| use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg}; |
| use clippy_utils::source::{reindent_multiline, snippet_indent, snippet_with_applicability, snippet_with_context}; |
| use clippy_utils::ty::is_copy; |
| use clippy_utils::visitors::for_each_expr; |
| use clippy_utils::{ |
| SpanlessEq, can_move_expr_to_closure_no_visit, higher, is_expr_final_block_expr, is_expr_used_or_unified, |
| peel_hir_expr_while, |
| }; |
| use core::fmt::{self, Write}; |
| use rustc_errors::Applicability; |
| use rustc_hir::hir_id::HirIdSet; |
| use rustc_hir::intravisit::{Visitor, walk_body, walk_expr}; |
| use rustc_hir::{Block, Expr, ExprKind, HirId, Pat, Stmt, StmtKind, UnOp}; |
| use rustc_lint::{LateContext, LateLintPass}; |
| use rustc_session::declare_lint_pass; |
| use rustc_span::{DUMMY_SP, Span, SyntaxContext, sym}; |
| use std::ops::ControlFlow; |
| |
| declare_clippy_lint! { |
| /// ### What it does |
| /// Checks for usage of `contains_key` + `insert` on `HashMap` |
| /// or `BTreeMap`. |
| /// |
| /// ### Why is this bad? |
| /// Using `entry` is more efficient. |
| /// |
| /// ### Known problems |
| /// The suggestion may have type inference errors in some cases. e.g. |
| /// ```no_run |
| /// let mut map = std::collections::HashMap::new(); |
| /// let _ = if !map.contains_key(&0) { |
| /// map.insert(0, 0) |
| /// } else { |
| /// None |
| /// }; |
| /// ``` |
| /// |
| /// ### Example |
| /// ```no_run |
| /// # use std::collections::HashMap; |
| /// # let mut map = HashMap::new(); |
| /// # let k = 1; |
| /// # let v = 1; |
| /// if !map.contains_key(&k) { |
| /// map.insert(k, v); |
| /// } |
| /// ``` |
| /// Use instead: |
| /// ```no_run |
| /// # use std::collections::HashMap; |
| /// # let mut map = HashMap::new(); |
| /// # let k = 1; |
| /// # let v = 1; |
| /// map.entry(k).or_insert(v); |
| /// ``` |
| #[clippy::version = "pre 1.29.0"] |
| pub MAP_ENTRY, |
| perf, |
| "use of `contains_key` followed by `insert` on a `HashMap` or `BTreeMap`" |
| } |
| |
| declare_lint_pass!(HashMapPass => [MAP_ENTRY]); |
| |
| impl<'tcx> LateLintPass<'tcx> for HashMapPass { |
| #[expect(clippy::too_many_lines)] |
| fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { |
| if expr.span.from_expansion() { |
| return; |
| } |
| |
| let Some(higher::If { |
| cond: cond_expr, |
| then: then_expr, |
| r#else: else_expr, |
| }) = higher::If::hir(expr) |
| else { |
| return; |
| }; |
| |
| let Some((map_ty, contains_expr)) = try_parse_contains(cx, cond_expr) else { |
| return; |
| }; |
| |
| let Some(then_search) = find_insert_calls(cx, &contains_expr, then_expr) else { |
| return; |
| }; |
| |
| let lint_msg = format!("usage of `contains_key` followed by `insert` on a `{}`", map_ty.name()); |
| 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 Some(else_search) = find_insert_calls(cx, &contains_expr, else_expr) else { |
| return; |
| }; |
| |
| if then_search.edits.is_empty() && else_search.edits.is_empty() { |
| // No insertions |
| return; |
| } else if then_search.is_key_used_and_no_copy || else_search.is_key_used_and_no_copy { |
| // If there are other uses of the key, and the key is not copy, |
| // we cannot perform a fix automatically, but continue to emit a lint. |
| None |
| } 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), |
| ), |
| }; |
| Some(format!( |
| "if let {}::{entry_kind} = {map_str}.entry({key_str}) {then_str} else {else_str}", |
| map_ty.entry_path(), |
| )) |
| } 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(""); |
