[clang-tools-extra] [clang-tidy] Add readability-redundant-lambda-parameter-list (PR #190438)

[Daniil Dudkin via cfe-commits]

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@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "RedundantLambdaParameterListCheck.h"
+#include "../utils/LexerUtils.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::readability {
+
+namespace {
+
+AST_MATCHER(LambdaExpr, hasRedundantParens) {
+  return Node.hasExplicitParameters() &&
+         Node.getCallOperator()->getNumParams() == 0 &&
+         !Node.getCallOperator()->getTrailingRequiresClause();
+}
+
+} // namespace
+
+void RedundantLambdaParameterListCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(lambdaExpr(hasRedundantParens()).bind("lambda"), this);
+}
+
+void RedundantLambdaParameterListCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *Lambda = Result.Nodes.getNodeAs<LambdaExpr>("lambda");
+
+  const LangOptions &LangOpts = getLangOpts();
+
+  const FunctionTypeLoc FTL = Lambda->getCallOperator()->getFunctionTypeLoc();
+  const SourceLocation LParenLoc = FTL.getLParenLoc();
+  const SourceLocation RParenLoc = FTL.getRParenLoc();
+
+  if (LParenLoc.isInvalid() || RParenLoc.isInvalid())
+    return;
+
+  // Ensure parens are truly empty (reject "(void)")
----------------
unterumarmung wrote:

I think we should not reject `(void)` - it is still useless.

@localspook wdyt?

https://github.com/llvm/llvm-project/pull/190438