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[clang-tidy] add check to suggest replacement of nested std::min or std::max with initializer lists
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‎clang-tools-extra/clang-tidy/modernize/CMakeLists.txt

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@@ -16,6 +16,7 @@ add_clang_library(clangTidyModernizeModule
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MakeSharedCheck.cpp
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MakeSmartPtrCheck.cpp
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MakeUniqueCheck.cpp
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MinMaxUseInitializerListCheck.cpp
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ModernizeTidyModule.cpp
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PassByValueCheck.cpp
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RawStringLiteralCheck.cpp

‎clang-tools-extra/clang-tidy/modernize/MinMaxUseInitializerListCheck.cpp

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//===--- MinMaxUseInitializerListCheck.cpp - clang-tidy -------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "MinMaxUseInitializerListCheck.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "clang/Frontend/CompilerInstance.h"
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#include "clang/Lex/Lexer.h"
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using namespace clang::ast_matchers;
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namespace clang::tidy::modernize {
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MinMaxUseInitializerListCheck::MinMaxUseInitializerListCheck(
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StringRef Name, ClangTidyContext *Context)
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: ClangTidyCheck(Name, Context),
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Inserter(Options.getLocalOrGlobal("IncludeStyle",
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utils::IncludeSorter::IS_LLVM),
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areDiagsSelfContained()) {}
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void MinMaxUseInitializerListCheck::storeOptions(
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ClangTidyOptions::OptionMap &Opts) {
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Options.store(Opts, "IncludeStyle", Inserter.getStyle());
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}
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void MinMaxUseInitializerListCheck::registerMatchers(MatchFinder *Finder) {
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Finder->addMatcher(
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callExpr(
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callee(functionDecl(hasName("::std::max"))),
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hasAnyArgument(callExpr(callee(functionDecl(hasName("::std::max"))))),
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unless(
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hasParent(callExpr(callee(functionDecl(hasName("::std::max")))))))
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.bind("maxCall"),
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this);
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Finder->addMatcher(
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callExpr(
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callee(functionDecl(hasName("::std::min"))),
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hasAnyArgument(callExpr(callee(functionDecl(hasName("::std::min"))))),
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unless(
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hasParent(callExpr(callee(functionDecl(hasName("::std::min")))))))
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.bind("minCall"),
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this);
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}
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void MinMaxUseInitializerListCheck::registerPPCallbacks(
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const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
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Inserter.registerPreprocessor(PP);
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}
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void MinMaxUseInitializerListCheck::check(
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const MatchFinder::MatchResult &Result) {
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const auto *MaxCall = Result.Nodes.getNodeAs<CallExpr>("maxCall");
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const auto *MinCall = Result.Nodes.getNodeAs<CallExpr>("minCall");
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const CallExpr *TopCall = MaxCall ? MaxCall : MinCall;
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if (!TopCall) {
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return;
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}
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const QualType ResultType =
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TopCall->getDirectCallee()->getReturnType().getNonReferenceType();
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const Expr *FirstArg = nullptr;
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const Expr *LastArg = nullptr;
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std::vector<const Expr *> Args;
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findArgs(TopCall, &FirstArg, &LastArg, Args);
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if (!FirstArg || !LastArg || Args.size() <= 2) {
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return;
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}
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std::string ReplacementText = "{";
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for (const Expr *Arg : Args) {
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QualType ArgType = Arg->getType();
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bool CastNeeded =
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ArgType.getCanonicalType() != ResultType.getCanonicalType();
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if (CastNeeded)
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ReplacementText += "static_cast<" + ResultType.getAsString() + ">(";
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ReplacementText += Lexer::getSourceText(
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CharSourceRange::getTokenRange(Arg->getSourceRange()),
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*Result.SourceManager, Result.Context->getLangOpts());
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if (CastNeeded)
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ReplacementText += ")";
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ReplacementText += ", ";
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}
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ReplacementText = ReplacementText.substr(0, ReplacementText.size() - 2) + "}";
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diag(TopCall->getBeginLoc(),
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"do not use nested std::%0 calls, use %1 instead")
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<< TopCall->getDirectCallee()->getName() << ReplacementText
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<< FixItHint::CreateReplacement(
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CharSourceRange::getTokenRange(
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FirstArg->getBeginLoc(),
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Lexer::getLocForEndOfToken(TopCall->getEndLoc(), 0,
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Result.Context->getSourceManager(),
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Result.Context->getLangOpts())
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.getLocWithOffset(-2)),
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ReplacementText)
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<< Inserter.createMainFileIncludeInsertion("<algorithm>");
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}
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void MinMaxUseInitializerListCheck::findArgs(const CallExpr *Call,
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const Expr **First,
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const Expr **Last,
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std::vector<const Expr *> &Args) {
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if (!Call) {
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return;
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}
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const FunctionDecl *Callee = Call->getDirectCallee();
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if (!Callee) {
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return;
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}
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for (const Expr *Arg : Call->arguments()) {
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if (!*First)
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*First = Arg;
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const CallExpr *InnerCall = dyn_cast<CallExpr>(Arg);
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if (InnerCall && InnerCall->getDirectCallee() &&
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InnerCall->getDirectCallee()->getNameAsString() ==
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Call->getDirectCallee()->getNameAsString()) {
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findArgs(InnerCall, First, Last, Args);
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} else
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Args.push_back(Arg);
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*Last = Arg;
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}
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}
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} // namespace clang::tidy::modernize