| Some(format!( |
| "match {map_str}.entry({key_str}) {{\n{indent_str} {entry}::{then_entry} => {}\n\ |
| {indent_str} {entry}::{else_entry} => {}\n{indent_str}}}", |
| reindent_multiline(&then_str, true, Some(4 + indent_str.len())), |
| reindent_multiline(&else_str, true, Some(4 + indent_str.len())), |
| entry = map_ty.entry_path(), |
| )) |
| } |
| } 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) |
| }; |
| Some(format!( |
| "if let {}::{entry_kind} = {map_str}.entry({key_str}) {body_str}", |
| map_ty.entry_path(), |
| )) |
| } 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() { |
| Some(format!("{map_str}.entry({key_str}).or_insert_with(|| {value_str});")) |
| } else { |
| Some(format!("{map_str}.entry({key_str}).or_insert({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 { |
| let block_str = then_search.snippet_closure(cx, then_expr.span, &mut app); |
| if contains_expr.negated { |
| Some(format!("{map_str}.entry({key_str}).or_insert_with(|| {block_str});")) |
| } else { |
| // TODO: suggest using `if let Some(v) = map.get_mut(k) { .. }` here. |
| // This would need to be a different lint. |
| return; |
| } |
| } |
| }; |
| |
| if let Some(sugg) = sugg { |
| span_lint_and_sugg(cx, MAP_ENTRY, expr.span, lint_msg, "try", sugg, app); |
| } else { |
| span_lint_and_help( |
| cx, |
| MAP_ENTRY, |
| expr.span, |
| lint_msg, |
| None, |
| format!( |
| "consider using the `Entry` API: https://doc.rust-lang.org/std/collections/struct.{}.html#entry-api", |
| map_ty.name() |
| ), |
| ); |
| } |
| } |
| } |
| |
| #[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", |
| } |
| } |
| } |
| |
| /// Details on an expression checking whether a map contains a key. |
| /// |
| /// For instance, with the following: |
| /// ```ignore |
| /// !!!self.the_map.contains_key("the_key") |
| /// ``` |
| /// |
| /// - `negated` will be set to `true` (the 3 `!` negate the condition) |
| /// - `map` will be the `self.the_map` expression |
| /// - `key` will be the `"the_key"` expression |
| struct ContainsExpr<'tcx> { |
| /// Whether the check for `contains_key` was negated. |
| negated: bool, |
| /// The map on which the check is performed. |
| map: &'tcx Expr<'tcx>, |
| /// The key that is checked to be contained. |
| key: &'tcx Expr<'tcx>, |
| /// The context of the whole condition expression. |
| call_ctxt: SyntaxContext, |
| } |
| |
| /// Inspect the given expression and return details about the `contains_key` check. |
| /// |
| /// If the given expression is not a `contains_key` check against a `BTreeMap` or a `HashMap`, |
| /// return `None`. |
| fn try_parse_contains<'tcx>(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, |
| }); |
| |
| if let ExprKind::MethodCall(_, map, [arg], _) = expr.kind |
| && let Expr { |
| kind: ExprKind::AddrOf(_, _, key), |
| span: key_span, |
| .. |
| } = arg |
| && key_span.eq_ctxt(expr.span) |
| { |
| let id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?; |
| let expr = ContainsExpr { |
| negated, |
| map, |
| key, |
| call_ctxt: expr.span.ctxt(), |
| }; |
| match cx.tcx.get_diagnostic_name(id) { |
| Some(sym::btreemap_contains_key) => Some((MapType::BTree, expr)), |
| Some(sym::hashmap_contains_key) => Some((MapType::Hash, expr)), |
| _ => None, |
| } |
| } else { |
| None |
| } |
| } |
| |
| /// Details on an expression inserting a key into a map. |
| /// |
| /// For instance, on the following: |
| /// ```ignore |
| /// self.the_map.insert("the_key", 3 + 4); |
| /// ``` |
| /// |
