forked from OSchip/llvm-project
297 lines
11 KiB
C++
297 lines
11 KiB
C++
//===--- PreferMemberInitializerCheck.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 "PreferMemberInitializerCheck.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/ASTMatchers/ASTMatchFinder.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 {
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namespace tidy {
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namespace cppcoreguidelines {
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static bool isControlStatement(const Stmt *S) {
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return isa<IfStmt, SwitchStmt, ForStmt, WhileStmt, DoStmt, ReturnStmt,
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GotoStmt, CXXTryStmt, CXXThrowExpr>(S);
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}
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static bool isNoReturnCallStatement(const Stmt *S) {
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const auto *Call = dyn_cast<CallExpr>(S);
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if (!Call)
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return false;
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const FunctionDecl *Func = Call->getDirectCallee();
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if (!Func)
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return false;
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return Func->isNoReturn();
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}
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static bool isLiteral(const Expr *E) {
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return isa<StringLiteral, CharacterLiteral, IntegerLiteral, FloatingLiteral,
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CXXBoolLiteralExpr, CXXNullPtrLiteralExpr>(E);
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}
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static bool isUnaryExprOfLiteral(const Expr *E) {
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if (const auto *UnOp = dyn_cast<UnaryOperator>(E))
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return isLiteral(UnOp->getSubExpr());
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return false;
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}
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static bool shouldBeDefaultMemberInitializer(const Expr *Value) {
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if (isLiteral(Value) || isUnaryExprOfLiteral(Value))
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return true;
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if (const auto *DRE = dyn_cast<DeclRefExpr>(Value))
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return isa<EnumConstantDecl>(DRE->getDecl());
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return false;
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}
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namespace {
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AST_MATCHER_P(FieldDecl, indexNotLessThan, unsigned, Index) {
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return Node.getFieldIndex() >= Index;
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}
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} // namespace
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// Checks if Field is initialised using a field that will be initialised after
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// it.
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// TODO: Probably should guard against function calls that could have side
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// effects or if they do reference another field that's initialized before this
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// field, but is modified before the assignment.
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static bool isSafeAssignment(const FieldDecl *Field, const Expr *Init,
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const CXXConstructorDecl *Context) {
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auto MemberMatcher =
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memberExpr(hasObjectExpression(cxxThisExpr()),
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member(fieldDecl(indexNotLessThan(Field->getFieldIndex()))));
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auto DeclMatcher = declRefExpr(
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to(varDecl(unless(parmVarDecl()), hasDeclContext(equalsNode(Context)))));
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return match(expr(anyOf(MemberMatcher, DeclMatcher,
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hasDescendant(MemberMatcher),
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hasDescendant(DeclMatcher))),
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*Init, Field->getASTContext())
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.empty();
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}
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static const std::pair<const FieldDecl *, const Expr *>
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isAssignmentToMemberOf(const CXXRecordDecl *Rec, const Stmt *S,
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const CXXConstructorDecl *Ctor) {
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if (const auto *BO = dyn_cast<BinaryOperator>(S)) {
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if (BO->getOpcode() != BO_Assign)
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return std::make_pair(nullptr, nullptr);
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const auto *ME = dyn_cast<MemberExpr>(BO->getLHS()->IgnoreParenImpCasts());
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if (!ME)
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return std::make_pair(nullptr, nullptr);
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const auto *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
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if (!Field)
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return std::make_pair(nullptr, nullptr);
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if (!isa<CXXThisExpr>(ME->getBase()))
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return std::make_pair(nullptr, nullptr);
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const Expr *Init = BO->getRHS()->IgnoreParenImpCasts();
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if (isSafeAssignment(Field, Init, Ctor))
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return std::make_pair(Field, Init);
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} else if (const auto *COCE = dyn_cast<CXXOperatorCallExpr>(S)) {
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if (COCE->getOperator() != OO_Equal)
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return std::make_pair(nullptr, nullptr);
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const auto *ME =
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dyn_cast<MemberExpr>(COCE->getArg(0)->IgnoreParenImpCasts());
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if (!ME)
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return std::make_pair(nullptr, nullptr);
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const auto *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
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if (!Field)
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return std::make_pair(nullptr, nullptr);
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if (!isa<CXXThisExpr>(ME->getBase()))
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return std::make_pair(nullptr, nullptr);
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const Expr *Init = COCE->getArg(1)->IgnoreParenImpCasts();
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if (isSafeAssignment(Field, Init, Ctor))
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return std::make_pair(Field, Init);
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}
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return std::make_pair(nullptr, nullptr);
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}
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PreferMemberInitializerCheck::PreferMemberInitializerCheck(
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StringRef Name, ClangTidyContext *Context)
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: ClangTidyCheck(Name, Context),
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IsUseDefaultMemberInitEnabled(
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Context->isCheckEnabled("modernize-use-default-member-init")),
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UseAssignment(OptionsView("modernize-use-default-member-init",
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Context->getOptions().CheckOptions, Context)
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.get("UseAssignment", false)) {}
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void PreferMemberInitializerCheck::storeOptions(
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ClangTidyOptions::OptionMap &Opts) {
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Options.store(Opts, "UseAssignment", UseAssignment);
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}
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void PreferMemberInitializerCheck::registerMatchers(MatchFinder *Finder) {
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Finder->addMatcher(
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cxxConstructorDecl(hasBody(compoundStmt()), unless(isInstantiated()))
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.bind("ctor"),
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this);
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}
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void PreferMemberInitializerCheck::check(
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const MatchFinder::MatchResult &Result) {
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const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
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const auto *Body = cast<CompoundStmt>(Ctor->getBody());
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const CXXRecordDecl *Class = Ctor->getParent();
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bool FirstToCtorInits = true;
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for (const Stmt *S : Body->body()) {
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if (S->getBeginLoc().isMacroID()) {
