[clang-tidy] Ignore instantiated functions and static data members of classes in misc-definitions-in-headers.

[alexfh]

LG

clang-tidy/misc/DefinitionsInHeadersCheck.cpp

void DefinitionsInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
 
   if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
     // Inline functions are allowed.
     if (FD->isInlined())
       return;
     // Function templates are allowed.
     if (FD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
       return;
-    // Function template full specialization is prohibited in header file.
-    if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
+    // Ignore instantiated functions.
+    if (FD->isTemplateInstantiation())
       return;
     // Member function of a class template and member function of a nested class
     // in a class template are allowed.
     if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
       const auto *DC = MD->getDeclContext();
       while (DC->isRecord()) {
         if (const auto *RD = dyn_cast<CXXRecordDecl>(DC)) {
           if (isa<ClassTemplatePartialSpecializationDecl>(RD))
diag(FD->getLocation(),
          "function %0 defined in a header file; "
          "function definitions in header files can lead to ODR violations")
         << FD << FixItHint::CreateInsertion(
                      FD->getReturnTypeSourceRange().getBegin(), "inline ");
   } else if (const auto *VD = dyn_cast<VarDecl>(ND)) {
     // Static data members of a class template are allowed.
     if (VD->getDeclContext()->isDependentContext() && VD->isStaticDataMember())
       return;
-    if (VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
+    // Ignore instantiated static data members of classes.
+    if (isTemplateInstantiation(VD->getTemplateSpecializationKind()))
       return;
     // Ignore variable definition within function scope.
     if (VD->hasLocalStorage() || VD->isStaticLocal())
       return;
 
     diag(VD->getLocation(),
          "variable %0 defined in a header file; "
          "variable definitions in header files can lead to ODR violations")
         << VD;
   }
 }
 
 } // namespace misc
 } // namespace tidy
 } // namespace clang

test/clang-tidy/misc-definitions-in-headers.hpp

 template <typename T>
 void CB<T>::CCB::f3() {
 // OK: member function definition of a nested class in a class template.
 }
 
 template <typename T>
 int CB<T>::a = 2; // OK: static data member definition of a class template.
 
+template class CB<int>; // OK: explicitly instantiated static data member of a class template.
+inline int callCB() {
+  CB<double> cb; // OK: implicitly instantiated static data member of a class template.
+  return cb.a;
+}
+
 template <typename T>
 T tf() { // OK: template function definition.
   T a;
   return a;
 }
 
 
 namespace NA {

 inline int f6() { return 1; } // OK: inline function definition.
 namespace {
   int f7() { return 1; }
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: function 'f7' defined in a header file;
 }
 
 int f8() = delete; // OK: the function being marked delete is not callable.
 
+template <typename T>
+int f9(T t) { return 1; }
+
+inline void callF9() { f9(1); } // OK: implicitly instantiated function.
+template int f9(double); // OK: explicitly instantiated function.
+
 int a = 1;
 // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: variable 'a' defined in a header file; variable definitions in header files can lead to ODR violations [misc-definitions-in-headers]
 CA a1;
 // CHECK-MESSAGES: :[[@LINE-1]]:4: warning: variable 'a1' defined in a header file;
 
 namespace NB {
   int b = 1;
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: variable 'b' defined in a header file;