From 69aee1243f517cb1102e4041e2490f9429c45f81 Mon Sep 17 00:00:00 2001
From: Christian Menard <christian.menard@tu-dresden.de>
Date: Tue, 14 May 2024 14:28:01 +0200
Subject: [PATCH] Fixed code generation for nested generic reactor instances

---
 .../generator/cpp/CppInstanceGenerator.kt     |  2 +-
 test/Cpp/src/target/GenericComposition.lf     | 33 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 test/Cpp/src/target/GenericComposition.lf

diff --git a/core/src/main/kotlin/org/lflang/generator/cpp/CppInstanceGenerator.kt b/core/src/main/kotlin/org/lflang/generator/cpp/CppInstanceGenerator.kt
index d734827252..32f6004f22 100644
--- a/core/src/main/kotlin/org/lflang/generator/cpp/CppInstanceGenerator.kt
+++ b/core/src/main/kotlin/org/lflang/generator/cpp/CppInstanceGenerator.kt
@@ -103,7 +103,7 @@ class CppInstanceGenerator(
         // by iterating over the reactor parameters we make sure that the parameters are assigned in declaration order
         return reactor.parameters.mapNotNull {
             if (it.name in assignments) ".${it.name} = ${assignments[it.name]}" else null
-        }.joinToString(", ", "$reactorType::Parameters{", "}")
+        }.joinToString(", ", "typename $reactorType::Parameters{", "}")
     }
 
     private fun generateInitializer(inst: Instantiation): String? = with(inst) {
diff --git a/test/Cpp/src/target/GenericComposition.lf b/test/Cpp/src/target/GenericComposition.lf
new file mode 100644
index 0000000000..4c4083240a
--- /dev/null
+++ b/test/Cpp/src/target/GenericComposition.lf
@@ -0,0 +1,33 @@
+target Cpp {
+  timeout: 1 sec
+}
+
+reactor Counter<T> {
+  state count: T(0)
+  timer t(0, 1 sec)
+  output out: T
+
+  reaction(t) -> out {=
+    out.set(count);
+    count += 1;
+  =}
+}
+
+reactor Printer<T> {
+  input in: T
+
+  reaction(in) {=
+    auto msg = *in.get();
+    std::cout << msg << std::endl;
+  =}
+}
+
+reactor MyWrapper<T> {
+  c = new Counter<T>()
+  p = new Printer<T>()
+  c.out -> p.in
+}
+
+main reactor {
+  m = new MyWrapper<int>()
+}