From 649d443646e8ca6efad73643dcc11b488ae60a79 Mon Sep 17 00:00:00 2001 From: Jason Newcomb Date: Thu, 28 Apr 2022 13:29:44 -0400 Subject: [PATCH] Replace `expr_visitor` with `for_each_expr` --- clippy_lints/src/implicit_return.rs | 12 +- clippy_lints/src/methods/str_splitn.rs | 20 ++- clippy_lints/src/needless_late_init.rs | 34 +++-- clippy_lints/src/panic_in_result_fn.rs | 19 +-- clippy_lints/src/read_zero_byte_vec.rs | 42 +++---- clippy_utils/src/lib.rs | 19 ++- clippy_utils/src/macros.rs | 79 +++++------- clippy_utils/src/ptr.rs | 37 +++--- clippy_utils/src/usage.rs | 49 +++----- clippy_utils/src/visitors.rs | 164 +++++++++++-------------- 10 files changed, 207 insertions(+), 268 deletions(-) diff --git a/clippy_lints/src/implicit_return.rs b/clippy_lints/src/implicit_return.rs index cfc988da233..946d04eff6f 100644 --- a/clippy_lints/src/implicit_return.rs +++ b/clippy_lints/src/implicit_return.rs @@ -2,10 +2,11 @@ diagnostics::span_lint_hir_and_then, get_async_fn_body, is_async_fn, source::{snippet_with_applicability, snippet_with_context, walk_span_to_context}, - visitors::expr_visitor_no_bodies, + visitors::for_each_expr, }; +use core::ops::ControlFlow; use rustc_errors::Applicability; -use rustc_hir::intravisit::{FnKind, Visitor}; +use rustc_hir::intravisit::FnKind; use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, FnRetTy, HirId}; use rustc_lint::{LateContext, LateLintPass, LintContext}; use rustc_middle::lint::in_external_macro; @@ -152,7 +153,7 @@ fn lint_implicit_returns( ExprKind::Loop(block, ..) => { let mut add_return = false; - expr_visitor_no_bodies(|e| { + let _: Option = for_each_expr(block, |e| { if let ExprKind::Break(dest, sub_expr) = e.kind { if dest.target_id.ok() == Some(expr.hir_id) { if call_site_span.is_none() && e.span.ctxt() == ctxt { @@ -167,9 +168,8 @@ fn lint_implicit_returns( } } } - true - }) - .visit_block(block); + ControlFlow::Continue(()) + }); if add_return { #[expect(clippy::option_if_let_else)] if let Some(span) = call_site_span { diff --git a/clippy_lints/src/methods/str_splitn.rs b/clippy_lints/src/methods/str_splitn.rs index 9ca4d65550d..ae3594bd36c 100644 --- a/clippy_lints/src/methods/str_splitn.rs +++ b/clippy_lints/src/methods/str_splitn.rs @@ -2,11 +2,11 @@ use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then}; use clippy_utils::source::snippet_with_context; use clippy_utils::usage::local_used_after_expr; -use clippy_utils::visitors::expr_visitor; +use clippy_utils::visitors::{for_each_expr_with_closures, Descend}; use clippy_utils::{is_diag_item_method, match_def_path, meets_msrv, msrvs, path_to_local_id, paths}; +use core::ops::ControlFlow; use if_chain::if_chain; use rustc_errors::Applicability; -use rustc_hir::intravisit::Visitor; use rustc_hir::{ BindingAnnotation, Expr, ExprKind, HirId, LangItem, Local, MatchSource, Node, Pat, PatKind, QPath, Stmt, StmtKind, }; @@ -211,7 +211,7 @@ fn indirect_usage<'tcx>( binding: HirId, ctxt: SyntaxContext, ) -> Option> { - if let StmtKind::Local(Local { + if let StmtKind::Local(&Local { pat: Pat { kind: PatKind::Binding(BindingAnnotation::NONE, _, ident, None), .. @@ -222,14 +222,12 @@ fn indirect_usage<'tcx>( }) = stmt.kind { let mut path_to_binding = None; - expr_visitor(cx, |expr| { - if