use crate::utils::paths;
use crate::utils::{
- in_macro, match_trait_method, match_type, remove_blocks, snippet_with_applicability, 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 rustc::hir;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::ty;
-use rustc::{declare_tool_lint, lint_array};
+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_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
+ hir::BindingAnnotation::Unannotated, .., name, None
) = inner.node {
if ident_eq(name, closure_expr) {
- lint(cx, e.span, args[0].span);
+ // 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) => {
+ 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);
+ lint(cx, e.span, args[0].span, is_option);
}
},
hir::ExprKind::MethodCall(ref method, _, ref obj) => {
&& match_trait_method(cx, closure_expr, &paths::CLONE_TRAIT) {
let obj_ty = cx.tables.expr_ty(&obj[0]);
- if let ty::Ref(..) = obj_ty.sty {
- lint(cx, e.span, args[0].span);
+ 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) {
+fn lint(cx: &LateContext<'_, '_>, replace: Span, root: Span, copied: bool) {
let mut applicability = Applicability::MachineApplicable;
- 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,
- )
+ 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,
+ )
+ }
}