clang-tools-extra/clang-tidy/bugprone/IncorrectEnableIfCheck.cpp

   1 //===--- IncorrectEnableIfCheck.cpp - clang-tidy --------------------------===//
   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 "IncorrectEnableIfCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12
  13 using namespace clang::ast_matchers;
  14
  15 namespace clang::tidy::bugprone {
  16
  17 namespace {
  18
  19 AST_MATCHER_P(TemplateTypeParmDecl, hasUnnamedDefaultArgument,
  20               ast_matchers::internal::Matcher<TypeLoc>, InnerMatcher) {
  21   if (Node.getIdentifier() != nullptr || !Node.hasDefaultArgument() ||
  22       Node.getDefaultArgumentInfo() == nullptr)
  23     return false;
  24
  25   TypeLoc DefaultArgTypeLoc = Node.getDefaultArgumentInfo()->getTypeLoc();
  26   return InnerMatcher.matches(DefaultArgTypeLoc, Finder, Builder);
  27 }
  28
  29 } // namespace
  30
  31 void IncorrectEnableIfCheck::registerMatchers(MatchFinder *Finder) {
  32   Finder->addMatcher(
  33       templateTypeParmDecl(
  34           hasUnnamedDefaultArgument(
  35               elaboratedTypeLoc(
  36                   hasNamedTypeLoc(templateSpecializationTypeLoc(
  37                                       loc(qualType(hasDeclaration(namedDecl(
  38                                           hasName("::std::enable_if"))))))
  39                                       .bind("enable_if_specialization")))
  40                   .bind("elaborated")))
  41           .bind("enable_if"),
  42       this);
  43 }
  44
  45 void IncorrectEnableIfCheck::check(const MatchFinder::MatchResult &Result) {
  46   const auto *EnableIf =
  47       Result.Nodes.getNodeAs<TemplateTypeParmDecl>("enable_if");
  48   const auto *ElaboratedLoc =
  49       Result.Nodes.getNodeAs<ElaboratedTypeLoc>("elaborated");
  50   const auto *EnableIfSpecializationLoc =
  51       Result.Nodes.getNodeAs<TemplateSpecializationTypeLoc>(
  52           "enable_if_specialization");
  53
  54   if (!EnableIf || !ElaboratedLoc || !EnableIfSpecializationLoc)
  55     return;
  56
  57   const SourceManager &SM = *Result.SourceManager;
  58   SourceLocation RAngleLoc =
  59       SM.getExpansionLoc(EnableIfSpecializationLoc->getRAngleLoc());
  60
  61   auto Diag = diag(EnableIf->getBeginLoc(),
  62                    "incorrect std::enable_if usage detected; use "
  63                    "'typename std::enable_if<...>::type'");
  64   if (!getLangOpts().CPlusPlus20) {
  65     Diag << FixItHint::CreateInsertion(ElaboratedLoc->getBeginLoc(),
  66                                        "typename ");
  67   }
  68   Diag << FixItHint::CreateInsertion(RAngleLoc.getLocWithOffset(1), "::type");
  69 }
  70
  71 } // namespace clang::tidy::bugprone