X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fentry.rs;h=627f746ec99716fd6510ba61cbd7b0912c327e53;hb=b1786f62edf8bc20de33a36973ffb307a13962f5;hp=f625058b6703cec269e01a9f2c0da9b8e4f2e9fe;hpb=7c15f30701d636a7699a7ba8e7d683c351a4bb0a;p=rust.git diff --git a/clippy_lints/src/entry.rs b/clippy_lints/src/entry.rs index f625058b670..627f746ec99 100644 --- a/clippy_lints/src/entry.rs +++ b/clippy_lints/src/entry.rs @@ -1,33 +1,41 @@ -use crate::utils::SpanlessEq; -use crate::utils::{get_item_name, higher, is_type_diagnostic_item, match_type, paths, snippet, snippet_opt}; -use crate::utils::{snippet_with_applicability, span_lint_and_then, walk_ptrs_ty}; -use if_chain::if_chain; +use clippy_utils::higher; +use clippy_utils::{ + can_move_expr_to_closure_no_visit, + diagnostics::span_lint_and_sugg, + is_expr_final_block_expr, is_expr_used_or_unified, match_def_path, paths, peel_hir_expr_while, + source::{reindent_multiline, snippet_indent, snippet_with_applicability, snippet_with_context}, + SpanlessEq, +}; +use core::fmt::Write; use rustc_errors::Applicability; -use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor}; -use rustc_hir::{BorrowKind, Expr, ExprKind, UnOp}; +use rustc_hir::{ + intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor}, + Block, Expr, ExprKind, Guard, HirId, Local, Stmt, StmtKind, UnOp, +}; use rustc_lint::{LateContext, LateLintPass}; -use rustc_middle::hir::map::Map; use rustc_session::{declare_lint_pass, declare_tool_lint}; -use rustc_span::source_map::Span; +use rustc_span::{Span, SyntaxContext, DUMMY_SP}; declare_clippy_lint! { - /// **What it does:** Checks for uses of `contains_key` + `insert` on `HashMap` + /// ### What it does + /// Checks for uses of `contains_key` + `insert` on `HashMap` /// or `BTreeMap`. /// - /// **Why is this bad?** Using `entry` is more efficient. + /// ### Why is this bad? + /// Using `entry` is more efficient. /// - /// **Known problems:** Some false negatives, eg.: + /// ### Known problems + /// The suggestion may have type inference errors in some cases. e.g. /// ```rust - /// # use std::collections::HashMap; - /// # let mut map = HashMap::new(); - /// # let v = 1; - /// # let k = 1; - /// if !map.contains_key(&k) { - /// map.insert(k.clone(), v); - /// } + /// let mut map = std::collections::HashMap::new(); + /// let _ = if !map.contains_key(&0) { + /// map.insert(0, 0) + /// } else { + /// None + /// }; /// ``` /// - /// **Example:** + /// ### Example /// ```rust /// # use std::collections::HashMap; /// # let mut map = HashMap::new(); @@ -52,136 +60,586 @@ declare_lint_pass!(HashMapPass => [MAP_ENTRY]); -impl<'a, 'tcx> LateLintPass<'a, 'tcx> for HashMapPass { - fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) { - if let Some((ref check, ref then_block, ref else_block)) = higher::if_block(&expr) { - if let ExprKind::Unary(UnOp::UnNot, ref check) = check.kind { - if let Some((ty, map, key)) = check_cond(cx, check) { - // in case of `if !m.contains_key(&k) { m.insert(k, v); }` - // we can give a better error message - let sole_expr = { - else_block.is_none() - && if let ExprKind::Block(ref then_block, _) = then_block.kind { - (then_block.expr.is_some() as usize) + then_block.stmts.len() == 1 - } else { - true - } - // XXXManishearth we can also check for if/else blocks containing `None`. - }; - - let mut visitor = InsertVisitor { - cx, - span: expr.span, - ty, - map, - key, - sole_expr, - }; - - walk_expr(&mut visitor, &**then_block); +impl<'tcx> LateLintPass<'tcx> for HashMapPass { + #[allow(clippy::too_many_lines)] + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + let (cond_expr, then_expr, else_expr) = match higher::If::hir(expr) { + Some(higher::If { cond, then, r#else }) => (cond, then, r#else), + _ => return, + }; + + let (map_ty, contains_expr) = match try_parse_contains(cx, cond_expr) { + Some(x) => x, + None => return, + }; + + let then_search = match