From cf0a04977a9cd42be99e1ddd8e77aca7a7c8e1dd Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Wed, 22 Dec 2021 01:03:15 +0100
Subject: [PATCH] Prevent circular initializers.

---
 src/compiler/sema_expr.c                      | 19 ++++++++++++++++++-
 test/test_suite/globals/recursive_globals.c3  |  3 +++
 .../globals/self_referencing_local.c3         |  5 +++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 test/test_suite/globals/recursive_globals.c3
 create mode 100644 test/test_suite/globals/self_referencing_local.c3

diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index a50da2421..a7928bdad 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -640,6 +640,22 @@ static inline bool sema_cast_ident_rvalue(Context *context, Expr *expr)
 			UNREACHABLE
 	}
 	switch (decl->var.kind)
+	{
+		case VARDECL_CONST:
+		case VARDECL_GLOBAL:
+		case VARDECL_LOCAL:
+		case VARDECL_LOCAL_CT:
+		case VARDECL_LOCAL_CT_TYPE:
+			if (decl->var.init_expr && decl->var.init_expr->resolve_status != RESOLVE_DONE)
+			{
+				SEMA_ERROR(expr, "This looks like the initialization of the variable was circular.");
+				return false;
+			}
+			break;
+		default:
+			break;
+	}
+	switch (decl->var.kind)
 	{
 		case VARDECL_CONST:
 			if (!expr_is_constant_eval(decl->var.init_expr, CONSTANT_EVAL_ANY))
@@ -7118,7 +7134,8 @@ bool sema_analyse_inferred_expr(Context *context, Type *infer_type, Expr *expr)
 			if (!sema_analyse_expr_dispatch(context, expr)) return expr_poison(expr);
 			break;
 	}
+	if (!sema_cast_rvalue(context, expr)) return false;
 	expr->resolve_status = RESOLVE_DONE;
-	return sema_cast_rvalue(context, expr);
+	return true;
 }
 
diff --git a/test/test_suite/globals/recursive_globals.c3 b/test/test_suite/globals/recursive_globals.c3
new file mode 100644
index 000000000..d6d2a725f
--- /dev/null
+++ b/test/test_suite/globals/recursive_globals.c3
@@ -0,0 +1,3 @@
+void *x = &x;
+
+int y = 1 + y; // #error: This looks like the initialization of the variable was circular.
\ No newline at end of file
diff --git a/test/test_suite/globals/self_referencing_local.c3 b/test/test_suite/globals/self_referencing_local.c3
new file mode 100644
index 000000000..6da61b7a8
--- /dev/null
+++ b/test/test_suite/globals/self_referencing_local.c3
@@ -0,0 +1,5 @@
+fn void test()
+{
+    void* x = &x;
+    int y = y; // #error: This looks like the initialization of the variable was circular.
+}
\ No newline at end of file