbol, method_name, params.as_slice()) }, _ => false, } } fn parent_is_map(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool { - if let hir::Node::Expr(parent_expr) = cx.tcx.hir().get_parent(expr.hir_id) { - is_method(cx, parent_expr, rustc_span::sym::map) - } else { - false + if let Some(expr) = get_parent_expr(cx, expr) + && is_trait_method(cx, expr, sym::Iterator) + && let hir::ExprKind::MethodCall(path, _, _, _) = expr.kind + && path.ident.name == rustc_span::sym::map + { + return true; } + false } -#[allow(clippy::too_many_arguments)] -pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, filter_arg: &hir::Expr<'_>, filter_span: Span) { - let is_iterator = is_trait_method(cx, expr, sym::Iterator); - let parent_is_not_map = !parent_is_map(cx, expr); +enum FilterType { + IsSome, + IsOk, +} - if is_iterator - && parent_is_not_map - && is_method(cx, filter_arg, sym!(is_some)) - && !span_contains_comment(cx.sess().source_map(), filter_span.with_hi(expr.span.hi())) +/// Returns the `FilterType` of the expression if it is a filter over an Iter