find_insert_calls(cx, &contains_expr, then_expr) { + Some(x) => x, + None => return, + }; + + let mut app = Applicability::MachineApplicable; + let map_str = snippet_with_context(cx, contains_expr.map.span, contains_expr.call_ctxt, "..", &mut app).0; + let key_str = snippet_with_context(cx, contains_expr.key.span, contains_expr.call_ctxt, "..", &mut app).0; + let sugg = if let Some(else_expr) = else_expr { + let else_search = match find_insert_calls(cx, &contains_expr, else_expr) { + Some(search) => search, + None => return, + }; + + if then_search.edits.is_empty() && else_search.edits.is_empty() { + // No insertions + return; + } else if then_search.edits.is_empty() || else_search.edits.is_empty() { + // if .. { insert } else { .. } or if .. { .. } else { insert } + let ((then_str, entry_kind), else_str) = match (else_search.edits.is_empty(), contains_expr.negated) { + (true, true) => ( + then_search.snippet_vacant(cx, then_expr.span, &mut app), + snippet_with_applicability(cx, else_expr.span, "{ .. }", &mut app), + ), + (true, false) => ( + then_search.snippet_occupied(cx, then_expr.span, &mut app), + snippet_with_applicability(cx, else_expr.span, "{ .. }", &mut app), + ), + (false, true) => ( + else_search.snippet_occupied(cx, else_expr.span, &mut app), + snippet_with_applicability(cx, then_expr.span, "{ .. }", &mut app), + ), + (false, false) => ( + else_search.snippet_vacant(cx, else_expr.span, &mut app), + snippet_with_applicability(cx, then_expr.span, "{ .. }", &mut app), + ), + }; + format!( + "if let {}::{} = {}.entry({}) {} else {}", + map_ty.entry_path(), + entry_kind, + map_str, + key_str, + then_str, + else_str, + ) + } else { + // if .. { insert } else { insert } + let ((then_str, then_entry), (else_str, else_entry)) = if contains_expr.negated { + ( + then_search.snippet_vacant(cx, then_expr.span, &mut app), + else_search.snippet_occupied(cx, else_expr.span, &mut app), + ) + } else { + ( + then_search.snippet_occupied(cx, then_expr.span, &mut app), + else_search.snippet_vacant(cx, else_expr.span, &mut app), + ) + }; + let indent_str = snippet_indent(cx, expr.span); + let indent_str = indent_str.as_deref().unwrap_or(""); + format!( + "match {}.entry({}) {{\n{indent} {entry}::{} => {}\n\ + {indent} {entry}::{} => {}\n{indent}}}", + map_str, + key_str, + then_entry, + reindent_multiline(then_str.into(), true, Some(4 + indent_str.len())), + else_entry, + reindent_multiline(else_str.into(), true, Some(4 + indent_str.len())), + entry = map_ty.entry_path(), + indent = indent_str, + ) + } + } else { + if then_search.edits.is_empty() { + // no insertions + return; + } + + // if .. { insert } + if !then_search.allow_insert_closure { + let (body_str, entry_kind) = if contains_expr.negated { + then_search.snippet_vacant(cx, then_expr.span, &mut app) + } else { + then_search.snippet_occupied(cx, then_expr.span, &mut app) + }; + format!( + "if let {}::{} = {}.entry({}) {}", + map_ty.entry_path(), + entry_kind, + map_str, + key_str, + body_str, + ) + } else if let Some(insertion) = then_search.as_single_insertion() { + let value_str = snippet_with_context(cx, insertion.value.span, then_expr.span.ctxt(), "..", &mut app).0; + if contains_expr.negated { + if insertion.value.can_have_side_effects() { + format!("{}.entry({}).or_insert_with(|| {});", map_str, key_str, value_str) + } else { + format!("{}.entry({}).or_insert({});", map_str, key_str, value_str) + } + } else { + // TODO: suggest using `if let Some(v) = map.get_mut(k) { .. }` here. + // This would need to be a different lint. + return; } - } else if let Some(ref else_block) = *else_block { - if let Some((ty, map, key)) = check_cond(cx, check) { - let mut visitor = InsertVisitor { - cx, - span: expr.span, - ty, - map, - key, - sole_expr: false, - }; - - walk_expr(&mut visitor, else_block); + } else { + let block_str = then_search.snippet_closure(cx, then_expr.span, &mut app); + if contains_expr.negated { + format!