| /// - `map` will be the `self.the_map` expression |
| /// - `key` will be the `"the_key"` expression |
| /// - `value` will be the `3 + 4` expression |
| struct InsertExpr<'tcx> { |
| /// The map into which the insertion is performed. |
| map: &'tcx Expr<'tcx>, |
| /// The key at which to insert. |
| key: &'tcx Expr<'tcx>, |
| /// The value to insert. |
| value: &'tcx Expr<'tcx>, |
| } |
| |
| /// Inspect the given expression and return details about the `insert` call. |
| /// |
| /// If the given expression is not an `insert` call into a `BTreeMap` or a `HashMap`, return `None`. |
| fn try_parse_insert<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<InsertExpr<'tcx>> { |
| if let ExprKind::MethodCall(_, map, [key, value], _) = expr.kind { |
| let id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?; |
| if let Some(insert) = cx.tcx.get_diagnostic_name(id) |
| && matches!(insert, sym::btreemap_insert | sym::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<'tcx> Edit<'tcx> { |
| fn as_insertion(self) -> Option<Insertion<'tcx>> { |
| if let Self::Insertion(i) = self { Some(i) } else { None } |
| } |
| } |
| #[derive(Clone, Copy, Debug)] |
| struct Insertion<'tcx> { |
| call: &'tcx Expr<'tcx>, |
| value: &'tcx Expr<'tcx>, |
| } |
| |
| /// This visitor needs to do 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. |
| #[expect(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, |
| /// The spanless equality utility used to compare expressions. |
| spanless_eq: SpanlessEq<'cx, 'tcx>, |
| /// 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, |
| /// If the visitor has seen the key being used. |
| is_key_used: bool, |
| /// The locations where changes need to be made for the suggestion. |
| edits: Vec<Edit<'tcx>>, |
| /// A stack of loops the visitor is currently in. |
| loops: Vec<HirId>, |
| /// Local variables created in the expression. These don't need to be captured. |
| locals: HirIdSet, |
| } |
| 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 |
| } |
| |
| /// Visit 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; |
| } |
| |
| /// Visit the key and value expression of an insert expression. |
| /// There may not be uses of the map in either of those two either. |
| fn visit_insert_expr_arguments(&mut self, e: &InsertExpr<'tcx>) { |
| let in_tail_pos = self.in_tail_pos; |
| let allow_insert_closure = self.allow_insert_closure; |
| let is_single_insert = self.is_single_insert; |
| walk_expr(self, e.key); |
| walk_expr(self, e.value); |
| self.in_tail_pos = in_tail_pos; |
| self.allow_insert_closure = allow_insert_closure; |
| self.is_single_insert = is_single_insert; |
| } |
| } |
| impl<'tcx> Visitor<'tcx> for InsertSearcher<'_, 'tcx> { |
| 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::Let(l) => { |
| self.visit_pat(l.pat); |
| if let Some(e) = l.init { |
| self.allow_insert_closure &= !self.in_tail_pos; |
| self.in_tail_pos = false; |
| self.is_single_insert = false; |
| self.visit_expr(e); |
| } |
| if let Some(els) = &l.els { |
| self.visit_block(els); |
| } |
| }, |
| StmtKind::Item(_) => { |
| self.allow_insert_closure &= !self.in_tail_pos; |
| self.is_single_insert = false; |
| }, |
| } |
| } |
| |
| 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 !self.can_use_entry { |
| return; |
| } |
| |
| match try_parse_insert(self.cx, expr) { |
| Some(insert_expr) if self.spanless_eq.eq_expr(self.map, insert_expr.map) => { |
| self.visit_insert_expr_arguments(&insert_expr); |
