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//===- RedundantStringInitCheck.cpp - clang-tidy ----------------*- C++ -*-===//
//
// 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 "RedundantStringInitCheck.h"
#include "../utils/Matchers.h"
#include "clang/ASTMatchers/ASTMatchers.h"
using namespace clang::ast_matchers;
using namespace clang::tidy::matchers;
namespace clang {
namespace tidy {
namespace readability {
void RedundantStringInitCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
// Match string constructor.
const auto StringConstructorExpr = expr(anyOf(
cxxConstructExpr(argumentCountIs(1),
hasDeclaration(cxxMethodDecl(hasName("basic_string")))),
// If present, the second argument is the alloc object which must not
// be present explicitly.
cxxConstructExpr(argumentCountIs(2),
hasDeclaration(cxxMethodDecl(hasName("basic_string"))),
hasArgument(1, cxxDefaultArgExpr()))));
// Match a string constructor expression with an empty string literal.
const auto EmptyStringCtorExpr = cxxConstructExpr(
StringConstructorExpr,
hasArgument(0, ignoringParenImpCasts(stringLiteral(hasSize(0)))));
const auto EmptyStringCtorExprWithTemporaries =
cxxConstructExpr(StringConstructorExpr,
hasArgument(0, ignoringImplicit(EmptyStringCtorExpr)));
// Match a variable declaration with an empty string literal as initializer.
// Examples:
// string foo = "";
// string bar("");
Finder->addMatcher(
namedDecl(
varDecl(hasType(hasUnqualifiedDesugaredType(recordType(
hasDeclaration(cxxRecordDecl(hasName("basic_string")))))),
hasInitializer(expr(ignoringImplicit(anyOf(
EmptyStringCtorExpr,
EmptyStringCtorExprWithTemporaries)))
.bind("expr"))),
unless(parmVarDecl()))
.bind("decl"),
this);
}
void RedundantStringInitCheck::check(const MatchFinder::MatchResult &Result) {
const auto *CtorExpr = Result.Nodes.getNodeAs<Expr>("expr");
const auto *Decl = Result.Nodes.getNodeAs<NamedDecl>("decl");
diag(CtorExpr->getExprLoc(), "redundant string initialization")
<< FixItHint::CreateReplacement(CtorExpr->getSourceRange(),
Decl->getName());
}
} // namespace readability
} // namespace tidy
} // namespace clang
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