clang-tools-extra/clang-tidy/google/ExplicitMakePairCheck.cpp

   1 //===--- ExplicitMakePairCheck.cpp - clang-tidy -----------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "ExplicitMakePairCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12 #include "clang/ASTMatchers/ASTMatchers.h"
  13
  14 using namespace clang::ast_matchers;
  15
  16 namespace clang {
  17 namespace {
  18 AST_MATCHER(DeclRefExpr, hasExplicitTemplateArgs) {
  19   return Node.hasExplicitTemplateArgs();
  20 }
  21 } // namespace
  22
  23 namespace tidy::google::build {
  24
  25 void ExplicitMakePairCheck::registerMatchers(
  26     ast_matchers::MatchFinder *Finder) {
  27   // Look for std::make_pair with explicit template args. Ignore calls in
  28   // templates.
  29   Finder->addMatcher(
  30       callExpr(unless(isInTemplateInstantiation()),
  31                callee(expr(ignoringParenImpCasts(
  32                    declRefExpr(hasExplicitTemplateArgs(),
  33                                to(functionDecl(hasName("::std::make_pair"))))
  34                        .bind("declref")))))
  35           .bind("call"),
  36       this);
  37 }
  38
  39 void ExplicitMakePairCheck::check(const MatchFinder::MatchResult &Result) {
  40   const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
  41   const auto *DeclRef = Result.Nodes.getNodeAs<DeclRefExpr>("declref");
  42
  43   // Sanity check: The use might have overriden ::std::make_pair.
  44   if (Call->getNumArgs() != 2)
  45     return;
  46
  47   const Expr *Arg0 = Call->getArg(0)->IgnoreParenImpCasts();
  48   const Expr *Arg1 = Call->getArg(1)->IgnoreParenImpCasts();
  49
  50   // If types don't match, we suggest replacing with std::pair and explicit
  51   // template arguments. Otherwise just remove the template arguments from
  52   // make_pair.
  53   if (Arg0->getType() != Call->getArg(0)->getType() ||
  54       Arg1->getType() != Call->getArg(1)->getType()) {
  55     diag(Call->getBeginLoc(), "for C++11-compatibility, use pair directly")
  56         << FixItHint::CreateReplacement(
  57                SourceRange(DeclRef->getBeginLoc(), DeclRef->getLAngleLoc()),
  58                "std::pair<");
  59   } else {
  60     diag(Call->getBeginLoc(),
  61          "for C++11-compatibility, omit template arguments from make_pair")
  62         << FixItHint::CreateRemoval(
  63                SourceRange(DeclRef->getLAngleLoc(), DeclRef->getRAngleLoc()));
  64   }
  65 }
  66
  67 } // namespace tidy::google::build
  68 } // namespace clang