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[clang-tidy] Add new check: modernize-use-concise-preprocessor-directives
Rewrites preprocessor conditions like `#if defined(MEOW)` as `#ifdef MEOW` and `#elif !defined(MEOW)` as `#elifndef MEOW`. Closes #132561.
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‎clang-tools-extra/clang-tidy/modernize/CMakeLists.txt‎

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@@ -30,6 +30,7 @@ add_clang_library(clangTidyModernizeModule STATIC
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UnaryStaticAssertCheck.cpp
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UseAutoCheck.cpp
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UseBoolLiteralsCheck.cpp
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UseConcisePreprocessorDirectivesCheck.cpp
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UseConstraintsCheck.cpp
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UseDefaultMemberInitCheck.cpp
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UseDesignatedInitializersCheck.cpp

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

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@@ -31,6 +31,7 @@
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#include "UnaryStaticAssertCheck.h"
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#include "UseAutoCheck.h"
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#include "UseBoolLiteralsCheck.h"
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#include "UseConcisePreprocessorDirectivesCheck.h"
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#include "UseConstraintsCheck.h"
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#include "UseDefaultMemberInitCheck.h"
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#include "UseDesignatedInitializersCheck.h"
@@ -76,6 +77,8 @@ class ModernizeModule : public ClangTidyModule {
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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<UseConcisePreprocessorDirectivesCheck>(
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"modernize-use-concise-preprocessor-directives");
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CheckFactories.registerCheck<UseDesignatedInitializersCheck>(
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"modernize-use-designated-initializers");
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CheckFactories.registerCheck<UseIntegerSignComparisonCheck>(

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

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//===--- UseConcisePreprocessorDirectivesCheck.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 "UseConcisePreprocessorDirectivesCheck.h"
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#include "clang/Basic/TokenKinds.h"
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#include "clang/Lex/Lexer.h"
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#include "clang/Lex/PPCallbacks.h"
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#include "clang/Lex/Preprocessor.h"
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namespace clang::tidy::modernize {
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namespace {
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class IfPreprocessorCallbacks final : public PPCallbacks {
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public:
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IfPreprocessorCallbacks(ClangTidyCheck &Check, Preprocessor &PP)
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: Check(Check), PP(PP) {}
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void If(SourceLocation Loc, SourceRange ConditionRange,
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ConditionValueKind) override {
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impl(Loc, ConditionRange, {"ifdef", "ifndef"});
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}
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void Elif(SourceLocation Loc, SourceRange ConditionRange, ConditionValueKind,
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SourceLocation) override {
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if (PP.getLangOpts().C23 || PP.getLangOpts().CPlusPlus23) {
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impl(Loc, ConditionRange, {"elifdef", "elifndef"});
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}
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}
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private:
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void impl(SourceLocation DirectiveLoc, SourceRange ConditionRange,
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const llvm::StringLiteral (&Replacements)[2]) {
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StringRef Condition =
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Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),
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PP.getSourceManager(), PP.getLangOpts());
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Lexer Lex(DirectiveLoc, PP.getLangOpts(), Condition.data(),
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Condition.data(), Condition.data() + Condition.size());
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Token Tok;
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bool Inverted = false; // The inverted form of #*def is #*ndef.
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std::size_t ParensNestingDepth = 0;
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for (;;) {
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if (Lex.LexFromRawLexer(Tok))
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return;
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if (Tok.is(tok::TokenKind::exclaim) ||
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(PP.getLangOpts().CPlusPlus &&
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Tok.is(tok::TokenKind::raw_identifier) &&
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Tok.getRawIdentifier() == "not"))
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Inverted = !Inverted;
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else if (Tok.is(tok::TokenKind::l_paren))
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++ParensNestingDepth;
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else
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break;
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}
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if (Tok.isNot(tok::TokenKind::raw_identifier) ||
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Tok.getRawIdentifier() != "defined")
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return;
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bool NoMoreTokens = Lex.LexFromRawLexer(Tok);
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if (Tok.is(tok::TokenKind::l_paren)) {
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if (NoMoreTokens)
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return;
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++ParensNestingDepth;
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NoMoreTokens = Lex.LexFromRawLexer(Tok);
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}
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if (Tok.isNot(tok::TokenKind::raw_identifier))
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return;
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StringRef Macro = Tok.getRawIdentifier();
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while (!NoMoreTokens) {
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NoMoreTokens = Lex.LexFromRawLexer(Tok);
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if (Tok.isNot(tok::TokenKind::r_paren))
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return;
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--ParensNestingDepth;
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}
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if (ParensNestingDepth != 0)
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return;
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Check.diag(DirectiveLoc,
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"preprocessor condition can be written more concisely")
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<< FixItHint::CreateReplacement(DirectiveLoc, Replacements[Inverted])
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<< FixItHint::CreateReplacement(ConditionRange, Macro);
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}
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ClangTidyCheck &Check;
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const Preprocessor &PP;
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};
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} // namespace
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void UseConcisePreprocessorDirectivesCheck::registerPPCallbacks(
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const SourceManager &, Preprocessor *PP, Preprocessor *) {
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PP->addPPCallbacks(std::make_unique<IfPreprocessorCallbacks>(*this, *PP));
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}
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} // namespace clang::tidy::modernize

