[clang-tools-extra] [clang-tidy] Add `modernize-use-as-const` check (PR #210554)

[Yanzuo Liu via cfe-commits]

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@@ -0,0 +1,101 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 "UseAsConstCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+
+namespace {
+
+AST_MATCHER(Expr, isLValueExpr) { return Node.isLValue(); }
+
+AST_MATCHER_P(ExplicitCastExpr, hasSourceExpressionAsWritten,
+              ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
+  const Expr *Sub = Node.getSubExprAsWritten();
+  return Sub != nullptr && InnerMatcher.matches(*Sub, Finder, Builder);
+}
+
+AST_MATCHER(ExplicitCastExpr, addsOnlyConst) {
+  const auto *Ref = Node.getTypeAsWritten()->getAs<LValueReferenceType>();
+  if (Ref == nullptr)
+    return false;
+  const Expr *Sub = Node.getSubExprAsWritten();
+  return Sub != nullptr &&
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zwuis wrote:

Ditto

https://github.com/llvm/llvm-project/pull/210554