("{}.entry({}).or_insert_with(|| {});", map_str, key_str, block_str) + } else { + // TODO: suggest using `if let Some(v) = map.get_mut(k) { .. }` here. + // This would need to be a different lint. + return; } } - } + }; + + span_lint_and_sugg( + cx, + MAP_ENTRY, + expr.span, + &format!("usage of `contains_key` followed by `insert` on a `{}`", map_ty.name()), + "try this", + sugg, + app, + ); } } -fn check_cond<'a, 'tcx, 'b>( - cx: &'a LateContext<'a, 'tcx>, - check: &'b Expr<'b>, -) -> Option<(&'static str, &'b Expr<'b>, &'b Expr<'b>)> { - if_chain! { - if let ExprKind::MethodCall(ref path, _, ref params, _) = check.kind; - if params.len() >= 2; - if path.ident.name == sym!(contains_key); - if let ExprKind::AddrOf(BorrowKind::Ref, _, ref key) = params[1].kind; - then { - let map = ¶ms[0]; - let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(map)); +#[derive(Clone, Copy)] +enum MapType { + Hash, + BTree, +} +impl MapType { + fn name(self) -> &'static str { + match self { + Self::Hash => "HashMap", + Self::BTree => "BTreeMap", + } + } + fn entry_path(self) -> &'static str { + match self { + Self::Hash => "std::collections::hash_map::Entry", + Self::BTree => "std::collections::btree_map::Entry", + } + } +} - return if match_type(cx, obj_ty, &paths::BTREEMAP) { - Some(("BTreeMap", map, key)) - } - else if is_type_diagnostic_item(cx, obj_ty, sym!(hashmap_type)) { - Some(("HashMap", map, key)) - } - else { - None +struct ContainsExpr<'tcx> { + negated: bool, + map: &'tcx Expr<'tcx>, + key: &'tcx Expr<'tcx>, + call_ctxt: SyntaxContext, +} +fn try_parse_contains(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Option<(MapType, ContainsExpr<'tcx>)> { + let mut negated = false; + let expr = peel_hir_expr_while(expr, |e| match e.kind { + ExprKind::Unary(UnOp::Not, e) => { + negated = !negated; + Some(e) + }, + _ => None, + }); + match expr.kind { + ExprKind::MethodCall( + _, + _, + [map, Expr { + kind: ExprKind::AddrOf(_, _, key), + span: key_span, + .. + }], + _, + ) if key_span.ctxt() == expr.span.ctxt() => { + let id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?; + let expr = ContainsExpr { + negated, + map, + key, + call_ctxt: expr.span.ctxt(), }; + if match_def_path(cx, id, &paths::BTREEMAP_CONTAINS_KEY) { + Some((MapType::BTree, expr)) + } else if match_def_path(cx, id, &paths::HASHMAP_CONTAINS_KEY) { + Some((MapType::Hash, expr)) + } else { + None + } + }, + _ => None, + } +} + +struct InsertExpr<'tcx> { + map: &'tcx Expr<'tcx>, + key: &'tcx Expr<'tcx>, + value: &'tcx Expr<'tcx>, +} +fn try_parse_insert(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option> { + if let ExprKind::MethodCall(_, _, [map, key, value], _) = expr.kind { + let id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?; + if match_def_path(cx, id, &paths::BTREEMAP_INSERT) || match_def_path(cx, id, &paths::HASHMAP_INSERT) { + Some(InsertExpr { map, key, value }) + } else { + None } + } else { + None } +} + +/// An edit that will need to be made to move the expression to use the entry api +#[derive(Clone, Copy)] +enum Edit<'tcx> { + /// A semicolon that needs to be removed. Used to create a closure for `insert_with`. + RemoveSemi(Span), + /// An insertion into the map. + Insertion(Insertion<'tcx>), +} +impl Edit<'tcx> { + fn as_insertion(self) -> Option> { + if let Self::Insertion(i) = self { Some(i) } else { None } + } +} +#[derive(Clone, Copy)] +struct Insertion<'tcx> { + call: &'tcx Expr<'tcx>, + value: &'tcx Expr<'tcx>, +} - None +/// This visitor needs to do a multiple things: +/// * Find all usages of the map. An insertion can only be made before any other usages of the map. +/// * Determine if there's an insertion using the same key. There's no need for the entry api +/// otherwise. +/// * Determine if the final statement executed is an insertion. This is needed to use +/// `or_insert_with`. +/// * Determine if there's any