2018-11-27 20:14:15 +00:00
|
|
|
use crate::utils::{
|
2021-03-12 17:09:19 +00:00
|
|
|
is_copy, is_trait_method, is_type_diagnostic_item, remove_blocks, snippet_with_applicability, span_lint_and_sugg,
|
2018-11-27 20:14:15 +00:00
|
|
|
};
|
2018-10-02 13:13:43 +00:00
|
|
|
use if_chain::if_chain;
|
2018-12-29 15:04:45 +00:00
|
|
|
use rustc_errors::Applicability;
|
2020-01-06 16:39:50 +00:00
|
|
|
use rustc_hir as hir;
|
2020-01-12 06:08:41 +00:00
|
|
|
use rustc_lint::{LateContext, LateLintPass};
|
2020-04-25 20:49:06 +00:00
|
|
|
use rustc_middle::mir::Mutability;
|
2020-03-30 09:02:14 +00:00
|
|
|
use rustc_middle::ty;
|
2020-11-23 12:51:04 +00:00
|
|
|
use rustc_middle::ty::adjustment::Adjust;
|
2020-01-11 11:37:08 +00:00
|
|
|
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
2020-05-08 11:57:01 +00:00
|
|
|
use rustc_span::symbol::Ident;
|
2020-11-05 13:29:48 +00:00
|
|
|
use rustc_span::{sym, Span};
|
2018-10-02 13:13:43 +00:00
|
|
|
|
|
|
|
declare_clippy_lint! {
|
2020-11-23 12:51:04 +00:00
|
|
|
/// **What it does:** Checks for usage of `map(|x| x.clone())` or
|
|
|
|
/// dereferencing closures for `Copy` types, on `Iterator` or `Option`,
|
|
|
|
/// and suggests `cloned()` or `copied()` instead
|
2019-03-05 16:50:33 +00:00
|
|
|
///
|
|
|
|
/// **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();
|
|
|
|
/// ```
|
2018-10-02 13:13:43 +00:00
|
|
|
pub MAP_CLONE,
|
|
|
|
style,
|
|
|
|
"using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types"
|
|
|
|
}
|
|
|
|
|
2019-04-08 20:43:55 +00:00
|
|
|
declare_lint_pass!(MapClone => [MAP_CLONE]);
|
2018-10-02 13:13:43 +00:00
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
impl<'tcx> LateLintPass<'tcx> for MapClone {
|
|
|
|
fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) {
|
2019-08-19 16:30:32 +00:00
|
|
|
if e.span.from_expansion() {
|
2018-10-02 13:13:43 +00:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
if_chain! {
|
2020-06-09 21:44:04 +00:00
|
|
|
if let hir::ExprKind::MethodCall(ref method, _, ref args, _) = e.kind;
|
2018-10-02 13:13:43 +00:00
|
|
|
if args.len() == 2;
|
2021-01-15 09:56:44 +00:00
|
|
|
if method.ident.name == sym::map;
|
2020-07-17 08:47:04 +00:00
|
|
|
let ty = cx.typeck_results().expr_ty(&args[0]);
|
2021-03-12 17:09:19 +00:00
|
|
|
if is_type_diagnostic_item(cx, ty, sym::option_type) || is_trait_method(cx, e, sym::Iterator);
|
2019-09-27 15:16:06 +00:00
|
|
|
if let hir::ExprKind::Closure(_, _, body_id, _, _) = args[1].kind;
|
2018-12-08 00:56:03 +00:00
|
|
|
let closure_body = cx.tcx.hir().body(body_id);
|
2018-10-02 13:13:43 +00:00
|
|
|
let closure_expr = remove_blocks(&closure_body.value);
|
|
|
|
then {
|
2019-09-27 15:16:06 +00:00
|
|
|
match closure_body.params[0].pat.kind {
|
2020-04-25 20:49:06 +00:00
|
|
|
hir::PatKind::Ref(ref inner, hir::Mutability::Not) => if let hir::PatKind::Binding(
|
2019-02-03 07:12:07 +00:00
|
|
|
hir::BindingAnnotation::Unannotated, .., name, None
|
2019-09-27 15:16:06 +00:00
|
|
|
) = inner.kind {
|
2019-01-15 06:09:47 +00:00
|
|
|
if ident_eq(name, closure_expr) {
|
2019-04-28 18:14:39 +00:00
|
|
|
lint(cx, e.span, args[0].span, true);
|
2019-01-15 06:09:47 +00:00
|
|
|
}
|
2018-10-02 13:13:43 +00:00
|
|
|
},
|
2019-02-03 07:12:07 +00:00
|
|
|
hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, .., name, None) => {
|
2019-09-27 15:16:06 +00:00
|
|
|
match closure_expr.kind {
|
2021-02-09 08:15:53 +00:00
|
|
|
hir::ExprKind::Unary(hir::UnOp::Deref, ref inner) => {
|
2019-12-22 09:26:51 +00:00