path_to_local_id(expr, binding) { - path_to_binding = Some(expr); + let _: Option = for_each_expr_with_closures(cx, init_expr, |e| { + if path_to_local_id(e, binding) { + path_to_binding = Some(e); } - - path_to_binding.is_none() - }) - .visit_expr(init_expr); + ControlFlow::Continue(Descend::from(path_to_binding.is_none())) + }); let mut parents = cx.tcx.hir().parent_iter(path_to_binding?.hir_id); let iter_usage = parse_iter_usage(cx, ctxt, &mut parents)?; @@ -250,7 +248,7 @@ fn indirect_usage<'tcx>( .. } = iter_usage { - if parent_id == *local_hir_id { + if parent_id == local_hir_id { return Some(IndirectUsage { name: ident.name, span: stmt.span, diff --git a/clippy_lints/src/needless_late_init.rs b/clippy_lints/src/needless_late_init.rs index cbad53f4450..9d26e590086 100644 --- a/clippy_lints/src/needless_late_init.rs +++ b/clippy_lints/src/needless_late_init.rs @@ -2,9 +2,9 @@ use clippy_utils::path_to_local; use clippy_utils::source::snippet_opt; use clippy_utils::ty::needs_ordered_drop; -use clippy_utils::visitors::{expr_visitor, expr_visitor_no_bodies, is_local_used}; +use clippy_utils::visitors::{for_each_expr, for_each_expr_with_closures, is_local_used}; +use core::ops::ControlFlow; use rustc_errors::{Applicability, MultiSpan}; -use rustc_hir::intravisit::Visitor; use rustc_hir::{ BindingAnnotation, Block, Expr, ExprKind, HirId, Local, LocalSource, MatchSource, Node, Pat, PatKind, Stmt, StmtKind, @@ -64,31 +64,25 @@ declare_lint_pass!(NeedlessLateInit => [NEEDLESS_LATE_INIT]); fn contains_assign_expr<'tcx>(cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'tcx>) -> bool { - let mut seen = false; - expr_visitor(cx, |expr| { - if let ExprKind::Assign(..) = expr.kind { - seen = true; + for_each_expr_with_closures(cx, stmt, |e| { + if matches!(e.kind, ExprKind::Assign(..)) { + ControlFlow::Break(()) + } else { + ControlFlow::Continue(()) } - - !seen }) - .visit_stmt(stmt); - - seen + .is_some() } fn contains_let(cond: &Expr<'_>) -> bool { - let mut seen = false; - expr_visitor_no_bodies(|expr| { - if let ExprKind::Let(_) = expr.kind { - seen = true; + for_each_expr(cond, |e| { + if matches!(e.kind, ExprKind::Let(_)) { + ControlFlow::Break(()) + } else { + ControlFlow::Continue(()) } - - !seen }) - .visit_expr(cond); - - seen + .is_some() } fn stmt_needs_ordered_drop(cx: &LateContext<'_>, stmt: &Stmt<'_>) -> bool { diff --git a/clippy_lints/src/panic_in_result_fn.rs b/clippy_lints/src/panic_in_result_fn.rs index 4aa0d9227ab..efec12489a9 100644 --- a/clippy_lints/src/panic_in_result_fn.rs +++ b/clippy_lints/src/panic_in_result_fn.rs @@ -2,9 +2,10 @@ use clippy_utils::macros::root_macro_call_first_node; use clippy_utils::return_ty; use clippy_utils::ty::is_type_diagnostic_item; -use clippy_utils::visitors::expr_visitor_no_bodies; +use clippy_utils::visitors::{for_each_expr, Descend}; +use core::ops::ControlFlow; use rustc_hir as hir; -use rustc_hir::intravisit::{FnKind, Visitor}; +use rustc_hir::intravisit::FnKind; use rustc_lint::{LateContext, LateLintPass}; use rustc_session::{declare_lint_pass, declare_tool_lint}; use rustc_span::{sym, Span}; @@ -58,18 +59,20 @@ fn check_fn( fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir::Body<'tcx>) { let mut panics = Vec::new(); - expr_visitor_no_bodies(|expr| { - let Some(macro_call) = root_macro_call_first_node(cx, expr) else { return true }; + let _: Option = for_each_expr(body.value, |e| { + let Some(macro_call) = root_macro_call_first_node(cx, e) else { + return ControlFlow::Continue(Descend::Yes); + }; if matches!