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Auto merge of #10844 - Centri3:let_unit_value, r=Alexendoo

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Don't lint `let_unit_value` when `()` is explicit

since these are explicitly written (and not the result of a function call or anything else), they should be allowed, as they are both useful in some cases described in #9048

Fixes #9048

changelog: [`let_unit_value`]: Don't lint when `()` is explicit
This commit is contained in:
bors 2024-01-05 16:13:38 +00:00
commit 394f63fe94
7 changed files with 71 additions and 127 deletions
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21
clippy_lints/src/unit_types/let_unit_value.rs
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@ -13,12 +13,31 @@ use rustc_middle::ty;
use super::LET_UNIT_VALUE;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, local: &'tcx Local<'_>) {
// skip `let () = { ... }`
if let PatKind::Tuple(fields, ..) = local.pat.kind
&& fields.is_empty()
{
return;
}
if let Some(init) = local.init
&& !local.pat.span.from_expansion()
&& !in_external_macro(cx.sess(), local.span)
&& !is_from_async_await(local.span)
&& cx.typeck_results().pat_ty(local.pat).is_unit()
{
// skip `let awa = ()`
if let ExprKind::Tup([]) = init.kind {
return;
}
// skip `let _: () = { ... }`
if let Some(ty) = local.ty
&& let TyKind::Tup([]) = ty.kind
{
return;
}
if (local.ty.map_or(false, |ty| !matches!(ty.kind, TyKind::Infer))
|| matches!(local.pat.kind, PatKind::Tuple([], ddpos) if ddpos.as_opt_usize().is_none()))
&& expr_needs_inferred_result(cx, init)
@ -34,7 +53,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, local: &'tcx Local<'_>) {
|diag| {
diag.span_suggestion(
local.pat.span,
"use a wild (`_`) binding",
"use a wildcard binding",
"_",
Applicability::MaybeIncorrect, // snippet
);