From e3d6fe72f8c7c79a09e18ba089552b7f6235c52b Mon Sep 17 00:00:00 2001
From: Louis Novy <101842021+louisnovy@users.noreply.github.com>
Date: Sun, 1 Mar 2026 20:58:43 -0800
Subject: [PATCH 1/3] fix broken bit_set parapoly specialization #6240

---
 src/check_expr.cpp   | 5 +++++
 src/check_type.cpp   | 1 +
 tests/issues/run.bat | 1 +
 tests/issues/run.sh  | 6 ++++++
 4 files changed, 13 insertions(+)

diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 1cf133f38..7f0acb4c6 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -1501,6 +1501,11 @@ gb_internal bool is_polymorphic_type_assignable(CheckerContext *c, Type *poly, T
 
 	case Type_BitSet:
 		if (source->kind == Type_BitSet) {
+			if (!is_type_polymorphic(poly->BitSet.elem)) {
+				if (poly->BitSet.upper != source->BitSet.upper || poly->BitSet.lower != source->BitSet.lower) {
+					return false;
+				}
+			}
 			if (!is_polymorphic_type_assignable(c, poly->BitSet.elem, source->BitSet.elem, true, modify_type)) {
 				return false;
 			}
diff --git a/src/check_type.cpp b/src/check_type.cpp
index b1d0045e9..82e70dd33 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -1229,6 +1229,7 @@ gb_internal void check_bit_set_type(CheckerContext *c, Type *type, Type *named_t
 	ast_node(bs, BitSetType, node);
 	GB_ASSERT(type->kind == Type_BitSet);
 	type->BitSet.node = node;
+	type->BitSet.elem = t_invalid;
 
 	/* i64 const DEFAULT_BITS = cast(i64)(8*build_context.word_size); */
 	i64 const MAX_BITS = 128;
diff --git a/tests/issues/run.bat b/tests/issues/run.bat
index f17f646a6..de380e313 100644
--- a/tests/issues/run.bat
+++ b/tests/issues/run.bat
@@ -29,6 +29,7 @@ set COMMON=-define:ODIN_TEST_FANCY=false -file -vet -strict-style -ignore-unused
 ..\..\..\odin test ..\test_issue_6068.odin %COMMON%  || exit /b
 ..\..\..\odin test ..\test_issue_6101.odin %COMMON%  || exit /b
 ..\..\..\odin test ..\test_issue_6165.odin %COMMON%  || exit /b
+..\..\..\odin build ..\test_issue_6240.odin %COMMON% 2>&1 | find /c "Error:" | findstr "3" || exit /b
 
 @echo off
 
diff --git a/tests/issues/run.sh b/tests/issues/run.sh
index 73d0d9587..6c6796e28 100755
--- a/tests/issues/run.sh
+++ b/tests/issues/run.sh
@@ -36,6 +36,12 @@ $ODIN test ../test_issue_5699.odin $COMMON
 $ODIN test ../test_issue_6068.odin $COMMON
 $ODIN test ../test_issue_6101.odin $COMMON
 $ODIN test ../test_issue_6165.odin $COMMON
+if [[ $($ODIN build ../test_issue_6240.odin $COMMON 2>&1 >/dev/null | grep -c "Error:") -eq 3 ]] ; then
+	echo "SUCCESSFUL 1/1"
+else
+	echo "SUCCESSFUL 0/1"
+	exit 1
+fi
 set +x
 
 popd

From 1a27af515f2dc431f7593b99d30a49a952486fbb Mon Sep 17 00:00:00 2001
From: Louis Novy <101842021+louisnovy@users.noreply.github.com>
Date: Sun, 1 Mar 2026 21:18:30 -0800
Subject: [PATCH 2/3] add test file

---
 tests/issues/test_issue_6240.odin | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 tests/issues/test_issue_6240.odin

diff --git a/tests/issues/test_issue_6240.odin b/tests/issues/test_issue_6240.odin
new file mode 100644
index 000000000..a56f44f33
--- /dev/null
+++ b/tests/issues/test_issue_6240.odin
@@ -0,0 +1,14 @@
+// Tests issue #6240 https://github.com/odin-lang/Odin/issues/6240
+package test_issues
+
+// should error - N=10 does not match bit_set range 0..<5
+foo :: proc($N: int, b: $B/bit_set[0 ..< N]) {}
+
+// should error without segfaulting - undefined identifier in bit_set range
+bar :: proc(b: $B/bit_set[0 ..< asdf]) {}
+
+main :: proc() {
+	b: bit_set[0 ..< 5]
+	foo(10, b)
+	bar(bit_set[0 ..< 1]{})
+}

From 7732a78c089a39722d9a43cc2cb206080ac028bf Mon Sep 17 00:00:00 2001
From: Louis Novy <101842021+louisnovy@users.noreply.github.com>
Date: Sun, 1 Mar 2026 21:33:14 -0800
Subject: [PATCH 3/3] harden run.bat and add missing test_issue_2395

---
 tests/issues/run.bat | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/issues/run.bat b/tests/issues/run.bat
index de380e313..9e722886d 100644
--- a/tests/issues/run.bat
+++ b/tests/issues/run.bat
@@ -21,6 +21,7 @@ set COMMON=-define:ODIN_TEST_FANCY=false -file -vet -strict-style -ignore-unused
 ..\..\..\odin test ..\test_issue_4210.odin %COMMON%  || exit /b
 ..\..\..\odin test ..\test_issue_4364.odin %COMMON%  || exit /b
 ..\..\..\odin test ..\test_issue_4584.odin %COMMON%  || exit /b
+..\..\..\odin build ..\test_issue_2395.odin %COMMON% 2>&1 | find /c "Error:" | findstr /x "2" || exit /b
 ..\..\..\odin build ..\test_issue_5043.odin %COMMON% || exit /b
 ..\..\..\odin build ..\test_issue_5097.odin %COMMON% || exit /b
 ..\..\..\odin build ..\test_issue_5097-2.odin %COMMON% || exit /b
@@ -29,7 +30,7 @@ set COMMON=-define:ODIN_TEST_FANCY=false -file -vet -strict-style -ignore-unused
 ..\..\..\odin test ..\test_issue_6068.odin %COMMON%  || exit /b
 ..\..\..\odin test ..\test_issue_6101.odin %COMMON%  || exit /b
 ..\..\..\odin test ..\test_issue_6165.odin %COMMON%  || exit /b
-..\..\..\odin build ..\test_issue_6240.odin %COMMON% 2>&1 | find /c "Error:" | findstr "3" || exit /b
+..\..\..\odin build ..\test_issue_6240.odin %COMMON% 2>&1 | find /c "Error:" | findstr /x "3" || exit /b
 
 @echo off