( cx.tcx.item_name(macro_call.def_id).as_str(), "unimplemented" | "unreachable" | "panic" | "todo" | "assert" | "assert_eq" | "assert_ne" ) { panics.push(macro_call.span); - return false; + ControlFlow::Continue(Descend::No) + } else { + ControlFlow::Continue(Descend::Yes) } - true - }) - .visit_expr(body.value); + }); if !panics.is_empty() { span_lint_and_then( cx, diff --git a/clippy_lints/src/read_zero_byte_vec.rs b/clippy_lints/src/read_zero_byte_vec.rs index ae80b6f1269..fa107858863 100644 --- a/clippy_lints/src/read_zero_byte_vec.rs +++ b/clippy_lints/src/read_zero_byte_vec.rs @@ -2,9 +2,10 @@ diagnostics::{span_lint, span_lint_and_sugg}, higher::{get_vec_init_kind, VecInitKind}, source::snippet, - visitors::expr_visitor_no_bodies, + visitors::for_each_expr, }; -use hir::{intravisit::Visitor, ExprKind, Local, PatKind, PathSegment, QPath, StmtKind}; +use core::ops::ControlFlow; +use hir::{Expr, ExprKind, Local, PatKind, PathSegment, QPath, StmtKind}; use rustc_errors::Applicability; use rustc_hir as hir; use rustc_lint::{LateContext, LateLintPass}; @@ -58,10 +59,8 @@ fn check_block(&mut self, cx: &LateContext<'tcx>, block: &hir::Block<'tcx>) { && let PatKind::Binding(_, _, ident, _) = pat.kind && let Some(vec_init_kind) = get_vec_init_kind(cx, init) { - // finds use of `_.read(&mut v)` - let mut read_found = false; - let mut visitor = expr_visitor_no_bodies(|expr| { - if let ExprKind::MethodCall(path, _self, [arg], _) = expr.kind + let visitor = |expr: &Expr<'_>| { + if let ExprKind::MethodCall(path, _, [arg], _) = expr.kind && let PathSegment { ident: read_or_read_exact, .. } = *path && matches!(read_or_read_exact.as_str(), "read" | "read_exact") && let ExprKind::AddrOf(_, hir::Mutability::Mut, inner) = arg.kind @@ -69,27 +68,22 @@ fn check_block(&mut self, cx: &LateContext<'tcx>, block: &hir::Block<'tcx>) { && let [inner_seg] = inner_path.segments && ident.name == inner_seg.ident.name { - read_found = true; - } - !read_found - }); - - let next_stmt_span; - if idx == block.stmts.len() - 1 { - // case { .. stmt; expr } - if let Some(e) = block.expr { - visitor.visit_expr(e); - next_stmt_span = e.span; + ControlFlow::Break(()) } else { - return; + ControlFlow::Continue(()) } - } else { + }; + + let (read_found, next_stmt_span) = + if let Some(next_stmt) = block.stmts.get(idx + 1) { // case { .. stmt; stmt; .. } - let next_stmt = &block.stmts[idx + 1]; - visitor.visit_stmt(next_stmt); - next_stmt_span = next_stmt.span; - } - drop(visitor); + (for_each_expr(next_stmt, visitor).is_some(), next_stmt.span) + } else if let Some(e) = block.expr { + // case { .. stmt; expr } + (for_each_expr(e, visitor).is_some(), e.span) + } else { + return + }; if read_found && !next_stmt_span.from_expansion() { let applicability = Applicability::MaybeIncorrect; diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs index 8f67fa109fc..3caa6380e09 100644 --- a/clippy_utils/src/lib.rs +++ b/clippy_utils/src/lib.rs @@ -3,6 +3,7 @@ #![feature(control_flow_enum)] #![feature(let_chains)] #![feature(lint_reasons)] +#![feature(never_type)] #![feature(once_cell)] #![feature(rustc_private)] #![recursion_limit = "512"] @@ -65,6 +66,7 @@ both, count_eq, eq_expr_value, hash_expr, hash_stmt, over, HirEqInterExpr, SpanlessEq, SpanlessHash, }; +use core::ops::ControlFlow; use std::collections::hash_map::Entry; use std::hash::BuildHasherDefault; use std::sync::OnceLock; @@ -113,7 +115,7 @@ use crate::consts::{constant, Constant}; use crate::ty::{can_partially_move_ty, expr_sig, is_copy, is_recursively_primitive_type, ty_is_fn_once_param}; -use crate::visitors::expr_visitor_no_bodies; +use crate::visitors::for_each_expr; pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option) -> Option { if let Ok(version) = RustcVersion::parse(msrv) { @@ -1193,17 +1195,14 @@ pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool { /// Returns `true` if `expr` contains a return expression pub fn contains_return(expr: &hir::Expr<'_>) -> bool { - let mut found = false; - expr_visitor_no_bodies(|expr| { - if !found { - if let hir::ExprKind::Ret(..) = &expr.kind { - found = true; - } + for_each_expr(expr, |e| { + if matches!(e.kind, hir::ExprKind::Ret(..)) { + ControlFlow::Break(()) + } else { + ControlFlow::Continue(()) } - !found }) - .visit_expr(expr); - found + .is_some() } /// Extends the span to the beginning of the spans line, incl. whitespaces. diff --git a/clippy_utils/src/macros.rs b/clippy_utils/src/macros.rs index 079c8f50f12..c0b87cd175e 100644 --- a/clippy_utils/src/macros.rs +++ b/clippy_utils/src/macros.rs @@ -2,7 +2,7 @@ use crate::is_path_diagnostic_item; use crate::source::snippet_opt; -use crate::visitors::expr_visitor_no_bodies; +use crate::visitors::{for_each_expr, Descend}; use arrayvec::ArrayVec; use itertools::{izip, Either, Itertools}; @@ -270,20 +270,19 @@ fn find_assert_args_inner<'a, const N: usize>( }; let mut args = ArrayVec::new(); let mut panic_expn = None; - expr_visitor_no_bodies(|e| { + let _: Option = for_each_expr(expr, |e| { if args.is_full() { if panic_expn.is_none() && e.span.ctxt() != expr.span.ctxt() { panic_expn = PanicExpn::parse(cx, e); } - panic_expn.is_none() + ControlFlow::Continue(Descend::from(panic_expn.is_none())) } else if is_assert_arg(cx, e, expn) { args.push(e); - false + ControlFlow::Continue(Descend::No) } else { - true + ControlFlow::Continue(Descend::Yes) } - }) - .visit_expr(expr); + }); let args = args.into_inner().ok()?; // if no `panic!(..)` is found, use `PanicExpn::Empty` // to indicate that the default assertion message is used @@ -297,22 +296,19 @@ fn find_assert_within_debug_assert<'a>( expn: ExpnId, assert_name: Symbol, ) -> Option<(&'a Expr<'a>, ExpnId)> { - let mut found = None; - expr_visitor_no_bodies(|e| { - if found.is_some() || !e.span.from_expansion() { - return false; + for_each_expr(expr, |e| { + if !e.span.from_expansion() { + return ControlFlow::Continue(Descend::No); } let e_expn = e.span.ctxt().outer_expn(); if e_expn == expn { - return true; + ControlFlow::Continue(Descend::Yes) + } else if e_expn.expn_data().macro_def_id.map(|id| cx.tcx.item_name(id)) == Some(assert_name) { + ControlFlow::Break((e, e_expn)) + } else { + ControlFlow::Continue(Descend::No) } - if