Allow let () = .. as type inference for let_unit_value

rust-lang · Jun 27, 2022 · d773ce0 · d773ce0
1 parent 51e6175
commit d773ce0
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Showing 3 changed files with 15 additions and 8 deletions.
diff --git a/clippy_lints/src/unit_types/let_unit_value.rs b/clippy_lints/src/unit_types/let_unit_value.rs
@@ -19,20 +19,23 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
  && !in_external_macro(cx.sess(), stmt.span)
  && cx.typeck_results().pat_ty(local.pat).is_unit()
  {
- if local.ty.is_some() && expr_needs_inferred_result(cx, init) {
- if !matches!(local.pat.kind, PatKind::Wild) {
+ if (local.ty.map_or(false, |ty| !matches!(ty.kind, TyKind::Infer))
+ || matches!(local.pat.kind, PatKind::Tuple([], None)))
+ && expr_needs_inferred_result(cx, init)
+ {
+ if !matches!(local.pat.kind, PatKind::Wild | PatKind::Tuple([], None)) {
  span_lint_and_then(
  cx,
  LET_UNIT_VALUE,
  stmt.span,
  "this let-binding has unit value",
  |diag| {
-  diag.span_suggestion(
-  local.pat.span,
-  "use a wild (`_`) binding",
-  "_",
-  Applicability::MaybeIncorrect, // snippet
-  );
+ diag.span_suggestion(
+ local.pat.span,
+ "use a wild (`_`) binding",
+ "_",
+ Applicability::MaybeIncorrect, // snippet
+ );
  },
  );
  }

diff --git a/tests/ui/let_unit.fixed b/tests/ui/let_unit.fixed
@@ -162,4 +162,6 @@ fn _returns_generic() {
  let _: () = opt;
  }
  }
+
+ let () = f();
 }
diff --git a/tests/ui/let_unit.rs b/tests/ui/let_unit.rs
@@ -162,4 +162,6 @@ fn _returns_generic() {
  let _: () = opt;
  }
  }
+
+ let () = f();
 }