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Auto merge of #6871 - camsteffen:redundant-closure-macro, r=Manishearth

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Fix redundant closure with macros

changelog: Fix redundant_closure FPs with macros

Fixes #6732
Fixes #6850
Fixes #4354 (addresses the error message confusion)
This commit is contained in:
bors 2021-03-08 21:32:21 +00:00
commit 2cb5bbf80c
4 changed files with 98 additions and 40 deletions
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32
clippy_lints/src/eta_reduction.rs
View file

@ -10,6 +10,8 @@ use crate::utils::{
implements_trait, is_adjusted, iter_input_pats, snippet_opt, span_lint_and_sugg, span_lint_and_then,
type_is_unsafe_function,
};
use clippy_utils::higher;
use clippy_utils::higher::VecArgs;
declare_clippy_lint! {
/// **What it does:** Checks for closures which just call another function where
@ -74,7 +76,10 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
match expr.kind {
ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) => {
for arg in args {
check_closure(cx, arg)
// skip `foo(macro!())`
if arg.span.ctxt() == expr.span.ctxt() {
check_closure(cx, arg)
}
}
},
_ => (),
@ -87,6 +92,23 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) {
let body = cx.tcx.hir().body(eid);
let ex = &body.value;
if ex.span.ctxt() != expr.span.ctxt() {
if let Some(VecArgs::Vec(&[])) = higher::vec_macro(cx, ex) {
// replace `|| vec![]` with `Vec::new`
span_lint_and_sugg(
cx,
REDUNDANT_CLOSURE,
expr.span,
"redundant closure",
"replace the closure with `Vec::new`",
"std::vec::Vec::new".into(),
Applicability::MachineApplicable,
);
}
// skip `foo(|| macro!())`
return;
}
if_chain!(
if let ExprKind::Call(ref caller, ref args) = ex.kind;
@ -107,11 +129,11 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) {
if compare_inputs(&mut iter_input_pats(decl, body), &mut args.iter());
then {
span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure found", |diag| {
span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure", |diag| {
if let Some(snippet) = snippet_opt(cx, caller.span) {
diag.span_suggestion(
expr.span,
"remove closure as shown",
"replace the closure with the function itself",
snippet,
Applicability::MachineApplicable,
);
@ -141,8 +163,8 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) {
cx,
REDUNDANT_CLOSURE_FOR_METHOD_CALLS,
expr.span,
"redundant closure found",
"remove closure as shown",
"redundant closure",
"replace the closure with the method itself",
format!("{}::{}", name, path.ident.name),
Applicability::MachineApplicable,
);