use crate::utils::SpanlessEq;
-use crate::utils::{get_item_name, match_type, paths, snippet, span_lint_and_then, walk_ptrs_ty};
+use crate::utils::{get_item_name, higher, match_type, paths, snippet, snippet_opt, span_lint_and_then, walk_ptrs_ty};
use if_chain::if_chain;
use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
use rustc::hir::*;
///
/// **Known problems:** Some false negatives, eg.:
/// ```rust
- /// let k = &key;
- /// if !m.contains_key(k) {
- /// m.insert(k.clone(), v);
+ /// # 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);
/// }
/// ```
///
/// **Example:**
/// ```rust
- /// if !m.contains_key(&k) {
- /// m.insert(k, v)
+ /// # use std::collections::HashMap;
+ /// # let mut map = HashMap::new();
+ /// # let k = 1;
+ /// # let v = 1;
+ /// if !map.contains_key(&k) {
+ /// map.insert(k, v);
/// }
/// ```
- /// can be rewritten as:
+ /// can both be rewritten as:
/// ```rust
- /// m.entry(k).or_insert(v);
+ /// # use std::collections::HashMap;
+ /// # let mut map = HashMap::new();
+ /// # let k = 1;
+ /// # let v = 1;
+ /// map.entry(k).or_insert(v);
/// ```
pub MAP_ENTRY,
perf,
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for HashMapPass {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
- if let ExprKind::If(ref check, ref then_block, ref else_block) = expr.node {
+ if let Some((ref check, ref then_block, ref else_block)) = higher::if_block(&expr) {
if let ExprKind::Unary(UnOp::UnNot, ref check) = check.node {
if let Some((ty, map, key)) = check_cond(cx, check) {
// in case of `if !m.contains_key(&k) { m.insert(k, v); }`
if_chain! {
if let ExprKind::MethodCall(ref path, _, ref params) = check.node;
if params.len() >= 2;
- if path.ident.name == "contains_key";
+ if path.ident.name == sym!(contains_key);
if let ExprKind::AddrOf(_, ref key) = params[1].node;
then {
let map = ¶ms[0];
None
}
-struct InsertVisitor<'a, 'tcx: 'a, 'b> {
+struct InsertVisitor<'a, 'tcx, 'b> {
cx: &'a LateContext<'a, 'tcx>,
span: Span,
ty: &'static str,
if_chain! {
if let ExprKind::MethodCall(ref path, _, ref params) = expr.node;
if params.len() == 3;
- if path.ident.name == "insert";
+ 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), |db| {