[clang-tidy] ppcoreguidelines-pro-type-member-init: suppress warning for default member funcs

[cwarner-8702]

Summary

Modify the cppcoreguidelines-pro-type-member-init checker to ignore warnings from the move and copy-constructors when they are compiler defined with = default outside of the type declaration.

Reported as LLVM bug 36819

[malcolm.parsons]

LGTM

[cwarner-8702]

@malcolm.parsons Could you or someone with commit access merge this on my behalf?

Author Name: Chris Warner
Author Email: [e-mail]

clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp

Finder->addMatcher(
       this);
 }
 
 void ProTypeMemberInitCheck::check(const MatchFinder::MatchResult &Result) {
   if (const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor")) {
     // Skip declarations delayed by late template parsing without a body.
     if (!Ctor->getBody())
       return;
+    // Skip out-of-band explicitly defaulted special member functions
+    // (except the default constructor).
+    if (Ctor->isExplicitlyDefaulted() && !Ctor->isDefaultConstructor())
+      return;
     checkMissingMemberInitializer(*Result.Context, *Ctor->getParent(), Ctor);
     checkMissingBaseClassInitializer(*Result.Context, *Ctor->getParent(), Ctor);
   } else if (const auto *Record =
                  Result.Nodes.getNodeAs<CXXRecordDecl>("record")) {
     assert(Record->hasDefaultConstructor() &&
            "Matched record should have a default constructor");
     checkMissingMemberInitializer(*Result.Context, *Record, nullptr);
     checkMissingBaseClassInitializer(*Result.Context, *Record, nullptr);

clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-pro-type-member-init.cpp

 
 struct NegativeImplicitInheritedCtor : NegativeImplicitInheritedCtorBase {
   using NegativeImplicitInheritedCtorBase::NegativeImplicitInheritedCtorBase;
 };
 
 void Bug33557() {
   NegativeImplicitInheritedCtor I(5);
 }
+
+struct NegativeDefaultedCtorOutOfDecl {
+  NegativeDefaultedCtorOutOfDecl(const NegativeDefaultedCtorOutOfDecl &);
+  int F;
+};
+
+NegativeDefaultedCtorOutOfDecl::NegativeDefaultedCtorOutOfDecl(const NegativeDefaultedCtorOutOfDecl &) = default;
+
+struct PositiveDefaultConstructorOutOfDecl {
+  PositiveDefaultConstructorOutOfDecl();
+  int F;
+  // CHECK-FIXES: int F{};
+};
+
+PositiveDefaultConstructorOutOfDecl::PositiveDefaultConstructorOutOfDecl() = default;
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: constructor does not initialize these fields: F