sub-expression that can't be placed in a closure. +/// * Determine if there's only a single insert statement. `or_insert` can be used in this case. +#[allow(clippy::struct_excessive_bools)] +struct InsertSearcher<'cx, 'tcx> { + cx: &'cx LateContext<'tcx>, + /// The map expression used in the contains call. + map: &'tcx Expr<'tcx>, + /// The key expression used in the contains call. + key: &'tcx Expr<'tcx>, + /// The context of the top level block. All insert calls must be in the same context. + ctxt: SyntaxContext, + /// Whether this expression can be safely moved into a closure. + allow_insert_closure: bool, + /// Whether this expression can use the entry api. + can_use_entry: bool, + /// Whether this expression is the final expression in this code path. This may be a statement. + in_tail_pos: bool, + // Is this expression a single insert. A slightly better suggestion can be made in this case. + is_single_insert: bool, + /// If the visitor has seen the map being used. + is_map_used: bool, + /// The locations where changes need to be made for the suggestion. + edits: Vec>, + /// A stack of loops the visitor is currently in. + loops: Vec, } +impl<'tcx> InsertSearcher<'_, 'tcx> { + /// Visit the expression as a branch in control flow. Multiple insert calls can be used, but + /// only if they are on separate code paths. This will return whether the map was used in the + /// given expression. + fn visit_cond_arm(&mut self, e: &'tcx Expr<'_>) -> bool { + let is_map_used = self.is_map_used; + let in_tail_pos = self.in_tail_pos; + self.visit_expr(e); + let res = self.is_map_used; + self.is_map_used = is_map_used; + self.in_tail_pos = in_tail_pos; + res + } -struct InsertVisitor<'a, 'tcx, 'b> { - cx: &'a LateContext<'a, 'tcx>, - span: Span, - ty: &'static str, - map: &'b Expr<'b>, - key: &'b Expr<'b>, - sole_expr: bool, + /// Visits an expression which is not itself in a tail position, but other sibling expressions + /// may be. e.g. if conditions + fn visit_non_tail_expr(&mut self, e: &'tcx Expr<'_>) { + let in_tail_pos = self.in_tail_pos; + self.in_tail_pos = false; + self.visit_expr(e); + self.in_tail_pos = in_tail_pos; + } } +impl<'tcx> Visitor<'tcx> for InsertSearcher<'_, 'tcx> { + type Map = ErasedMap<'tcx>; + fn nested_visit_map(&mut self) -> NestedVisitorMap { + NestedVisitorMap::None + } + + fn visit_stmt(&mut self, stmt: &'tcx Stmt<'_>) { + match stmt.kind { + StmtKind::Semi(e) => { + self.visit_expr(e); + + if self.in_tail_pos && self.allow_insert_closure { + // The spans are used to slice the top level expression into multiple parts. This requires that + // they all come from the same part of the source code. + if stmt.span.ctxt() == self.ctxt && e.span.ctxt() == self.ctxt { + self.edits + .push(Edit::RemoveSemi(stmt.span.trim_start(e.span).unwrap_or(DUMMY_SP))); + } else { + self.allow_insert_closure = false; + } + } + }, + StmtKind::Expr(e) => self.visit_expr(e), + StmtKind::Local(Local { init: Some(e), .. }) => { + self.allow_insert_closure &= !self.in_tail_pos; + self.in_tail_pos = false; + self.is_single_insert = false; + self.visit_expr(e); + }, + _ => { + self.allow_insert_closure &= !self.in_tail_pos; + self.is_single_insert = false; + }, + } + } -impl<'a, 'tcx, 'b> Visitor<'tcx> for InsertVisitor<'a, 'tcx, 'b> { - type Map = Map<'tcx>; + fn visit_block(&mut self, block: &'tcx Block<'_>) { + // If the block is in a tail position, then the last expression (possibly a statement) is in the + // tail position. The rest, however, are not. + match (block.stmts, block.expr) { + ([], None) => { + self.allow_insert_closure &= !self.in_tail_pos; + }, + ([], Some(expr)) => self.visit_expr(expr), + (stmts, Some(expr)) => { + let in_tail_pos = self.in_tail_pos; + self.in_tail_pos = false; + for stmt in stmts { + self.visit_stmt(stmt); + } + self.in_tail_pos = in_tail_pos; + self.visit_expr(expr); + }, + ([stmts @ .., stmt], None) => { + let in_tail_pos = self.in_tail_pos; + self.in_tail_pos = false; + for stmt in stmts { + self.visit_stmt(stmt); + } + self.in_tail_pos = in_tail_pos; + self.visit_stmt(stmt); + }, + } + } fn visit_expr(&mut self, expr: &'tcx Expr<'_>) { - if_chain! { - if let ExprKind::MethodCall(ref path, _, ref params, _) = expr.kind; - if params.len() == 3; - if path.ident.name == sym!