fix(cpp1): emit parents' *template-head*s of alias

Author: JohelEGP

regression-tests/test-results/gcc-13/pure2-type-and-namespace-aliases.cpp.output

@@ -1,3 +0,0 @@
-pure2-type-and-namespace-aliases.cpp2:27:26: error: ‘template<class T> class myclass2’ used without template arguments
-   27 |     value: int == 42;
-      |                          ^

regression-tests/test-results/pure2-type-and-namespace-aliases.cpp

@@ -79,7 +79,7 @@ auto myfunc() -> void{
 }
 
 #line 27 "pure2-type-and-namespace-aliases.cpp2"
-    inline constexpr int myclass2::value = 42;
+    template <typename T> inline constexpr int myclass2<T>::value = 42;
 
 #line 30 "pure2-type-and-namespace-aliases.cpp2"
 auto main() -> int{

source/cppfront.cpp

@@ -4905,6 +4905,30 @@ class cppfront
     )
         -> void
     {
+        // Helper for declarations with parent *template-head*s.
+        auto const emit_parent_template_parameters = [&]() {
+            auto parent_template_parameters = std::string{};
+            auto parent = n.parent_declaration;
+            while (
+                parent
+                && parent->is_type()
+                )
+            {
+                if (parent->requires_clause_expression) {
+                    parent_template_parameters =
+                        "requires( " + print_to_string(*parent->requires_clause_expression) + " )\n"
+                        + parent_template_parameters;
+                }
+                if (parent->template_parameters) {
+                    parent_template_parameters =
+                        "template " + print_to_string( *parent->template_parameters, false, true )
+                        + " " + parent_template_parameters;
+                }
+                parent = parent->parent_declaration;
+            }
+            printer.print_cpp2(parent_template_parameters, n.position());
+        };
+
         //  Helper for declarations that can have requires-clauses
         auto const emit_requires_clause = [&]() {
             if (
@@ -5089,10 +5113,11 @@ class cppfront
                             );
                         }
                         else if (printer.get_phase() == printer.phase2_func_defs) {
+                            emit_parent_template_parameters();
                             printer.print_cpp2(
                                 "inline constexpr "
                                     + type + " "
-                                    + n.parent_declaration->name()->to_string() + "::"
+                                    + type_qualification_if_any_for(n)
                                     + print_to_string(*n.identifier)
                                     + " = "
                                     + print_to_string( *std::get<alias_node::an_object>(a->initializer) )
@@ -5260,26 +5285,7 @@ class cppfront
             && n.initializer    // only if the function has a definition (is not abstract)
             )
         {
-            auto parent_template_parameters = std::string{};
-            auto parent = n.parent_declaration;
-            while (
-                parent
-                && parent->is_type()
-                )
-            {
-                if (parent->requires_clause_expression) {
-                    parent_template_parameters =
-                        "requires( " + print_to_string(*parent->requires_clause_expression) + " )\n"
-                        + parent_template_parameters;
-                }
-                if (parent->template_parameters) {
-                    parent_template_parameters =
-                        "template " + print_to_string( *parent->template_parameters, false, true )
-                        + " " + parent_template_parameters;
-                }
-                parent = parent->parent_declaration;
-            }
-            printer.print_cpp2(parent_template_parameters, n.position());
+            emit_parent_template_parameters();
         }
 
         //  Now, emit our own template parameters