fix(cpp1): emit template template parameters

regression-tests/pure2-bugfix-for-template-template-parameter.cpp2

@@ -0,0 +1,5 @@
+t: @struct <T: <_, _: _>> type = { }
+
+u: @struct <T, V: _> type = { }
+
+main: () = { _ = :t<u> = (); }

regression-tests/test-results/clang-18/clang-version.output

@@ -0,0 +1,4 @@
+clang version 18.0.0 (https://github.com/llvm/llvm-project.git 3723ede3cf5324827f8fbbe7f484c2ee4d7a7204)
+Target: x86_64-pc-linux-gnu
+Thread model: posix
+InstalledDir: /home/johel/root/clang-main/bin

regression-tests/test-results/clang-18/pure2-union.cpp.execution

@@ -0,0 +1,3 @@
+sizeof(x) is 25
+(not a name)
+xyz

regression-tests/test-results/pure2-bugfix-for-template-template-parameter.cpp

@@ -0,0 +1,28 @@
+
+#define CPP2_USE_MODULES         Yes
+
+//=== Cpp2 type declarations ====================================================
+
+
+#include "cpp2util.h"
+
+template<template <typename , auto> class T> class t;
+
+template<typename T, auto V> class u;
+
+
+//=== Cpp2 type definitions and function declarations ===========================
+
+template<template <typename , auto> class T> class t {};
+
+template<typename T, auto V> class u {};
+
+auto main() -> int;
+
+
+//=== Cpp2 function definitions =================================================
+
+
+#line 5 "pure2-bugfix-for-template-template-parameter.cpp2"
+auto main() -> int{static_cast<void>(t<u>{}); }
+

regression-tests/test-results/pure2-bugfix-for-template-template-parameter.cpp2.output

@@ -0,0 +1,2 @@
+pure2-bugfix-for-template-template-parameter.cpp2... ok (all Cpp2, passes safety checks)
+

source/cppfront.cpp

@@ -3842,7 +3842,8 @@ class cppfront
     auto emit(
         parameter_declaration_node const& n,
         bool                              is_returns            = false,
-        bool                              is_template_parameter = false
+        bool                              is_template_parameter = false,
+        bool                              emit_identifier       = true
     )
         -> void
     {
@@ -3925,15 +3926,32 @@ class cppfront
         //  Handle type parameters
 
         if (n.declaration->is_type()) {
+            assert (n.declaration->identifier);
             printer.print_cpp2("typename ", n.declaration->identifier->position());
             if (n.declaration->is_variadic) {
                 printer.print_cpp2(
                     "...",
                     n.declaration->identifier->position()
                 );
             }
+            if (emit_identifier) {
+                emit(*n.declaration->identifier);
+            }
+            return;
+        }
+
+        //-----------------------------------------------------------------------
+        //  Handle template parameters
+
+        if (n.declaration->is_template()) {
             assert (n.declaration->identifier);
-            emit(*n.declaration->identifier);
+            printer.print_cpp2("template ", n.declaration->identifier->position());
+            emit(*n.declaration->template_parameters, is_returns, true, false);
+            printer.print_cpp2(" class", n.declaration->identifier->position());
+            if (emit_identifier) {
+                printer.print_cpp2(" ", n.declaration->identifier->position());
+                emit(*n.declaration->identifier);
+            }
             return;
         }
 
@@ -3945,9 +3963,11 @@ class cppfront
 
         if (is_template_parameter) {
             emit( type_id );
-            printer.print_cpp2(" ", type_id.position());
-            assert (n.declaration->identifier);
-            emit(*n.declaration->identifier);
+            if (emit_identifier) {
+                printer.print_cpp2(" ", type_id.position());
+                assert (n.declaration->identifier);
+                emit(*n.declaration->identifier);
+            }
             return;
         }
 
@@ -4149,7 +4169,8 @@ class cppfront
     auto emit(
         parameter_declaration_list_node const& n,
         bool                                   is_returns            = false,
-        bool                                   is_template_parameter = false
+        bool                                   is_template_parameter = false,
+        bool                                   emit_identifier       = true
     )
         -> void
     {
@@ -4177,7 +4198,7 @@ class cppfront
             }
             prev_pos = x->position();
             assert(x);
-            emit(*x, is_returns, is_template_parameter);
+            emit(*x, is_returns, is_template_parameter, emit_identifier);
             if (!x->declaration->has_name("this")) {
                 first = false;
             }

source/parse.h

@@ -2740,6 +2740,8 @@ struct declaration_node
 
     auto is_function_expression () const -> bool
         { return is_function() && !identifier;  }
+    auto is_template() const -> bool
+        { return template_parameters != nullptr; }
 
     auto is_polymorphic() const // has base types or virtual functions
         -> bool