(insert); - if get_item_name(self.cx, self.map) == get_item_name(self.cx, ¶ms[0]); - if SpanlessEq::new(self.cx).eq_expr(self.key, ¶ms[1]); - if snippet_opt(self.cx, self.map.span) == snippet_opt(self.cx, params[0].span); - then { - span_lint_and_then(self.cx, MAP_ENTRY, self.span, - &format!("usage of `contains_key` followed by `insert` on a `{}`", self.ty), |diag| { - if self.sole_expr { - let mut app = Applicability::MachineApplicable; - let help = format!("{}.entry({}).or_insert({});", - snippet_with_applicability(self.cx, self.map.span, "map", &mut app), - snippet_with_applicability(self.cx, params[1].span, "..", &mut app), - snippet_with_applicability(self.cx, params[2].span, "..", &mut app)); - - diag.span_suggestion( - self.span, - "consider using", - help, - Applicability::MachineApplicable, // snippet - ); + if !self.can_use_entry { + return; + } + + match try_parse_insert(self.cx, expr) { + Some(insert_expr) if SpanlessEq::new(self.cx).eq_expr(self.map, insert_expr.map) => { + // Multiple inserts, inserts with a different key, and inserts from a macro can't use the entry api. + if self.is_map_used + || !SpanlessEq::new(self.cx).eq_expr(self.key, insert_expr.key) + || expr.span.ctxt() != self.ctxt + { + self.can_use_entry = false; + return; + } + + self.edits.push(Edit::Insertion(Insertion { + call: expr, + value: insert_expr.value, + })); + self.is_map_used = true; + self.allow_insert_closure &= self.in_tail_pos; + + // The value doesn't affect whether there is only a single insert expression. + let is_single_insert = self.is_single_insert; + self.visit_non_tail_expr(insert_expr.value); + self.is_single_insert = is_single_insert; + }, + _ if SpanlessEq::new(self.cx).eq_expr(self.map, expr) => { + self.is_map_used = true; + }, + _ => match expr.kind { + ExprKind::If(cond_expr, then_expr, Some(else_expr)) => { + self.is_single_insert = false; + self.visit_non_tail_expr(cond_expr); + // Each branch may contain it's own insert expression. + let mut is_map_used = self.visit_cond_arm(then_expr); + is_map_used |= self.visit_cond_arm(else_expr); + self.is_map_used = is_map_used; + }, + ExprKind::Match(scrutinee_expr, arms, _) => { + self.is_single_insert = false; + self.visit_non_tail_expr(scrutinee_expr); + // Each branch may contain it's own insert expression. + let mut is_map_used = self.is_map_used; + for arm in arms { + if let Some(Guard::If(guard) | Guard::IfLet(_, guard)) = arm.guard { + self.visit_non_tail_expr(guard); + } + is_map_used |= self.visit_cond_arm(arm.body); } - else { - let help = format!("consider using `{}.entry({})`", - snippet(self.cx, self.map.span, "map"), - snippet(self.cx, params[1].span, "..")); - - diag.span_label( - self.span, - &help, - ); + self.is_map_used = is_map_used; + }, + ExprKind::Loop(block, ..) => { + self.loops.push(expr.hir_id); + self.is_single_insert = false; + self.allow_insert_closure &= !self.in_tail_pos; + // Don't allow insertions inside of a loop. + let edit_len = self.edits.len(); + self.visit_block(block); + if self.edits.len() != edit_len { + self.can_use_entry = false; } - }); - } + self.loops.pop(); + }, + ExprKind::Block(block, _) => self.visit_block(block), + ExprKind::InlineAsm(_) | ExprKind::LlvmInlineAsm(_) => { + self.can_use_entry = false; + }, + _ => { + self.allow_insert_closure &= !self.in_tail_pos; + self.allow_insert_closure &= can_move_expr_to_closure_no_visit(self.cx, expr, &self.loops); + // Sub expressions are no longer in the tail position. + self.is_single_insert = false; + self.in_tail_pos = false; + walk_expr(self, expr); + }, + }, } + } +} + +struct InsertSearchResults<'tcx> { + edits: Vec>, + allow_insert_closure: bool, + is_single_insert: bool, +} +impl InsertSearchResults<'tcx> { + fn as_single_insertion(&self) -> Option> { + self.is_single_insert.then(|| self.edits[0].as_insertion().unwrap()) + } - if !self.sole_expr { - walk_expr(self, expr); + fn snippet( + &self, + cx: &LateContext<'_>, + mut span: Span, + app: &mut Applicability, + write_wrapped: impl Fn(&mut String, Insertion<'_>, SyntaxContext, &mut Applicability), + ) -> String { + let ctxt = span.ctxt(); + let mut res = String::new(); + for insertion in self.edits.iter().filter_map(|e| e.as_insertion()) { + res.push_str(&snippet_with_applicability( + cx, + span.until(insertion.call.span), + "..", + app, + )); + if is_expr_used_or_unified(cx.tcx, insertion.call) { + write_wrapped(&mut res, insertion, ctxt, app); + } else { + let _ = write!( + res, + "e.insert({})", + snippet_with_context(cx, insertion.value.span, ctxt, "..", app).0 + ); + } + span = span.trim_start(insertion.call.span).unwrap_or(DUMMY_SP); } + res.push_str(&snippet_with_applicability(cx, span, "..", app)); + res } - fn nested_visit_map(&mut self) -> NestedVisitorMap { - NestedVisitorMap::None + + fn snippet_occupied(&self, cx: &LateContext<'_>, span: Span, app: &mut Applicability) -> (String, &'static str) { + ( + self.snippet(cx, span, app, |res, insertion, ctxt, app| { + // Insertion into a map would return `Some(&mut value)`, but the entry returns `&mut value` + let _ = write!( + res, + "Some(e.insert({}))", + snippet_with_context(cx, insertion.value.span, ctxt, "..", app).0 + ); + }), + "Occupied(mut e)", + ) + } + + fn snippet_vacant(&self, cx: &LateContext<'_>, span: Span, app: &mut Applicability) -> (String, &'static str) { + ( + self.snippet(cx, span, app, |res, insertion, ctxt, app| { + // Insertion into a map would return `None`, but the entry returns a mutable reference. + let _ = if is_expr_final_block_expr(cx.tcx, insertion.call) { + write!( + res, + "e.insert({});\n{}None", + snippet_with_context(cx, insertion.value.span, ctxt, "..", app).0, + snippet_indent(cx, insertion.call.span).as_deref().unwrap_or(""), + ) + } else { + write!( + res, + "{{ e.insert({}); None }}", + snippet_with_context(cx, insertion.value.span, ctxt, "..", app).0, + ) + }; + }), + "Vacant(e)", + ) + } + + fn snippet_closure(&self, cx: &LateContext<'_>, mut span: Span, app: &mut Applicability) -> String { + let ctxt = span.ctxt(); + let mut res = String::new(); + for edit in &self.edits { + match *edit { + Edit::Insertion(insertion) => { + // Cut out the value from `map.insert(key, value)` + res.push_str(&snippet_with_applicability( + cx, + span.until(insertion.call.span), + "..", + app, + )); + res.push_str(&snippet_with_context(cx, insertion.value.span, ctxt, "..", app).0); + span = span.trim_start(insertion.call.span).unwrap_or(DUMMY_SP); + }, + Edit::RemoveSemi(semi_span) => { + // Cut out the semicolon. This allows the value to be returned from the closure. + res.push_str(&snippet_with_applicability(cx, span.until(semi_span), "..", app)); + span = span.trim_start(semi_span).unwrap_or(DUMMY_SP); + }, + } + } + res.push_str(&snippet_with_applicability(cx, span, "..", app)); + res } } + +fn find_insert_calls( + cx: &LateContext<'tcx>, + contains_expr: &ContainsExpr<'tcx>, + expr: &'tcx Expr<'_>, +) -> Option> { + let mut s = InsertSearcher { + cx, + map: contains_expr.map, + key: contains_expr.key, + ctxt: expr.span.ctxt(), + edits: Vec::new(), + is_map_used: false, + allow_insert_closure: true, + can_use_entry: true, + in_tail_pos: true, + is_single_insert: true, + loops: Vec::new(), + }; + s.visit_expr(expr); + let allow_insert_closure = s.allow_insert_closure; + let is_single_insert = s.is_single_insert; + let edits = s.edits; + s.can_use_entry.then(|| InsertSearchResults { + edits, + allow_insert_closure, + is_single_insert, + }) +}