xref: /llvm-project/clang-tools-extra/clang-tidy/google/ExplicitMakePairCheck.cpp (revision 7d2ea6c422d3f5712b7253407005e1a465a76946)
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 {
AST_MATCHER(DeclRefExpr,hasExplicitTemplateArgs)18 AST_MATCHER(DeclRefExpr, hasExplicitTemplateArgs) {
19   return Node.hasExplicitTemplateArgs();
20 }
21 } // namespace
22 
23 namespace tidy::google::build {
24 
registerMatchers(ast_matchers::MatchFinder * Finder)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 
check(const MatchFinder::MatchResult & Result)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
69