[clang-tools-extra] [clang-tidy] Add modernize-nlohmann-json-explicit-conversions check (PR #126425)

[Mike Crowe via cfe-commits]

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@@ -0,0 +1,72 @@
+//===--- NlohmannJsonExplicitConversionsCheck.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 "NlohmannJsonExplicitConversionsCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+
+void NlohmannJsonExplicitConversionsCheck::registerMatchers(
+    MatchFinder *Finder) {
+  auto Matcher =
+      cxxMemberCallExpr(
+          on(expr().bind("arg")),
+          callee(cxxConversionDecl(ofClass(hasName("nlohmann::basic_json")))
+                     .bind("conversionDecl")))
+          .bind("conversionCall");
+  Finder->addMatcher(Matcher, this);
+}
+
+void NlohmannJsonExplicitConversionsCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *Decl =
+      Result.Nodes.getNodeAs<CXXConversionDecl>("conversionDecl");
+  const auto *Call =
+      Result.Nodes.getNodeAs<CXXMemberCallExpr>("conversionCall");
+  const auto *Arg = Result.Nodes.getNodeAs<Expr>("arg");
+
+  const QualType DestinationType = Decl->getConversionType();
+  std::string DestinationTypeStr =
+      DestinationType.getAsString(Result.Context->getPrintingPolicy());
+  if (DestinationTypeStr == "std::basic_string<char>")
+    DestinationTypeStr = "std::string";
+
+  SourceRange ExprRange = Call->getSourceRange();
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mikecrowe wrote:

Thanks!

https://github.com/llvm/llvm-project/pull/126425