e_expn.expn_data().macro_def_id.map(|id| cx.tcx.item_name(id)) == Some(assert_name) { - found = Some((e, e_expn)); - } - false }) - .visit_expr(expr); - found } fn is_assert_arg(cx: &LateContext<'_>, expr: &Expr<'_>, assert_expn: ExpnId) -> bool { @@ -396,16 +392,14 @@ fn new(cx: &LateContext<'_>, pieces: &Expr<'_>) -> Option { }); let mut parts = Vec::new(); - expr_visitor_no_bodies(|expr| { - if let ExprKind::Lit(lit) = &expr.kind { - if let LitKind::Str(symbol, _) = lit.node { - parts.push(symbol); - } + let _: Option = for_each_expr(pieces, |expr| { + if let ExprKind::Lit(lit) = &expr.kind + && let LitKind::Str(symbol, _) = lit.node + { + parts.push(symbol); } - - true - }) - .visit_expr(pieces); + ControlFlow::Continue(()) + }); Some(Self { span, @@ -431,7 +425,7 @@ impl<'tcx> FormatArgsValues<'tcx> { fn new(args: &'tcx Expr<'tcx>, format_string_span: SpanData) -> Self { let mut pos_to_value_index = Vec::new(); let mut value_args = Vec::new(); - expr_visitor_no_bodies(|expr| { + let _: Option = for_each_expr(args, |expr| { if expr.span.ctxt() == args.span.ctxt() { // ArgumentV1::new_() // ArgumentV1::from_usize() @@ -453,16 +447,13 @@ fn new(args: &'tcx Expr<'tcx>, format_string_span: SpanData) -> Self { pos_to_value_index.push(val_idx); } - - true + ControlFlow::Continue(Descend::Yes) } else { // assume that any expr with a differing span is a value value_args.push(expr); - - false + ControlFlow::Continue(Descend::No) } - }) - .visit_expr(args); + }); Self { value_args, @@ -866,22 +857,18 @@ pub fn parse(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option { } pub fn find_nested(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expn_id: ExpnId) -> Option { - let mut format_args = None; - expr_visitor_no_bodies(|e| { - if format_args.is_some() { - return false; - } + for_each_expr(expr, |e| { let e_ctxt = e.span.ctxt(); if e_ctxt == expr.span.ctxt() { - return true; + ControlFlow::Continue(Descend::Yes) + } else if e_ctxt.outer_expn().is_descendant_of(expn_id) + && let Some(args) = FormatArgsExpn::parse(cx, e) + { + ControlFlow::Break(args) + } else { + ControlFlow::Continue(Descend::No) } - if e_ctxt.outer_expn().is_descendant_of(expn_id) { - format_args = FormatArgsExpn::parse(cx, e); - } - false }) - .visit_expr(expr); - format_args } /// Source callsite span of all inputs diff --git a/clippy_utils/src/ptr.rs b/clippy_utils/src/ptr.rs index 0226f74906b..88837d8a143 100644 --- a/clippy_utils/src/ptr.rs +++ b/clippy_utils/src/ptr.rs @@ -1,7 +1,7 @@ use crate::source::snippet; -use crate::visitors::expr_visitor_no_bodies; +use crate::visitors::{for_each_expr, Descend}; use crate::{path_to_local_id, strip_pat_refs}; -use rustc_hir::intravisit::Visitor; +use core::ops::ControlFlow; use rustc_hir::{Body, BodyId, ExprKind, HirId, PatKind}; use rustc_lint::LateContext; use rustc_span::Span; @@ -30,28 +30,23 @@ fn extract_clone_suggestions<'tcx>( replace: &[(&'static str, &'static str)], body: &'tcx Body<'_>, ) -> Option)>> { - let mut abort = false; let mut spans = Vec::new(); - expr_visitor_no_bodies(|expr| { - if abort { - return false; - } - if let ExprKind::MethodCall(seg, recv, [], _) = expr.kind { - if path_to_local_id(recv, id) { - if