refactor: fix condition to not emit forward declaration of specialization

Author: JohelEGP

regression-tests/test-results/pure2-template-specialization.cpp

@@ -8,8 +8,7 @@
 
 #line 1 "pure2-template-specialization.cpp2"
 template   <typename T> class t;
-template<typename T> requires( true )
-class t<T>;
+
 
 //=== Cpp2 type definitions and function declarations ===========================
 

source/cppfront.cpp

@@ -4885,9 +4885,13 @@ class cppfront
 
         if (
             printer.get_phase() == printer.phase0_type_decls
-            && !n.is_namespace()
-            && !n.is_type()
-            && n.specialization_template_arguments == nullptr
+            && (
+                (
+                 !n.is_namespace()
+                 && !n.is_type()
+                 ) ||
+                     n.is_specialization()
+                )
             )
         {
             return;

source/parse.h

@@ -2599,6 +2599,9 @@ struct declaration_node
     auto is_alias() const -> bool
         { return type.index() == an_alias;    }
 
+    auto is_specialization() const -> bool
+        { return specialization_template_arguments != nullptr;    }
+
     auto is_polymorphic() const // has base types or virtual functions
         -> bool
     {