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|
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::msrvs::{self, Msrv};
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::{is_copy, is_type_diagnostic_item};
use clippy_utils::{is_diag_trait_item, peel_blocks};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::mir::Mutability;
use rustc_middle::ty;
use rustc_middle::ty::adjustment::Adjust;
use rustc_span::symbol::Ident;
use rustc_span::{sym, Span};
use super::MAP_CLONE;
pub(super) fn check(cx: &LateContext<'_>, e: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>, msrv: &Msrv) {
if_chain! {
if let Some(method_id) = cx.typeck_results().type_dependent_def_id(e.hir_id);
if cx.tcx.impl_of_method(method_id)
.map_or(false, |id| is_type_diagnostic_item(cx, cx.tcx.type_of(id), sym::Option))
|| is_diag_trait_item(cx, method_id, sym::Iterator);
if let hir::ExprKind::Closure(&hir::Closure{ body, .. }) = arg.kind;
then {
let closure_body = cx.tcx.hir().body(body);
let closure_expr = peel_blocks(closure_body.value);
match closure_body.params[0].pat.kind {
hir::PatKind::Ref(inner, hir::Mutability::Not) => if let hir::PatKind::Binding(
hir::BindingAnnotation::NONE, .., name, None
) = inner.kind {
if ident_eq(name, closure_expr) {
lint_explicit_closure(cx, e.span, recv.span, true, msrv);
}
},
hir::PatKind::Binding(hir::BindingAnnotation::NONE, .., name, None) => {
match closure_expr.kind {
hir::ExprKind::Unary(hir::UnOp::Deref, inner) => {
if ident_eq(name, inner) {
if let ty::Ref(.., Mutability::Not) = cx.typeck_results().expr_ty(inner).kind() {
lint_explicit_closure(cx, e.span, recv.span, true, msrv);
}
}
},
hir::ExprKind::MethodCall(method, obj, [], _) => if_chain! {
if ident_eq(name, obj) && method.ident.name == sym::clone;
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);
if cx.tcx.lang_items().clone_trait().map_or(false, |id| id == trait_id);
// 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_explicit_closure(cx, e.span, recv.span, copy, msrv);
}
} else {
lint_needless_cloning(cx, e.span, recv.span);
}
}
},
_ => {},
}
},
_ => {},
}
}
}
}
fn ident_eq(name: Ident, path: &hir::Expr<'_>) -> bool {
if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = path.kind {
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_explicit_closure(cx: &LateContext<'_>, replace: Span, root: Span, is_copy: bool, msrv: &Msrv) {
let mut applicability = Applicability::MachineApplicable;
let (message, sugg_method) = if is_copy && msrv.meets(msrvs::ITERATOR_COPIED) {
("you are using an explicit closure for copying elements", "copied")
} else {
("you are using an explicit closure for cloning elements", "cloned")
};
span_lint_and_sugg(
cx,
MAP_CLONE,
replace,
message,
&format!("consider calling the dedicated `{sugg_method}` method"),
format!(
"{}.{sugg_method}()",
snippet_with_applicability(cx, root, "..", &mut applicability),
),
applicability,
);
}
|