seg.ident.name.as_str() == "capacity" { - abort = true; - return false; - } - for &(fn_name, suffix) in replace { - if seg.ident.name.as_str() == fn_name { - spans.push((expr.span, snippet(cx, recv.span, "_") + suffix)); - return false; - } + for_each_expr(body, |e| { + if let ExprKind::MethodCall(seg, recv, [], _) = e.kind + && path_to_local_id(recv, id) + { + if seg.ident.as_str() == "capacity" { + return ControlFlow::Break(()); + } + for &(fn_name, suffix) in replace { + if seg.ident.as_str() == fn_name { + spans.push((e.span, snippet(cx, recv.span, "_") + suffix)); + return ControlFlow::Continue(Descend::No); } } } - !abort + ControlFlow::Continue(Descend::Yes) }) - .visit_body(body); - if abort { None } else { Some(spans) } + .is_none() + .then_some(spans) } diff --git a/clippy_utils/src/usage.rs b/clippy_utils/src/usage.rs index 3221b82aed4..b5ec3fef3e0 100644 --- a/clippy_utils/src/usage.rs +++ b/clippy_utils/src/usage.rs @@ -1,5 +1,6 @@ use crate as utils; -use crate::visitors::{expr_visitor, expr_visitor_no_bodies}; +use crate::visitors::{for_each_expr, for_each_expr_with_closures, Descend}; +use core::ops::ControlFlow; use rustc_hir as hir; use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::HirIdSet; @@ -148,28 +149,17 @@ fn nested_visit_map(&mut self) -> Self::Map { } pub fn contains_return_break_continue_macro(expression: &Expr<'_>) -> bool { - let mut seen_return_break_continue = false; - expr_visitor_no_bodies(|ex| { - if seen_return_break_continue { - return false; - } - match &ex.kind { - ExprKind::Ret(..) | ExprKind::Break(..) | ExprKind::Continue(..) => { - seen_return_break_continue = true; - }, + for_each_expr(expression, |e| { + match e.kind { + ExprKind::Ret(..) | ExprKind::Break(..) | ExprKind::Continue(..) => ControlFlow::Break(()), // Something special could be done here to handle while or for loop // desugaring, as this will detect a break if there's a while loop // or a for loop inside the expression. - _ => { - if ex.span.from_expansion() { - seen_return_break_continue = true; - } - }, + _ if e.span.from_expansion() => ControlFlow::Break(()), + _ => ControlFlow::Continue(()), } - !seen_return_break_continue }) - .visit_expr(expression); - seen_return_break_continue + .is_some() } pub fn local_used_after_expr(cx: &LateContext<'_>, local_id: HirId, after: &Expr<'_>) -> bool { @@ -200,23 +190,16 @@ pub fn local_used_after_expr(cx: &LateContext<'_>, local_id: HirId, after: &Expr return true; } - let mut used_after_expr = false; let mut past_expr = false; - expr_visitor(cx, |expr| { - if used_after_expr { - return false; - } - - if expr.hir_id == after.hir_id { + for_each_expr_with_closures(cx, block, |e| { + if e.hir_id == after.hir_id { past_expr = true; - return false; + ControlFlow::Continue(Descend::No) + } else if past_expr && utils::path_to_local_id(e, local_id) { + ControlFlow::Break(()) + } else { + ControlFlow::Continue(Descend::Yes) } - - if past_expr && utils::path_to_local_id(expr, local_id) { - used_after_expr = true; - } - !used_after_expr }) - .visit_block(block); - used_after_expr + .is_some() } diff --git a/clippy_utils/src/visitors.rs b/clippy_utils/src/visitors.rs index 232d571902b..d4294f18fd5 100644 --- a/clippy_utils/src/visitors.rs +++ b/clippy_utils/src/visitors.rs @@ -5,14 +5,13 @@ use rustc_hir::def::{CtorKind, DefKind, Res}; use rustc_hir::intravisit::{self, walk_block, walk_expr, Visitor}; use rustc_hir::{ - Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, Let, Pat, QPath, Stmt, UnOp, - UnsafeSource, Unsafety, + AnonConst, Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, Let, Pat, QPath, + Stmt, UnOp, UnsafeSource, Unsafety, }; use rustc_lint::LateContext; -use rustc_middle::hir::map::Map; use rustc_middle::hir::nested_filter; use rustc_middle::ty::adjustment::Adjust; -use rustc_middle::ty::{self, Ty, TypeckResults}; +use rustc_middle::ty::{self, Ty, TyCtxt, TypeckResults}; use rustc_span::Span; mod internal { @@ -48,6 +47,26 @@ fn descend(&self) -> bool { } } +/// A type which can be visited. +pub trait Visitable<'tcx> { + /// Calls the corresponding `visit_*` function on the visitor. + fn visit>(self, visitor: &mut V); +} +macro_rules! visitable_ref { + ($t:ident, $f:ident) => { + impl<'tcx> Visitable<'tcx> for &'tcx $t<'tcx> { + fn visit>(self, visitor: &mut V) { + visitor.$f(self); + } + } + }; +} +visitable_ref!(Arm, visit_arm); +visitable_ref!(Block, visit_block); +visitable_ref!(Body, visit_body); +visitable_ref!(Expr, visit_expr); +visitable_ref!(Stmt, visit_stmt); + /// Calls the given function once for each expression contained. This does not enter any bodies or /// nested items. pub fn for_each_expr<'tcx, B, C: Continue>( @@ -82,57 +101,63 @@ fn visit_nested_item(&mut self, _: ItemId) {} v.res } -/// Convenience method for creating a `Visitor` with just `visit_expr` overridden and nested -/// bodies (i.e. closures) are visited. -/// If the callback returns `true`, the expr just provided to the callback is walked. -#[must_use] -pub fn expr_visitor<'tcx>(cx: &LateContext<'tcx>, f: impl FnMut(&'tcx Expr<'tcx>) -> bool) -> impl Visitor<'tcx> { - struct V<'tcx, F> { - hir: Map<'tcx>, +/// Calls the given function once for each expression contained. This will enter bodies, but not +/// nested items. +pub fn for_each_expr_with_closures<'tcx, B, C: Continue>( + cx: &LateContext<'tcx>, + node: impl Visitable<'tcx>, + f: impl FnMut(&'tcx Expr<'tcx>) -> ControlFlow, +) -> Option { + struct V<'tcx, B, F> { + tcx: TyCtxt<'tcx>, f: F, + res: Option, } - impl<'tcx, F: FnMut(&'tcx Expr<'tcx>) -> bool> Visitor<'tcx> for V<'tcx, F> { + impl<'tcx, B, C: Continue, F: FnMut(&'tcx Expr<'tcx>) -> ControlFlow> Visitor<'tcx> for V<'tcx, B, F> { type NestedFilter = nested_filter::OnlyBodies; fn nested_visit_map(&mut self) -> Self::Map { - self.hir + self.tcx.hir() } - fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) { - if (self.f)(expr) { - walk_expr(self, expr); + fn visit_expr(&mut self, e: &'tcx Expr<'tcx>) { + if self.res.is_some() { + return; + } + match (self.f)(e) { + ControlFlow::Continue(c) if c.descend() => walk_expr(self, e), + ControlFlow::Break(b) => self.res = Some(b), + ControlFlow::Continue(_) => (), } } - } - V { hir: cx.tcx.hir(), f } -} -/// Convenience method for creating a `Visitor` with just `visit_expr` overridden and nested -/// bodies (i.e. closures) are not visited. -/// If the callback returns `true`, the expr just provided to the callback is walked. -#[must_use] -pub fn expr_visitor_no_bodies<'tcx>(f: impl