-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-
-use crate::rustc::hir;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::syntax::source_map::Span;
use crate::utils::paths;
use crate::utils::{
- in_macro, match_trait_method, match_type,
- remove_blocks, snippet,
- span_lint_and_sugg,
+ in_macro, is_copy, match_trait_method, match_type, remove_blocks, snippet_with_applicability, span_lint_and_sugg,
};
use if_chain::if_chain;
-use crate::syntax::ast::Ident;
+use rustc::hir;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::ty;
+use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_errors::Applicability;
+use syntax::ast::Ident;
+use syntax::source_map::Span;
-#[derive(Clone)]
-pub struct Pass;
-
-/// **What it does:** Checks for usage of `iterator.map(|x| x.clone())` and suggests
-/// `iterator.cloned()` instead
-///
-/// **Why is this bad?** Readability, this can be written more concisely
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-///
-/// ```rust
-/// let x = vec![42, 43];
-/// let y = x.iter();
-/// let z = y.map(|i| *i);
-/// ```
-///
-/// The correct use would be:
-///
-/// ```rust
-/// let x = vec![42, 43];
-/// let y = x.iter();
-/// let z = y.cloned();
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `iterator.map(|x| x.clone())` and suggests
+ /// `iterator.cloned()` instead
+ ///
+ /// **Why is this bad?** Readability, this can be written more concisely
+ ///
+ /// **Known problems:** None
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// let x = vec![42, 43];
+ /// let y = x.iter();
+ /// let z = y.map(|i| *i);
+ /// ```
+ ///
+ /// The correct use would be:
+ ///
+ /// ```rust
+ /// let x = vec![42, 43];
+ /// let y = x.iter();
+ /// let z = y.cloned();
+ /// ```
pub MAP_CLONE,
style,
"using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types"
}
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(MAP_CLONE)
- }
-}
+declare_lint_pass!(MapClone => [MAP_CLONE]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MapClone {
fn check_expr(&mut self, cx: &LateContext<'_, '_>, e: &hir::Expr) {
if in_macro(e.span) {
return;
if args.len() == 2;
if method.ident.as_str() == "map";
let ty = cx.tables.expr_ty(&args[0]);
- if match_type(cx, ty, &paths::OPTION) || match_trait_method(cx, e, &paths::ITERATOR);
+ let is_option = match_type(cx, ty, &paths::OPTION);
+ if is_option || match_trait_method(cx, e, &paths::ITERATOR);
if let hir::ExprKind::Closure(_, _, body_id, _, _) = args[1].node;
- let closure_body = cx.tcx.hir.body(body_id);
+ let closure_body = cx.tcx.hir().body(body_id);
let closure_expr = remove_blocks(&closure_body.value);
then {
match closure_body.arguments[0].pat.node {
- hir::PatKind::Ref(ref inner, _) => if let hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, name, None) = inner.node {
- lint(cx, e.span, args[0].span, name, closure_expr);
+ hir::PatKind::Ref(ref inner, _) => if let hir::PatKind::Binding(
+ hir::BindingAnnotation::Unannotated, .., name, None
+ ) = inner.node {
+ if ident_eq(name, closure_expr) {
+ // FIXME When Iterator::copied() stabilizes we can remove is_option
+ // from here and the other lint() calls
+ lint(cx, e.span, args[0].span, is_option);
+ }
},
- hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, name, None) => match closure_expr.node {
- hir::ExprKind::Unary(hir::UnOp::UnDeref, ref inner) => lint(cx, e.span, args[0].span, name, inner),
- hir::ExprKind::MethodCall(ref method, _, ref obj) => if method.ident.as_str() == "clone" && match_trait_method(cx, closure_expr, &paths::CLONE_TRAIT) {
- lint(cx, e.span, args[0].span, name, &obj[0]);
+ hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, .., name, None) => {
+ match closure_expr.node {
+ hir::ExprKind::Unary(hir::UnOp::UnDeref, ref inner) => {
+ if ident_eq(name, inner) && !cx.tables.expr_ty(inner).is_box() {
+ lint(cx, e.span, args[0].span, is_option);
+ }
+ },
+ hir::ExprKind::MethodCall(ref method, _, ref obj) => {
+ if ident_eq(name, &obj[0]) && method.ident.as_str() == "clone"
+ && match_trait_method(cx, closure_expr, &paths::CLONE_TRAIT) {
+
+ let obj_ty = cx.tables.expr_ty(&obj[0]);
+ if let ty::Ref(_, ty, _) = obj_ty.sty {
+ let copy = is_copy(cx, ty);
+ lint(cx, e.span, args[0].span, is_option && copy);
+ } else {
+ lint_needless_cloning(cx, e.span, args[0].span);
+ }
+ }
+ },
+ _ => {},
}
- _ => {},
},
_ => {},
}
}
}
-fn lint(cx: &LateContext<'_, '_>, replace: Span, root: Span, name: Ident, path: &hir::Expr) {
+fn ident_eq(name: Ident, path: &hir::Expr) -> bool {
if let hir::ExprKind::Path(hir::QPath::Resolved(None, ref path)) = path.node {
- if path.segments.len() == 1 && path.segments[0].ident == name {
- span_lint_and_sugg(
- cx,
- MAP_CLONE,
- replace,
- "You are using an explicit closure for cloning elements",
- "Consider calling the dedicated `cloned` method",
- format!("{}.cloned()", snippet(cx, root, "..")),
- )
- }
+ path.segments.len() == 1 && path.segments[0].ident == name
+ } else {
+ false
+ }
+}
+
+fn lint_needless_cloning(cx: &LateContext<'_, '_>, root: Span, receiver: Span) {
+ span_lint_and_sugg(
+ cx,
+ MAP_CLONE,
+ root.trim_start(receiver).unwrap(),
+ "You are needlessly cloning iterator elements",
+ "Remove the map call",
+ String::new(),
+ Applicability::MachineApplicable,
+ )
+}
+
+fn lint(cx: &LateContext<'_, '_>, replace: Span, root: Span, copied: bool) {
+ let mut applicability = Applicability::MachineApplicable;
+ if copied {
+ span_lint_and_sugg(
+ cx,
+ MAP_CLONE,
+ replace,
+ "You are using an explicit closure for copying elements",
+ "Consider calling the dedicated `copied` method",
+ format!(
+ "{}.copied()",
+ snippet_with_applicability(cx, root, "..", &mut applicability)
+ ),
+ applicability,
+ )
+ } else {
+ span_lint_and_sugg(
+ cx,
+ MAP_CLONE,
+ replace,
+ "You are using an explicit closure for cloning elements",
+ "Consider calling the dedicated `cloned` method",
+ format!(
+ "{}.cloned()",
+ snippet_with_applicability(cx, root, "..", &mut applicability)
+ ),
+ applicability,
+ )
}
}
projects / rust.git / blobdiff