|
|
|
if ident_eq(name, inner) {
|
2020-08-03 22:18:29 +00:00
|
|
|
if let ty::Ref(.., Mutability::Not) = cx.typeck_results().expr_ty(inner).kind() {
|
2019-12-22 09:26:51 +00:00
|
|
|
lint(cx, e.span, args[0].span, true);
|
|
|
|
}
|
2018-11-27 20:14:15 +00:00
|
|
|
}
|
|
|
|
},
|
2020-11-23 12:51:04 +00:00
|
|
|
hir::ExprKind::MethodCall(ref method, _, [obj], _) => if_chain! {
|
|
|
|
if ident_eq(name, obj) && method.ident.name == sym::clone;
|
2021-03-02 03:55:26 +00:00
|
|
|
if let Some(fn_id) = cx.typeck_results().type_dependent_def_id(closure_expr.hir_id);
|
|
|
|
if let Some(trait_id) = cx.tcx.trait_of_item(fn_id);
|
2021-03-08 16:08:52 +00:00
|
|
|
if cx.tcx.lang_items().clone_trait().map_or(false, |id| id == trait_id);
|
2020-11-23 12:51:04 +00:00
|
|
|
// no autoderefs
|
|
|
|
if !cx.typeck_results().expr_adjustments(obj).iter()
|
|
|
|
.any(|a| matches!(a.kind, Adjust::Deref(Some(..))));
|
|
|
|
then {
|
|
|
|
let obj_ty = cx.typeck_results().expr_ty(obj);
|
|
|
|
if let ty::Ref(_, ty, mutability) = obj_ty.kind() {
|
|
|
|
if matches!(mutability, Mutability::Not) {
|
|
|
|
let copy = is_copy(cx, ty);
|
|
|
|
lint(cx, e.span, args[0].span, copy);
|
|
|
|
}
|
2019-01-15 06:09:47 +00:00
|
|
|
} else {
|
|
|
|
lint_needless_cloning(cx, e.span, args[0].span);
|
|
|
|
}
|
2018-11-27 20:14:15 +00:00
|
|
|
}
|
|
|
|
},
|
|
|
|
_ => {},
|
2018-10-02 13:13:43 +00:00
|
|
|
}
|
|
|
|
},
|
|
|
|
_ => {},
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
fn ident_eq(name: Ident, path: &hir::Expr<'_>) -> bool {
|
2019-09-27 15:16:06 +00:00
|
|
|
if let hir::ExprKind::Path(hir::QPath::Resolved(None, ref path)) = path.kind {
|
2019-01-15 06:09:47 +00:00
|
|
|
path.segments.len() == 1 && path.segments[0].ident == name
|
|
|
|
} else {
|
|
|
|
false
|
2018-10-02 13:13:43 +00:00
|
|
|
}
|
2018-10-02 13:18:56 +00:00
|
|
|
}
|
2019-01-15 06:09:47 +00:00
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
fn lint_needless_cloning(cx: &LateContext<'_>, root: Span, receiver: Span) {
|
2019-01-15 06:09:47 +00:00
|
|
|
span_lint_and_sugg(
|
|
|
|
cx,
|
|
|
|
MAP_CLONE,
|
|
|
|
root.trim_start(receiver).unwrap(),
|
2020-08-28 14:10:16 +00:00
|
|
|
"you are needlessly cloning iterator elements",
|
|
|
|
"remove the `map` call",
|
2019-01-15 06:09:47 +00:00
|
|
|
String::new(),
|
|
|
|
Applicability::MachineApplicable,
|
|
|
|
)
|
|
|
|
}
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
fn lint(cx: &LateContext<'_>, replace: Span, root: Span, copied: bool) {
|
2019-01-15 06:09:47 +00:00
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
2019-04-15 21:32:39 +00:00
|
|
|
if copied {
|
|
|
|
span_lint_and_sugg(
|
|
|
|
cx,
|
|
|
|
MAP_CLONE,
|
|
|
|
replace,
|
2020-08-28 14:10:16 +00:00
|
|
|
"you are using an explicit closure for copying elements",
|
|
|
|
"consider calling the dedicated `copied` method",
|
2019-04-15 21:32:39 +00:00
|
|
|
format!(
|
|
|
|
"{}.copied()",
|
|
|
|
snippet_with_applicability(cx, root, "..", &mut applicability)
|
|
|
|
),
|
|
|
|
applicability,
|
|
|
|
)
|
|
|
|
} else {
|
|
|
|
span_lint_and_sugg(
|
|
|
|
cx,
|
|
|
|
MAP_CLONE,
|
|
|
|
replace,
|
2020-08-28 14:10:16 +00:00
|
|
|
"you are using an explicit closure for cloning elements",
|
|
|
|
"consider calling the dedicated `cloned` method",
|
2019-04-15 21:32:39 +00:00
|
|
|
format!(
|
|
|
|
"{}.cloned()",
|
|
|
|
snippet_with_applicability(cx, root, "..", &mut applicability)
|
|
|
|
),
|
|
|
|
applicability,
|
|
|
|
)
|
|
|
|
}
|
2019-01-15 06:09:47 +00:00
|
|
|
}
|