[clang-tools-extra] [clang-tidy] Add StrictMode to cppcoreguidelines-pro-type-static-cast-downcast (PR #69529)
Piotr Zegar via cfe-commits
cfe-commits at lists.llvm.org
Wed Oct 18 14:38:38 PDT 2023
https://github.com/PiotrZSL created https://github.com/llvm/llvm-project/pull/69529
Add StrictMode option that controls behavior whatever
warnings are emitted for casts on non-polymorphic types.
Fixes: #69414
>From 641a1daf6cd969a697c3cb4f0f7e168ca9187fe9 Mon Sep 17 00:00:00 2001
From: Piotr Zegar <me at piotrzegar.pl>
Date: Wed, 18 Oct 2023 21:35:37 +0000
Subject: [PATCH] [clang-tidy] Add StrictMode to
cppcoreguidelines-pro-type-static-cast-downcast
Add StrictMode option that controls behavior whatever
warnings are emitted for casts on non-polymorphic types.
---
.../ProTypeStaticCastDowncastCheck.cpp | 28 +++++++++----
.../ProTypeStaticCastDowncastCheck.h | 10 ++++-
clang-tools-extra/docs/ReleaseNotes.rst | 5 +++
.../pro-type-static-cast-downcast.rst | 8 ++++
.../pro-type-static-cast-downcast.cpp | 39 ++++++++++---------
5 files changed, 61 insertions(+), 29 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp
index 5344d465ad1fa71..2a89de27760febe 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.cpp
@@ -14,17 +14,24 @@ using namespace clang::ast_matchers;
namespace clang::tidy::cppcoreguidelines {
+ProTypeStaticCastDowncastCheck::ProTypeStaticCastDowncastCheck(
+ StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ StrictMode(Options.getLocalOrGlobal("StrictMode", true)) {}
+
+void ProTypeStaticCastDowncastCheck::storeOptions(
+ ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "StrictMode", StrictMode);
+}
+
void ProTypeStaticCastDowncastCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
- cxxStaticCastExpr(unless(isInTemplateInstantiation())).bind("cast"),
- this);
+ cxxStaticCastExpr(hasCastKind(CK_BaseToDerived)).bind("cast"), this);
}
void ProTypeStaticCastDowncastCheck::check(
const MatchFinder::MatchResult &Result) {
const auto *MatchedCast = Result.Nodes.getNodeAs<CXXStaticCastExpr>("cast");
- if (MatchedCast->getCastKind() != CK_BaseToDerived)
- return;
QualType SourceType = MatchedCast->getSubExpr()->getType();
const auto *SourceDecl = SourceType->getPointeeCXXRecordDecl();
@@ -33,15 +40,20 @@ void ProTypeStaticCastDowncastCheck::check(
if (!SourceDecl)
return;
- if (SourceDecl->isPolymorphic())
+ if (SourceDecl->isPolymorphic()) {
diag(MatchedCast->getOperatorLoc(),
"do not use static_cast to downcast from a base to a derived class; "
"use dynamic_cast instead")
<< FixItHint::CreateReplacement(MatchedCast->getOperatorLoc(),
"dynamic_cast");
- else
- diag(MatchedCast->getOperatorLoc(),
- "do not use static_cast to downcast from a base to a derived class");
+ return;
+ }
+
+ if (!StrictMode)
+ return;
+
+ diag(MatchedCast->getOperatorLoc(),
+ "do not use static_cast to downcast from a base to a derived class");
}
} // namespace clang::tidy::cppcoreguidelines
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.h
index 33ec8a071c10810..b9e78a82a39f2da 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeStaticCastDowncastCheck.h
@@ -20,13 +20,19 @@ namespace clang::tidy::cppcoreguidelines {
/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/pro-type-static-cast-downcast.html
class ProTypeStaticCastDowncastCheck : public ClangTidyCheck {
public:
- ProTypeStaticCastDowncastCheck(StringRef Name, ClangTidyContext *Context)
- : ClangTidyCheck(Name, Context) {}
+ ProTypeStaticCastDowncastCheck(StringRef Name, ClangTidyContext *Context);
bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
return LangOpts.CPlusPlus;
}
void registerMatchers(ast_matchers::MatchFinder *Finder) override;
void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+ std::optional<TraversalKind> getCheckTraversalKind() const override {
+ return TK_IgnoreUnlessSpelledInSource;
+ }
+
+private:
+ const bool StrictMode;
};
} // namespace clang::tidy::cppcoreguidelines
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 3e1fbe091c9ff6a..9dd25bd7cc61835 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -240,6 +240,11 @@ Changes in existing checks
<clang-tidy/checks/cppcoreguidelines/pro-type-member-init>` check to ignore
dependent delegate constructors.
+- Improved :doc:`cppcoreguidelines-pro-type-static-cast-downcast
+ <clang-tidy/checks/cppcoreguidelines/pro-type-static-cast-downcast>` check to
+ disregard casts on non-polymorphic types when the `StrictMode` option is set
+ to `false`.
+
- Improved :doc:`cppcoreguidelines-pro-type-vararg
<clang-tidy/checks/cppcoreguidelines/pro-type-vararg>` check to ignore
false-positives in unevaluated context (e.g., ``decltype``, ``sizeof``, ...).
diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-type-static-cast-downcast.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-type-static-cast-downcast.rst
index bcb353301f028a3..333e6db2aacec30 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-type-static-cast-downcast.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/pro-type-static-cast-downcast.rst
@@ -14,3 +14,11 @@ unrelated type ``Z``.
This rule is part of the `Type safety (Type.2)
<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Pro-type-downcast>`_
profile from the C++ Core Guidelines.
