1 //===--- AvoidNestedConditionalOperatorCheck.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 "AvoidNestedConditionalOperatorCheck.h"
10 #include "clang/ASTMatchers/ASTMatchFinder.h"
11 #include "clang/ASTMatchers/ASTMatchers.h"
12 #include "clang/Basic/DiagnosticIDs.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang::tidy::readability {
17 
registerMatchers(MatchFinder * Finder)18 void AvoidNestedConditionalOperatorCheck::registerMatchers(
19     MatchFinder *Finder) {
20   Finder->addMatcher(
21       conditionalOperator(
22           anyOf(
23               hasCondition(ignoringParenCasts(
24                   conditionalOperator().bind("nested-conditional-operator"))),
25               hasTrueExpression(ignoringParenCasts(
26                   conditionalOperator().bind("nested-conditional-operator"))),
27               hasFalseExpression(ignoringParenCasts(
28                   conditionalOperator().bind("nested-conditional-operator")))))
29           .bind("conditional-operator"),
30       this);
31 }
32 
check(const MatchFinder::MatchResult & Result)33 void AvoidNestedConditionalOperatorCheck::check(
34     const MatchFinder::MatchResult &Result) {
35   const auto *CO =
36       Result.Nodes.getNodeAs<ConditionalOperator>("conditional-operator");
37   const auto *NCO = Result.Nodes.getNodeAs<ConditionalOperator>(
38       "nested-conditional-operator");
39   assert(CO);
40   assert(NCO);
41 
42   if (CO->getBeginLoc().isMacroID() || NCO->getBeginLoc().isMacroID())
43     return;
44 
45   diag(NCO->getBeginLoc(),
46        "conditional operator is used as sub-expression of parent conditional "
47        "operator, refrain from using nested conditional operators");
48   diag(CO->getBeginLoc(), "parent conditional operator here",
49        DiagnosticIDs::Note);
50 }
51 
52 } // namespace clang::tidy::readability
53