[clang-tidy] Fix misc-definitions-in-headers misplaced fixing to fully templated function.

[hokein]

@aaron.ballman, could you take a look on this patch? Alex is on vocation these days.

[aaron.ballman]

Patch LGTM, thank you!

clang-tidy/misc/DefinitionsInHeadersCheck.cpp

if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
         }
         DC = DC->getParent();
       }
     }
 
     diag(FD->getLocation(),
          "function %0 defined in a header file; "
          "function definitions in header files can lead to ODR violations")
-        << FD << FixItHint::CreateInsertion(FD->getSourceRange().getBegin(),
-                                            "inline ");
+        << 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)
       return;
     // Ignore variable definition within function scope.
     if (VD->hasLocalStorage() || VD->isStaticLocal())

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

 
 void CA::f2() { }
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: function 'f2' defined in a header file;
 // CHECK-FIXES: inline void CA::f2() {
 
 template <>
 int CA::f3() {
 // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: function 'f3<int>' defined in a header file;
+// CHECK-FIXES: inline int CA::f3() {
   int a = 1;
   return a;
 }
 
 template <typename T>
 void CA::CAA<T>::CAB::f4() {
 // OK: member function definition of a nested template class in a class.
 }

 
 template <typename T>
 T f3() {
   T a = 1;
   return a;
 }
 
 template <>
-// CHECK-MESSAGES: :[[@LINE+1]]:5: warning: function 'f3<int>' defined in a header file;
 int f3() {
+// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: function 'f3<int>' defined in a header file;
+// CHECK-FIXES: inline int f3() {
   int a = 1;
   return a;
 }
 
 int f5(); // OK: function declaration.
 inline int f6() { return 1; } // OK: inline function definition.
 namespace {
   int f7() { return 1; }

 
 template <>
 struct CD<int, int> {
   int f();
 };
 
 int CD<int, int>::f() {
 // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: function 'f' defined in a header file;
+// CHECK-FIXES: inline int CD<int, int>::f() {
   return 0;
 }
 
 template <typename T>
 int CD<T, int>::f() { // OK: partial template specialization.
   return 0;
 }