From 4538a1f50daee6a55d65aa0ee512c1aabf852b12 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Wed, 26 Mar 2025 18:04:00 +0100
Subject: [PATCH] - Correctly errors when a generic module contains a
 self-generic type.

---
 lib/std/collections/map.c3                  |  0
 releasenotes.md                             |  1 +
 src/compiler/sema_decls.c                   |  7 +++++
 test/test_suite/generic/generic_self_ref.c3 | 29 +++++++++++++++++++++
 4 files changed, 37 insertions(+)
 delete mode 100644 lib/std/collections/map.c3
 create mode 100644 test/test_suite/generic/generic_self_ref.c3

diff --git a/lib/std/collections/map.c3 b/lib/std/collections/map.c3
deleted file mode 100644
index e69de29bb..000000000
diff --git a/releasenotes.md b/releasenotes.md
index 76d5fefe6..0c0bc583c 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -60,6 +60,7 @@
 - Incorrectly allowed getting pointer to a macro #2049.
 - &self not runtime null-checked in macro #1827.
 - Bug when printing a boolean value as an integer using printf.
+- Show error when a generic module contains a self-generic type.
 
 ### Stdlib changes
 - `new_*` functions in general moved to version without `new_` prefix.
diff --git a/src/compiler/sema_decls.c b/src/compiler/sema_decls.c
index 8005c1d60..f8c102605 100755
--- a/src/compiler/sema_decls.c
+++ b/src/compiler/sema_decls.c
@@ -4497,6 +4497,13 @@ Decl *sema_analyse_parameterized_identifier(SemaContext *c, Path *decl_path, con
 	Decl *alias = name_resolve.found;
 	ASSERT(alias);
 	Module *module = alias->unit->module;
+
+	if (c->unit->module->generic_module == module)
+	{
+		sema_error_at(c, span, "This identifier is recursively using %s.", module->name->module);
+		return poisoned_decl;
+	}
+
 	unsigned parameter_count = vec_size(module->parameters);
 	ASSERT(parameter_count > 0);
 	if (parameter_count != vec_size(params))
diff --git a/test/test_suite/generic/generic_self_ref.c3 b/test/test_suite/generic/generic_self_ref.c3
new file mode 100644
index 000000000..7a8f1ea84
--- /dev/null
+++ b/test/test_suite/generic/generic_self_ref.c3
@@ -0,0 +1,29 @@
+module gui::widget {Type};
+import gui::widget_types;
+import std::collections::list;
+import std::io;
+
+struct Widget
+{
+	int id;
+	Type type;
+	List {any} children;
+}
+
+fn void Widget{Label}.draw(Widget* self) // #error: This identifier is recursively using gui::widget
+{
+	io::printfn("Hello Label");
+}
+
+module gui::widget_types;
+import gui::widget;
+struct Label
+{
+	String text;
+}
+
+fn void main()
+{
+	Widget {int} y;
+	y.draw();
+}
\ No newline at end of file