| // Multiple inserts, inserts with a different key, and inserts from a macro can't use the entry api. |
| if self.is_map_used |
| || !self.spanless_eq.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 is_any_expr_in_map_used(self.cx, &mut self.spanless_eq, self.map, expr) => { |
| self.is_map_used = true; |
| }, |
| _ if self.spanless_eq.eq_expr(self.key, expr) => { |
| self.is_key_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 { |
| self.visit_pat(arm.pat); |
| if let Some(guard) = arm.guard { |
| self.visit_non_tail_expr(guard); |
| } |
| is_map_used |= self.visit_cond_arm(arm.body); |
| } |
| 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(_) => { |
| self.can_use_entry = false; |
| }, |
| ExprKind::Closure(closure) => walk_body(self, self.cx.tcx.hir_body(closure.body)), |
| _ => { |
| self.allow_insert_closure &= !self.in_tail_pos; |
| self.allow_insert_closure &= |
| can_move_expr_to_closure_no_visit(self.cx, expr, &self.loops, &self.locals); |
| // Sub expressions are no longer in the tail position. |
| self.is_single_insert = false; |
| self.in_tail_pos = false; |
| walk_expr(self, expr); |
| }, |
| }, |
| } |
| } |
| |
| fn visit_pat(&mut self, p: &'tcx Pat<'tcx>) { |
| p.each_binding_or_first(&mut |_, id, _, _| { |
| self.locals.insert(id); |
| }); |
| } |
| } |
| |
| /// Check if the given expression is used for each sub-expression in the given map. |
| /// For example, in map `a.b.c.my_map`, The expression `a.b.c.my_map`, `a.b.c`, `a.b`, and `a` are |
| /// all checked. |
| fn is_any_expr_in_map_used<'tcx>( |
| cx: &LateContext<'tcx>, |
| spanless_eq: &mut SpanlessEq<'_, 'tcx>, |
| map: &'tcx Expr<'tcx>, |
| expr: &'tcx Expr<'tcx>, |
| ) -> bool { |
| for_each_expr(cx, map, |e| { |
| if spanless_eq.eq_expr(e, expr) { |
| return ControlFlow::Break(()); |
| } |
| ControlFlow::Continue(()) |
| }) |
| .is_some() |
| } |
| |
| struct InsertSearchResults<'tcx> { |
| edits: Vec<Edit<'tcx>>, |
| allow_insert_closure: bool, |
| is_single_insert: bool, |
| is_key_used_and_no_copy: bool, |
| } |
| impl<'tcx> InsertSearchResults<'tcx> { |
| fn as_single_insertion(&self) -> Option<Insertion<'tcx>> { |
| self.is_single_insert.then(|| self.edits[0].as_insertion().unwrap()) |
| } |
| |
| 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 _: fmt::Result = 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 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 _: fmt::Result = 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 _: fmt::Result = 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<'tcx>( |
| cx: &LateContext<'tcx>, |
| contains_expr: &ContainsExpr<'tcx>, |
| expr: &'tcx Expr<'_>, |
| ) -> Option<InsertSearchResults<'tcx>> { |
| let mut s = InsertSearcher { |
| cx, |
| map: contains_expr.map, |
| key: contains_expr.key, |
| ctxt: expr.span.ctxt(), |
| spanless_eq: SpanlessEq::new(cx), |
| allow_insert_closure: true, |
| can_use_entry: true, |
| in_tail_pos: true, |
| is_single_insert: true, |
| is_map_used: false, |
| is_key_used: false, |
| edits: Vec::new(), |
| loops: Vec::new(), |
| locals: HirIdSet::default(), |
| }; |
| s.visit_expr(expr); |
| let allow_insert_closure = s.allow_insert_closure; |
| let is_single_insert = s.is_single_insert; |
| let is_key_used_and_no_copy = s.is_key_used && !is_copy(cx, cx.typeck_results().expr_ty(contains_expr.key)); |
| let edits = s.edits; |
| s.can_use_entry.then_some(InsertSearchResults { |
| edits, |
| allow_insert_closure, |
| is_single_insert, |
| is_key_used_and_no_copy, |
| }) |
| } |