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StringRef MacroName = Lexer::getImmediateMacroName(
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S->getBeginLoc(), *Result.SourceManager, getLangOpts());
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if (MacroName.contains_lower("assert"))
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return;
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}
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if (isControlStatement(S))
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return;
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if (isNoReturnCallStatement(S))
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return;
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if (const auto *CondOp = dyn_cast<ConditionalOperator>(S)) {
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if (isNoReturnCallStatement(CondOp->getLHS()) ||
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isNoReturnCallStatement(CondOp->getRHS()))
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return;
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}
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const FieldDecl *Field;
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const Expr *InitValue;
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std::tie(Field, InitValue) = isAssignmentToMemberOf(Class, S, Ctor);
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if (Field) {
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if (IsUseDefaultMemberInitEnabled && getLangOpts().CPlusPlus11 &&
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Ctor->isDefaultConstructor() &&
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(getLangOpts().CPlusPlus20 || !Field->isBitField()) &&
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!Field->hasInClassInitializer() &&
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(!isa<RecordDecl>(Class->getDeclContext()) ||
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!cast<RecordDecl>(Class->getDeclContext())->isUnion()) &&
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shouldBeDefaultMemberInitializer(InitValue)) {
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bool InvalidFix = false;
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SourceLocation FieldEnd =
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Lexer::getLocForEndOfToken(Field->getSourceRange().getEnd(), 0,
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*Result.SourceManager, getLangOpts());
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InvalidFix |= FieldEnd.isInvalid() || FieldEnd.isMacroID();
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SourceLocation SemiColonEnd;
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if (auto NextToken = Lexer::findNextToken(
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S->getEndLoc(), *Result.SourceManager, getLangOpts()))
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SemiColonEnd = NextToken->getEndLoc();
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else
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InvalidFix = true;
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auto Diag =
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diag(S->getBeginLoc(), "%0 should be initialized in an in-class"
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" default member initializer")
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<< Field;
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if (!InvalidFix) {
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CharSourceRange StmtRange =
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CharSourceRange::getCharRange(S->getBeginLoc(), SemiColonEnd);
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SmallString<128> Insertion(
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{UseAssignment ? " = " : "{",
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Lexer::getSourceText(
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CharSourceRange(InitValue->getSourceRange(), true),
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*Result.SourceManager, getLangOpts()),
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UseAssignment ? "" : "}"});
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Diag << FixItHint::CreateInsertion(FieldEnd, Insertion)
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<< FixItHint::CreateRemoval(StmtRange);
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}
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} else {
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StringRef InsertPrefix = "";
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SourceLocation InsertPos;
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bool AddComma = false;
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bool InvalidFix = false;
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unsigned Index = Field->getFieldIndex();
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const CXXCtorInitializer *LastInListInit = nullptr;
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for (const CXXCtorInitializer *Init : Ctor->inits()) {
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if (!Init->isWritten())
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continue;
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if (Init->isMemberInitializer() &&
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Index < Init->getMember()->getFieldIndex()) {
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InsertPos = Init->getSourceLocation();
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// There are initializers after the one we are inserting, so add a
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// comma after this insertion in order to not break anything.
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AddComma = true;
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break;
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}
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LastInListInit = Init;
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}
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if (InsertPos.isInvalid()) {
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if (LastInListInit) {
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InsertPos = Lexer::getLocForEndOfToken(
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LastInListInit->getRParenLoc(), 0, *Result.SourceManager,
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getLangOpts());
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// Inserting after the last constructor initializer, so we need a
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// comma.
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InsertPrefix = ", ";
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} else {
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InsertPos = Lexer::getLocForEndOfToken(
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Ctor->getTypeSourceInfo()
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->getTypeLoc()
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.getAs<clang::FunctionTypeLoc>()
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.getLocalRangeEnd(),
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0, *Result.SourceManager, getLangOpts());
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// If this is first time in the loop, there are no initializers so
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// `:` declares member initialization list. If this is a subsequent
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// pass then we have already inserted a `:` so continue with a
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// comma.
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InsertPrefix = FirstToCtorInits ? " : " : ", ";
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}
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}
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InvalidFix |= InsertPos.isMacroID();
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SourceLocation SemiColonEnd;
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if (auto NextToken = Lexer::findNextToken(
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S->getEndLoc(), *Result.SourceManager, getLangOpts()))
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SemiColonEnd = NextToken->getEndLoc();
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else
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InvalidFix = true;
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auto Diag =
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diag(S->getBeginLoc(), "%0 should be initialized in a member"
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" initializer of the constructor")
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<< Field;
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if (!InvalidFix) {
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CharSourceRange StmtRange =
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CharSourceRange::getCharRange(S->getBeginLoc(), SemiColonEnd);
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SmallString<128> Insertion(
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{InsertPrefix, Field->getName(), "(",
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Lexer::getSourceText(
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CharSourceRange(InitValue->getSourceRange(), true),
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*Result.SourceManager, getLangOpts()),
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AddComma ? "), " : ")"});
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Diag << FixItHint::CreateInsertion(InsertPos, Insertion,
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FirstToCtorInits)
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<< FixItHint::CreateRemoval(StmtRange);
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FirstToCtorInits = false;
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}
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}
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}
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}
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}
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} // namespace cppcoreguidelines
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} // namespace tidy
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} // namespace clang
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