X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fentry.rs;h=4403ef45ca339aa56ebd224792749fc29e85bdc1;hb=6d1225981177587fbb68d9c4902c770c3dbaafb0;hp=46ef16ddc7394e052074068ad2e4423ac5ddb516;hpb=b87ab5ccf2d30442cba8d0de08edb0f86a33ca58;p=rust.git diff --git a/clippy_lints/src/entry.rs b/clippy_lints/src/entry.rs index 46ef16ddc73..4403ef45ca3 100644 --- a/clippy_lints/src/entry.rs +++ b/clippy_lints/src/entry.rs @@ -1,59 +1,72 @@ -use rustc::hir::*; +use crate::utils::SpanlessEq; +use crate::utils::{get_item_name, higher, 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 rustc::declare_lint_pass; use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor}; +use rustc::hir::*; use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; -use rustc::{declare_lint, lint_array}; -use if_chain::if_chain; +use rustc_errors::Applicability; +use rustc_session::declare_tool_lint; use syntax::source_map::Span; -use crate::utils::SpanlessEq; -use crate::utils::{get_item_name, match_type, paths, snippet, span_lint_and_then, walk_ptrs_ty}; -/// **What it does:** Checks for uses of `contains_key` + `insert` on `HashMap` -/// or `BTreeMap`. -/// -/// **Why is this bad?** Using `entry` is more efficient. -/// -/// **Known problems:** Some false negatives, eg.: -/// ```rust -/// let k = &key; -/// if !m.contains_key(k) { m.insert(k.clone(), v); } -/// ``` -/// -/// **Example:** -/// ```rust -/// if !m.contains_key(&k) { m.insert(k, v) } -/// ``` -/// can be rewritten as: -/// ```rust -/// m.entry(k).or_insert(v); -/// ``` declare_clippy_lint! { + /// **What it does:** Checks for uses of `contains_key` + `insert` on `HashMap` + /// or `BTreeMap`. + /// + /// **Why is this bad?** Using `entry` is more efficient. + /// + /// **Known problems:** Some false negatives, eg.: + /// ```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); + /// } + /// ``` + /// + /// **Example:** + /// ```rust + /// # 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 both be rewritten as: + /// ```rust + /// # 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, "use of `contains_key` followed by `insert` on a `HashMap` or `BTreeMap`" } -#[derive(Copy, Clone)] -pub struct HashMapLint; +declare_lint_pass!(HashMapPass => [MAP_ENTRY]); -impl LintPass for HashMapLint { - fn get_lints(&self) -> LintArray { - lint_array!(MAP_ENTRY) - } -} - -impl<'a, 'tcx> LateLintPass<'a, 'tcx> for HashMapLint { +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 ExprKind::Unary(UnOp::UnNot, ref check) = check.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.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.node { - (then_block.expr.is_some() as usize) + then_block.stmts.len() == 1 - } else { - true - } + 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 { @@ -90,10 +103,10 @@ fn check_cond<'a, 'tcx, 'b>( check: &'b Expr, ) -> Option<(&'static str, &'b Expr, &'b Expr)> { if_chain! { - if let ExprKind::MethodCall(ref path, _, ref params) = check.node; + if let ExprKind::MethodCall(ref path, _, ref params) = check.kind; if params.len() >= 2; - if path.ident.name == "contains_key"; - if let ExprKind::AddrOf(_, ref key) = params[1].node; + 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)); @@ -113,7 +126,7 @@ fn check_cond<'a, 'tcx, 'b>( None } -struct InsertVisitor<'a, 'tcx: 'a, 'b> { +struct InsertVisitor<'a, 'tcx, 'b> { cx: &'a LateContext<'a, 'tcx>, span: Span, ty: &'static str, @@ -125,28 +138,38 @@ struct InsertVisitor<'a, 'tcx: 'a, 'b> { impl<'a, 'tcx, 'b> Visitor<'tcx> for InsertVisitor<'a, 'tcx, 'b> { fn visit_expr(&mut self, expr: &'tcx Expr) { if_chain! { - if let ExprKind::MethodCall(ref path, _, ref params) = expr.node; + if let ExprKind::MethodCall(ref path, _, ref params) = expr.kind; 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| { if self.sole_expr { - let help = format!("{}.entry({}).or_insert({})", - snippet(self.cx, self.map.span, "map"), - snippet(self.cx, params[1].span, ".."), - snippet(self.cx, params[2].span, "..")); + 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)); - db.span_suggestion(self.span, "consider using", help); + db.span_suggestion( + self.span, + "consider using", + help, + Applicability::MachineApplicable, // snippet + ); } else { - let help = format!("{}.entry({})", + let help = format!("consider using `{}.entry({})`", snippet(self.cx, self.map.span, "map"), snippet(self.cx, params[1].span, "..")); - db.span_suggestion(self.span, "consider using", help); + db.span_label( + self.span, + &help, + ); } }); }