FnMut(&'tcx Expr<'tcx>) -> bool) -> impl Visitor<'tcx> { - struct V(F); - impl<'tcx, F: FnMut(&'tcx Expr<'tcx>) -> bool> Visitor<'tcx> for V { - fn visit_expr(&mut self, e: &'tcx Expr<'_>) { - if (self.0)(e) { - walk_expr(self, e); - } - } + // Only walk closures + fn visit_anon_const(&mut self, _: &'tcx AnonConst) {} + // Avoid unnecessary `walk_*` calls. + fn visit_ty(&mut self, _: &'tcx hir::Ty<'tcx>) {} + fn visit_pat(&mut self, _: &'tcx Pat<'tcx>) {} + fn visit_qpath(&mut self, _: &'tcx QPath<'tcx>, _: HirId, _: Span) {} + // Avoid monomorphising all `visit_*` functions. + fn visit_nested_item(&mut self, _: ItemId) {} } - V(f) + let mut v = V { + tcx: cx.tcx, + f, + res: None, + }; + node.visit(&mut v); + v.res } /// returns `true` if expr contains match expr desugared from try fn contains_try(expr: &hir::Expr<'_>) -> bool { - let mut found = false; - expr_visitor_no_bodies(|e| { - if !found { - found = matches!(e.kind, hir::ExprKind::Match(_, _, hir::MatchSource::TryDesugar)); + for_each_expr(expr, |e| { + if matches!(e.kind, hir::ExprKind::Match(_, _, hir::MatchSource::TryDesugar)) { + ControlFlow::Break(()) + } else { + ControlFlow::Continue(()) } - !found }) - .visit_expr(expr); - found + .is_some() } pub fn find_all_ret_expressions<'hir, F>(_cx: &LateContext<'_>, expr: &'hir hir::Expr<'hir>, callback: F) -> bool @@ -228,68 +253,29 @@ fn visit_expr(&mut self, expr: &'hir hir::Expr<'_>) { } } -/// A type which can be visited. -pub trait Visitable<'tcx> { - /// Calls the corresponding `visit_*` function on the visitor. - fn visit>(self, visitor: &mut V); -} -macro_rules! visitable_ref { - ($t:ident, $f:ident) => { - impl<'tcx> Visitable<'tcx> for &'tcx $t<'tcx> { - fn visit>(self, visitor: &mut V) { - visitor.$f(self); - } - } - }; -} -visitable_ref!(Arm, visit_arm); -visitable_ref!(Block, visit_block); -visitable_ref!(Body, visit_body); -visitable_ref!(Expr, visit_expr); -visitable_ref!(Stmt, visit_stmt); - -// impl<'tcx, I: IntoIterator> Visitable<'tcx> for I -// where -// I::Item: Visitable<'tcx>, -// { -// fn visit>(self, visitor: &mut V) { -// for x in self { -// x.visit(visitor); -// } -// } -// } - /// Checks if the given resolved path is used in the given body. pub fn is_res_used(cx: &LateContext<'_>, res: Res, body: BodyId) -> bool { - let mut found = false; - expr_visitor(cx, |e| { - if found { - return false; - } - + for_each_expr_with_closures(cx, cx.tcx.hir().body(body).value, |e| { if let ExprKind::Path(p) = &e.kind { if cx.qpath_res(p, e.hir_id) == res { - found = true; + return ControlFlow::Break(()); } } - !found + ControlFlow::Continue(()) }) - .visit_expr(cx.tcx.hir().body(body).value); - found + .is_some() } /// Checks if the given local is used. pub fn is_local_used<'tcx>(cx: &LateContext<'tcx>, visitable: impl Visitable<'tcx>, id: HirId) -> bool { - let mut is_used = false; - let mut visitor = expr_visitor(cx, |expr| { - if !is_used { - is_used = path_to_local_id(expr, id); + for_each_expr_with_closures(cx, visitable, |e| { + if path_to_local_id(e, id) { + ControlFlow::Break(()) + } else { + ControlFlow::Continue(()) } - !is_used - }); - visitable.visit(&mut visitor); - drop(visitor); - is_used + }) + .is_some() } /// Checks if the given expression is a constant.