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 {
24 namespace google {
25 namespace build {
26
registerMatchers(ast_matchers::MatchFinder * Finder)27 void ExplicitMakePairCheck::registerMatchers(
28 ast_matchers::MatchFinder *Finder) {
29 // Only register the matchers for C++; the functionality currently does not
30 // provide any benefit to other languages, despite being benign.
31 if (!getLangOpts().CPlusPlus)
32 return;
33
34 // Look for std::make_pair with explicit template args. Ignore calls in
35 // templates.
36 Finder->addMatcher(
37 callExpr(unless(isInTemplateInstantiation()),
38 callee(expr(ignoringParenImpCasts(
39 declRefExpr(hasExplicitTemplateArgs(),
40 to(functionDecl(hasName("::std::make_pair"))))
41 .bind("declref")))))
42 .bind("call"),
43 this);
44 }
45
check(const MatchFinder::MatchResult & Result)46 void ExplicitMakePairCheck::check(const MatchFinder::MatchResult &Result) {
47 const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
48 const auto *DeclRef = Result.Nodes.getNodeAs<DeclRefExpr>("declref");
49
50 // Sanity check: The use might have overriden ::std::make_pair.
51 if (Call->getNumArgs() != 2)
52 return;
53
54 const Expr *Arg0 = Call->getArg(0)->IgnoreParenImpCasts();
55 const Expr *Arg1 = Call->getArg(1)->IgnoreParenImpCasts();
56
57 // If types don't match, we suggest replacing with std::pair and explicit
58 // template arguments. Otherwise just remove the template arguments from
59 // make_pair.
60 if (Arg0->getType() != Call->getArg(0)->getType() ||
61 Arg1->getType() != Call->getArg(1)->getType()) {
62 diag(Call->getBeginLoc(), "for C++11-compatibility, use pair directly")
63 << FixItHint::CreateReplacement(
64 SourceRange(DeclRef->getBeginLoc(), DeclRef->getLAngleLoc()),
65 "std::pair<");
66 } else {
67 diag(Call->getBeginLoc(),
68 "for C++11-compatibility, omit template arguments from make_pair")
69 << FixItHint::CreateRemoval(
70 SourceRange(DeclRef->getLAngleLoc(), DeclRef->getRAngleLoc()));
71 }
72 }
73
74 } // namespace build
75 } // namespace google
76 } // namespace tidy
77 } // namespace clang
78