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

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//===--- UseConcisePreprocessorDirectivesCheck.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_USECONCISEPREPROCESSORDIRECTIVESCHECK_H
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#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USECONCISEPREPROCESSORDIRECTIVESCHECK_H
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#include "../ClangTidyCheck.h"
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namespace clang::tidy::modernize {
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/// Shortens `#if` preprocessor conditions:
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///
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/// #if defined(MEOW) -> #ifdef MEOW
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/// #if !defined(MEOW) -> #ifndef MEOW
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///
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/// And, since C23 and C++23, shortens `#elif` conditions too:
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///
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/// #elif defined(MEOW) -> #elifdef MEOW
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/// #elif !defined(MEOW) -> #elifndef MEOW
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///
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/// User-facing documentation:
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/// https://clang.llvm.org/extra/clang-tidy/checks/modernize/use-concise-preprocessor-directives.html
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class UseConcisePreprocessorDirectivesCheck : public ClangTidyCheck {
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public:
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using ClangTidyCheck::ClangTidyCheck;
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void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
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Preprocessor *ModuleExpanderPP) override;
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};
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} // namespace clang::tidy::modernize
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#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USECONCISEPREPROCESSORDIRECTIVESCHECK_H

‎clang-tools-extra/docs/ReleaseNotes.rst‎

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@@ -142,6 +142,12 @@ New checks
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Finds unscoped (non-class) ``enum`` declarations and suggests using
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``enum class`` instead.
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- New :doc:`modernize-use-concise-preprocessor-directives
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<clang-tidy/checks/modernize/use-concise-preprocessor-directives>` check.
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Rewrites preprocessor conditions like ``#if defined(MEOW)`` as ``#ifdef MEOW``
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and ``#elif !defined(MEOW)`` as ``#elifndef MEOW``.
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- New :doc:`modernize-use-scoped-lock
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<clang-tidy/checks/modernize/use-scoped-lock>` check.
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‎clang-tools-extra/docs/clang-tidy/checks/list.rst‎

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@@ -300,6 +300,7 @@ Clang-Tidy Checks
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:doc:`modernize-unary-static-assert <modernize/unary-static-assert>`, "Yes"
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:doc:`modernize-use-auto <modernize/use-auto>`, "Yes"
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:doc:`modernize-use-bool-literals <modernize/use-bool-literals>`, "Yes"
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:doc:`modernize-use-concise-preprocessor-directives <modernize/use-concise-preprocessor-directives>`, "Yes"
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:doc:`modernize-use-constraints <modernize/use-constraints>`, "Yes"
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:doc:`modernize-use-default-member-init <modernize/use-default-member-init>`, "Yes"
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:doc:`modernize-use-designated-initializers <modernize/use-designated-initializers>`, "Yes"

‎clang-tools-extra/docs/clang-tidy/checks/modernize/use-concise-preprocessor-directives.rst‎

