From 0da9721c9fac4ad2221e49e7b5a5075ccce04526 Mon Sep 17 00:00:00 2001
From: hyung-hwan <hyunghwan.chung@gmail.com>
Date: Tue, 16 Sep 2025 23:47:50 +0900
Subject: [PATCH] enhanced class_enter to check indexed type between a class
 and a superclass

---
 lib/exec.c       | 14 ++++++++++++++
 lib/hak.c        | 12 ++++++++++++
 lib/hak.h        |  4 ++++
 t/class-5001.err | 25 +++++++++++++++++++++++++
 4 files changed, 55 insertions(+)

diff --git a/lib/exec.c b/lib/exec.c
index fab005a..5d0602f 100644
--- a/lib/exec.c
+++ b/lib/exec.c
@@ -4122,6 +4122,9 @@ static int execute (hak_t* hak)
 
 				if (b1 > 0)
 				{
+					hak_ooi_t super_spec;
+					hak_obj_type_t super_indexed_type;
+
 					HAK_STACK_POP_TO(hak, superclass); /* TODO: support more than 1 superclass later when the compiler supports more */
 					if (!HAK_IS_CLASS(hak, superclass))
 					{
@@ -4129,6 +4132,17 @@ static int execute (hak_t* hak)
 						if (do_throw_with_internal_errmsg(hak, fetched_instruction_pointer) >= 0) break;
 						goto oops_with_errmsg_supplement;
 					}
+
+					super_spec = HAK_OOP_TO_SMOOI(((hak_oop_class_t)superclass)->spec);
+					super_indexed_type = HAK_CLASS_SPEC_INDEXED_TYPE(super_spec);
+					if (super_indexed_type != b5)
+					{
+						/* TODO: include the class indexed type in the message .. */
+						hak_seterrbfmt(hak, HAK_ECALL, "incompatible %hs superclass %O with %hs class",
+							hak_obj_type_to_bcstr(super_indexed_type), superclass, hak_obj_type_to_bcstr(b5));
+						if (do_throw_with_internal_errmsg(hak, fetched_instruction_pointer) >= 0) break;
+						goto oops_with_errmsg_supplement;
+					}
  				}
 				else superclass = hak->_nil;
 
diff --git a/lib/hak.c b/lib/hak.c
index 9fadb2f..664371e 100644
--- a/lib/hak.c
+++ b/lib/hak.c
@@ -1017,3 +1017,15 @@ hak_pfbase_t* hak_findpfbase (hak_t* hak, hak_pfinfo_t* pfinfo, hak_oow_t pfcoun
 	return HAK_NULL;
 }
 
+const hak_bch_t* hak_obj_type_to_bcstr (hak_obj_type_t type)
+{
+	static const hak_bch_t* names[] = {
+		"oop",
+		"char",
+		"byte",
+		"halfword",
+		"word",
+	};
+
+	return (type < HAK_COUNTOF(names))? names[type]: "";
+}
diff --git a/lib/hak.h b/lib/hak.h
index e2ad2bc..abaf5f6 100644
--- a/lib/hak.h
+++ b/lib/hak.h
@@ -2097,6 +2097,10 @@ typedef int (*hak_xchg_writer_t) (
 extern "C" {
 #endif
 
+HAK_EXPORT const hak_bch_t* hak_obj_type_to_bcstr (
+	hak_obj_type_t type
+);
+
 HAK_EXPORT hak_t* hak_open (
 	hak_mmgr_t*         mmgr,
 	hak_oow_t           xtnsize,
diff --git a/t/class-5001.err b/t/class-5001.err
index 3e116dc..bca0f24 100644
--- a/t/class-5001.err
+++ b/t/class-5001.err
@@ -321,3 +321,28 @@ class Kuduro (a (b) c) {
 	var d e
 	var(#class) b ##ERROR: syntax error - duplicate class variable name 'b'
 }
+
+---
+
+## TODO: some of these can be detected as an error at the compile time..
+
+class[#b] X (a) {
+	fun[#ci] new() {
+		## the instance variable is a byte because the class is a byte-oriented class
+		self.a := -20 ##ERROR: exception not handled - "negative number - -20"
+	}
+}
+
+X:new
+
+---
+
+class[#b] X (a) {
+	fun[#ci] new() {
+		## the instance variable is a byte because the class is a byte-oriented class
+		self.a := -20 ##ERROR: exception not handled - "negative number - -20"
+	}
+}
+
+class Y: X { ##ERROR: exception not handled - "incompatible byte superclass X with oop class"
+}