[clang-tools-extra] [clang-tidy] Add `performance-explicit-move-constructor` check (PR #122599)

[via cfe-commits]

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@@ -0,0 +1,73 @@
+//===--- ExplicitMoveConstructorCheck.cpp - clang-tidy --------------------===//
+//
+// 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 "ExplicitMoveConstructorCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::performance {
+
+static SourceRange findExplicitToken(const CXXConstructorDecl *Ctor,
+                                     const SourceManager &Source,
+                                     const LangOptions &LangOpts) {
+  SourceLocation CurrentLoc = Ctor->getBeginLoc();
+  SourceLocation EndLoc = Ctor->getEndLoc();
+  Token Tok;
+
+  do {
+    const bool failed = Lexer::getRawToken(CurrentLoc, Tok, Source, LangOpts);
+
+    if (failed)
+      return {};
+
+    if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == "explicit")
+      return {Tok.getLocation(), Tok.getEndLoc()};
+
+    CurrentLoc = Tok.getEndLoc();
+  } while (Tok.isNot(tok::eof) && CurrentLoc < EndLoc);
+
+  return {};
+}
+
+void ExplicitMoveConstructorCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      cxxRecordDecl(
+          has(cxxConstructorDecl(isMoveConstructor(), isExplicit(),
+                                 unless(isDeleted()))
+                  .bind("move-ctor")),
+          has(cxxConstructorDecl(isCopyConstructor(), unless(isDeleted()))
+                  .bind("copy-ctor"))),
+      this);
+}
+
+void ExplicitMoveConstructorCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *MoveCtor =
+      Result.Nodes.getNodeAs<CXXConstructorDecl>("move-ctor");
+  const auto *CopyCtor =
+      Result.Nodes.getNodeAs<CXXConstructorDecl>("copy-ctor");
+
+  if (!MoveCtor || !CopyCtor)
+    return;
+
+  auto Diag =
+      diag(MoveCtor->getLocation(),
+           "copy constructor may be called instead of move constructor");
+  SourceRange ExplicitTokenRange =
----------------
EugeneZelenko wrote:

```suggestion
  const SourceRange ExplicitTokenRange =
```

https://github.com/llvm/llvm-project/pull/122599