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.. title:: clang-tidy - modernize-use-concise-preprocessor-directives
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modernize-use-concise-preprocessor-directives
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=============================================
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Shortens `#if` preprocessor conditions:
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.. code-block:: c++
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#if defined(MEOW)
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#if !defined(MEOW)
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// becomes
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#ifdef MEOW
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#ifndef MEOW
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And, since C23 and C++23, shortens `#elif` conditions too:
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.. code-block:: c++
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#elif defined(MEOW)
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#elif !defined(MEOW)
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// becomes
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#elifdef MEOW
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#elifndef MEOW

‎clang-tools-extra/test/clang-tidy/checkers/modernize/use-concise-preprocessor-directives.cpp‎

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// RUN: %check_clang_tidy -std=c++98 -check-suffixes=ALL,CXX %s modernize-use-concise-preprocessor-directives %t
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// RUN: %check_clang_tidy -std=c++11 -check-suffixes=ALL,CXX %s modernize-use-concise-preprocessor-directives %t
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// RUN: %check_clang_tidy -std=c++14 -check-suffixes=ALL,CXX %s modernize-use-concise-preprocessor-directives %t
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// RUN: %check_clang_tidy -std=c++17 -check-suffixes=ALL,CXX %s modernize-use-concise-preprocessor-directives %t
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// RUN: %check_clang_tidy -std=c++20 -check-suffixes=ALL,CXX %s modernize-use-concise-preprocessor-directives %t
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// RUN: %check_clang_tidy -std=c++23-or-later -check-suffixes=ALL,23,CXX,CXX23 %s modernize-use-concise-preprocessor-directives %t
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// RUN: %check_clang_tidy -std=c99 -check-suffix=ALL %s modernize-use-concise-preprocessor-directives %t -- -- -x c
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// RUN: %check_clang_tidy -std=c11 -check-suffix=ALL %s modernize-use-concise-preprocessor-directives %t -- -- -x c
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// RUN: %check_clang_tidy -std=c23-or-later -check-suffix=ALL,23 %s modernize-use-concise-preprocessor-directives %t -- -- -x c
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifdef FOO
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#if defined(FOO)
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifdef BAR
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#elif defined(BAR)
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifdef FOO
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#if defined FOO
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifdef BAR
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#elif defined BAR
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifdef FOO
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#if (defined(FOO))
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// CHECK-MESSAGES-23: :[[@LINE+2]]:4: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: # elifdef BAR
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# elif (defined(BAR))
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifdef FOO
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#if (defined FOO)
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// CHECK-MESSAGES-23: :[[@LINE+2]]:4: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: # elifdef BAR
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# elif (defined BAR)
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if !defined(FOO)
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifndef BAR
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#elif !defined(BAR)
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#endif
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#ifdef __cplusplus
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// CHECK-MESSAGES-CXX: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-CXX: #ifndef FOO
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#if not defined(FOO)
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// CHECK-MESSAGES-CXX23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-CXX23: #elifndef BAR
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#elif not defined(BAR)
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#endif
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#endif // __cplusplus
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if !defined FOO
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifndef BAR
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#elif !defined BAR
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#endif
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#ifdef __cplusplus
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// CHECK-MESSAGES-CXX: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-CXX: #ifndef FOO
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#if not defined FOO
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// CHECK-MESSAGES-CXX23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-CXX23: #elifndef BAR
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#elif not defined BAR
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#endif
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#endif // __cplusplus
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if (!defined(FOO))
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifndef BAR
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#elif (!defined(BAR))
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if (!defined FOO)
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifndef BAR
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#elif (!defined BAR)
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if !(defined(FOO))
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifndef BAR
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#elif !(defined(BAR))
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if !(defined FOO)
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifndef BAR
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#elif !(defined BAR)
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#endif
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// These cases with many parentheses and negations are unrealistic, but
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// handling them doesn't really add any complexity to the implementation.
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// Test them for good measure.
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if !((!!(defined(FOO))))
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifdef BAR
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#elif ((!(!(defined(BAR)))))
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#endif
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// CHECK-MESSAGES-ALL: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-ALL: #ifndef FOO
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#if !((!!(defined FOO)))
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// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely [modernize-use-concise-preprocessor-directives]
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// CHECK-FIXES-23: #elifdef BAR
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#elif ((!(!(defined BAR))))
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#endif
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#if FOO
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#elif BAR
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#endif

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