+
+Options
+-------
+
+.. option:: StrictMode
+
+ When set to `false`, no warnings are emitted for casts on non-polymorphic
+ types. Default is `true`.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-static-cast-downcast.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-static-cast-downcast.cpp
index 7a6c027ec479bab..11179b7d2d19b8f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-static-cast-downcast.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-static-cast-downcast.cpp
@@ -1,4 +1,5 @@
-// RUN: %check_clang_tidy %s cppcoreguidelines-pro-type-static-cast-downcast %t
+// RUN: %check_clang_tidy -check-suffixes=NSTRICT,STRICT %s cppcoreguidelines-pro-type-static-cast-downcast %t
+// RUN: %check_clang_tidy -check-suffix=NSTRICT %s cppcoreguidelines-pro-type-static-cast-downcast %t -- -config="{CheckOptions: {StrictMode: false}}"
class Base {
};
@@ -26,11 +27,11 @@ class PolymorphicMultiDerived : public Base, public PolymorphicBase {
void pointers() {
auto P0 = static_cast<Derived*>(new Base());
- // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-MESSAGES-STRICT: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
const Base* B0;
auto PC0 = static_cast<const Derived*>(B0);
- // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-MESSAGES-STRICT: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
auto P1 = static_cast<Base*>(new Derived()); // OK, upcast to a public base
auto P2 = static_cast<Base*>(new MultiDerived()); // OK, upcast to a public base
@@ -40,13 +41,13 @@ void pointers() {
void pointers_polymorphic() {
auto PP0 = static_cast<PolymorphicDerived*>(new PolymorphicBase());
- // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
- // CHECK-FIXES: auto PP0 = dynamic_cast<PolymorphicDerived*>(new PolymorphicBase());
+ // CHECK-MESSAGES-NSTRICT: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-FIXES-NSTRICT: auto PP0 = dynamic_cast<PolymorphicDerived*>(new PolymorphicBase());
const PolymorphicBase* B0;
auto PPC0 = static_cast<const PolymorphicDerived*>(B0);
- // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
- // CHECK-FIXES: auto PPC0 = dynamic_cast<const PolymorphicDerived*>(B0);
+ // CHECK-MESSAGES-NSTRICT: :[[@LINE-1]]:15: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-FIXES-NSTRICT: auto PPC0 = dynamic_cast<const PolymorphicDerived*>(B0);
auto B1 = static_cast<PolymorphicBase*>(new PolymorphicDerived()); // OK, upcast to a public base
@@ -57,27 +58,27 @@ void pointers_polymorphic() {
void arrays() {
Base ArrayOfBase[10];
auto A0 = static_cast<Derived*>(ArrayOfBase);
- // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-MESSAGES-STRICT: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
}
void arrays_polymorphic() {
PolymorphicBase ArrayOfPolymorphicBase[10];
auto AP0 = static_cast<PolymorphicDerived*>(ArrayOfPolymorphicBase);
- // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead
- // CHECK-FIXES: auto AP0 = dynamic_cast<PolymorphicDerived*>(ArrayOfPolymorphicBase);
+ // CHECK-MESSAGES-NSTRICT: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead
+ // CHECK-FIXES-NSTRICT: auto AP0 = dynamic_cast<PolymorphicDerived*>(ArrayOfPolymorphicBase);
}
void references() {
Base B0;
auto R0 = static_cast<Derived&>(B0);
- // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-MESSAGES-STRICT: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
Base& RefToBase = B0;
auto R1 = static_cast<Derived&>(RefToBase);
- // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-MESSAGES-STRICT: :[[@LINE-1]]:13: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
const Base& ConstRefToBase = B0;
auto RC1 = static_cast<const Derived&>(ConstRefToBase);
- // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-MESSAGES-STRICT: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class [cppcoreguidelines-pro-type-static-cast-downcast]
Derived RD1;
@@ -87,18 +88,18 @@ void references() {
void references_polymorphic() {
PolymorphicBase B0;
auto RP0 = static_cast<PolymorphicDerived&>(B0);
- // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead
- // CHECK-FIXES: auto RP0 = dynamic_cast<PolymorphicDerived&>(B0);
+ // CHECK-MESSAGES-NSTRICT: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead
+ // CHECK-FIXES-NSTRICT: auto RP0 = dynamic_cast<PolymorphicDerived&>(B0);
PolymorphicBase& RefToPolymorphicBase = B0;
auto RP1 = static_cast<PolymorphicDerived&>(RefToPolymorphicBase);
- // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
- // CHECK-FIXES: auto RP1 = dynamic_cast<PolymorphicDerived&>(RefToPolymorphicBase);
+ // CHECK-MESSAGES-NSTRICT: :[[@LINE-1]]:14: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-FIXES-NSTRICT: auto RP1 = dynamic_cast<PolymorphicDerived&>(RefToPolymorphicBase);
const PolymorphicBase& ConstRefToPolymorphicBase = B0;
auto RPC2 = static_cast<const PolymorphicDerived&>(ConstRefToPolymorphicBase);
- // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
- // CHECK-FIXES: auto RPC2 = dynamic_cast<const PolymorphicDerived&>(ConstRefToPolymorphicBase);
+ // CHECK-MESSAGES-NSTRICT: :[[@LINE-1]]:15: warning: do not use static_cast to downcast from a base to a derived class; use dynamic_cast instead [cppcoreguidelines-pro-type-static-cast-downcast]
+ // CHECK-FIXES-NSTRICT: auto RPC2 = dynamic_cast<const PolymorphicDerived&>(ConstRefToPolymorphicBase);
PolymorphicDerived d1;
auto RP2 = static_cast<PolymorphicBase&>(d1); // OK, upcast to a public base
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