‎clang-tools-extra/clang-tidy/modernize/MinMaxUseInitializerListCheck.h

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//===--- MinMaxUseInitializerListCheck.h - clang-tidy -----------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_MINMAXUSEINITIALIZERLISTCHECK_H
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#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_MINMAXUSEINITIALIZERLISTCHECK_H
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#include "../ClangTidyCheck.h"
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#include "../utils/IncludeInserter.h"
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namespace clang::tidy::modernize {
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/// Transforms the repeated calls to `std::min` and `std::max` into a single
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/// call using initializer lists.
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///
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/// It identifies cases where `std::min` or `std::max` is used to find the
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/// minimum or maximum value among more than two items through repeated calls.
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/// The check replaces these calls with a single call to `std::min` or
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/// `std::max` that uses an initializer list. This makes the code slightly more
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/// efficient.
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/// \n\n
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/// For example:
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///
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/// \code
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/// int a = std::max(std::max(i, j), k);
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/// \endcode
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///
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/// This code is transformed to:
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///
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/// \code
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/// int a = std::max({i, j, k});
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/// \endcode
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class MinMaxUseInitializerListCheck : public ClangTidyCheck {
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public:
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MinMaxUseInitializerListCheck(StringRef Name, ClangTidyContext *Context);
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bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
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return LangOpts.CPlusPlus11;
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}
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void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
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void registerMatchers(ast_matchers::MatchFinder *Finder) override;
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void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
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Preprocessor *ModuleExpanderPP) override;
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void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
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private:
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utils::IncludeInserter Inserter;
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void findArgs(const CallExpr *call, const Expr **first, const Expr **last,
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std::vector<const Expr *> &args);
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};
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} // namespace clang::tidy::modernize
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#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_MINMAXUSEINITIALIZERLISTCHECK_H

‎clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp

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#include "MacroToEnumCheck.h"
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#include "MakeSharedCheck.h"
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#include "MakeUniqueCheck.h"
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#include "MinMaxUseInitializerListCheck.h"
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#include "PassByValueCheck.h"
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#include "RawStringLiteralCheck.h"
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#include "RedundantVoidArgCheck.h"
@@ -68,6 +69,8 @@ class ModernizeModule : public ClangTidyModule {
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CheckFactories.registerCheck<MacroToEnumCheck>("modernize-macro-to-enum");
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CheckFactories.registerCheck<MakeSharedCheck>("modernize-make-shared");
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CheckFactories.registerCheck<MakeUniqueCheck>("modernize-make-unique");
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CheckFactories.registerCheck<MinMaxUseInitializerListCheck>(
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"modernize-min-max-use-initializer-list");
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CheckFactories.registerCheck<PassByValueCheck>("modernize-pass-by-value");
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CheckFactories.registerCheck<UseDesignatedInitializersCheck>(
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"modernize-use-designated-initializers");

‎clang-tools-extra/docs/ReleaseNotes.rst

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@@ -110,6 +110,12 @@ New checks
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Detects error-prone Curiously Recurring Template Pattern usage, when the CRTP
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can be constructed outside itself and the derived class.
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- New :doc:`modernize-min-max-use-initializer-list
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<clang-tidy/checks/modernize/min-max-use-initializer-list>` check.
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Replaces chained ``std::min`` and ``std::max`` calls that can be written as
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initializer lists.
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- New :doc:`modernize-use-designated-initializers
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<clang-tidy/checks/modernize/use-designated-initializers>` check.
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‎clang-tools-extra/docs/clang-tidy/checks/list.rst

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@@ -274,6 +274,7 @@ Clang-Tidy Checks
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:doc:`modernize-macro-to-enum <modernize/macro-to-enum>`, "Yes"
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:doc:`modernize-make-shared <modernize/make-shared>`, "Yes"
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:doc:`modernize-make-unique <modernize/make-unique>`, "Yes"
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:doc:`modernize-min-max-use-initializer-list <modernize/min-max-use-initializer-list>`, "Yes"
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:doc:`modernize-pass-by-value <modernize/pass-by-value>`, "Yes"
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:doc:`modernize-raw-string-literal <modernize/raw-string-literal>`, "Yes"
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:doc:`modernize-redundant-void-arg <modernize/redundant-void-arg>`, "Yes"
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:doc:`performance-inefficient-algorithm <performance/inefficient-algorithm>`, "Yes"
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:doc:`performance-inefficient-string-concatenation <performance/inefficient-string-concatenation>`,
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:doc:`performance-inefficient-vector-operation <performance/inefficient-vector-operation>`, "Yes"
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:doc:`performance-modernize-min-max-use-initializer-list <performance/modernize-min-max-use-initializer-list>`,
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:doc:`performance-move-const-arg <performance/move-const-arg>`, "Yes"
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:doc:`performance-move-constructor-init <performance/move-constructor-init>`,
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:doc:`performance-no-automatic-move <performance/no-automatic-move>`,

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