1 //===--- ProTypeStaticCastDowncastCheck.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 "ProTypeStaticCastDowncastCheck.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::cppcoreguidelines {
16
ProTypeStaticCastDowncastCheck(StringRef Name,ClangTidyContext * Context)17 ProTypeStaticCastDowncastCheck::ProTypeStaticCastDowncastCheck(
18 StringRef Name, ClangTidyContext *Context)
19 : ClangTidyCheck(Name, Context),
20 StrictMode(Options.getLocalOrGlobal("StrictMode", true)) {}
21
storeOptions(ClangTidyOptions::OptionMap & Opts)22 void ProTypeStaticCastDowncastCheck::storeOptions(
23 ClangTidyOptions::OptionMap &Opts) {
24 Options.store(Opts, "StrictMode", StrictMode);
25 }
26
registerMatchers(MatchFinder * Finder)27 void ProTypeStaticCastDowncastCheck::registerMatchers(MatchFinder *Finder) {
28 Finder->addMatcher(
29 cxxStaticCastExpr(hasCastKind(CK_BaseToDerived)).bind("cast"), this);
30 }
31
check(const MatchFinder::MatchResult & Result)32 void ProTypeStaticCastDowncastCheck::check(
33 const MatchFinder::MatchResult &Result) {
34 const auto *MatchedCast = Result.Nodes.getNodeAs<CXXStaticCastExpr>("cast");
35
36 QualType SourceType = MatchedCast->getSubExpr()->getType();
37 const auto *SourceDecl = SourceType->getPointeeCXXRecordDecl();
38 if (!SourceDecl) // The cast is from object to reference
39 SourceDecl = SourceType->getAsCXXRecordDecl();
40 if (!SourceDecl)
41 return;
42
43 if (SourceDecl->isPolymorphic()) {
44 diag(MatchedCast->getOperatorLoc(),
45 "do not use static_cast to downcast from a base to a derived class; "
46 "use dynamic_cast instead")
47 << FixItHint::CreateReplacement(MatchedCast->getOperatorLoc(),
48 "dynamic_cast");
49 return;
50 }
51
52 if (!StrictMode)
53 return;
54
55 diag(MatchedCast->getOperatorLoc(),
56 "do not use static_cast to downcast from a base to a derived class");
57 }
58
59 } // namespace clang::tidy::cppcoreguidelines
60