From 9436efe55432799220e105247d0f6a0b7a37ea38 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Mon, 20 May 2024 14:42:09 +0200
Subject: [PATCH] Compiler crash on designated initializer for structs with
 bitstruct.

---
 releasenotes.md                               |  1 +
 src/compiler/llvm_codegen_expr.c              |  6 +--
 .../bitstruct/bitstruct_direct_in_struct.c3t  | 38 +++++++++++++++++++
 3 files changed, 42 insertions(+), 3 deletions(-)
 create mode 100644 test/test_suite/bitstruct/bitstruct_direct_in_struct.c3t

diff --git a/releasenotes.md b/releasenotes.md
index 27eab7527..a07bc66f1 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -21,6 +21,7 @@
 - Assertion failed when casting (unsigned) argument to enum #1196
 - Correct debug info on parameters without storage.
 - Fix location on foreach debug output.
+- Compiler crash on designated initializer for structs with bitstruct.
 
 ### Stdlib changes
 - Add 'zstr' variants for `string::new_format` / `string::tformat`.
diff --git a/src/compiler/llvm_codegen_expr.c b/src/compiler/llvm_codegen_expr.c
index 85c03dfdb..9946251e2 100644
--- a/src/compiler/llvm_codegen_expr.c
+++ b/src/compiler/llvm_codegen_expr.c
@@ -2004,7 +2004,7 @@ static void llvm_emit_initialize_designated_element(GenContext *c, BEValue *ref,
 		{
 			Decl *decl = ref->type->canonical->decl->strukt.members[curr->index];
 			offset += decl->offset;
-			Type *type = decl->type->canonical;
+			Type *type = type_flatten(decl->type);
 			unsigned decl_alignment = decl->alignment;
 			if (ref->type->type_kind == TYPE_UNION)
 			{
@@ -2017,11 +2017,11 @@ static void llvm_emit_initialize_designated_element(GenContext *c, BEValue *ref,
 			{
 				llvm_value_struct_gep(c, &value, ref, (unsigned) curr->index);
 			}
-			if (decl->decl_kind == DECL_BITSTRUCT)
+			if (type->type_kind == TYPE_BITSTRUCT)
 			{
 				assert(llvm_value_is_addr(&value));
 				assert(last == current + 1);
-				Decl *member = decl->bitstruct.members[last[0]->index];
+				Decl *member = type->decl->bitstruct.members[last[0]->index];
 				// Special handling of bitstructs.
 				Type *underlying_type = value.type;
 				assert(!emitted_value);
diff --git a/test/test_suite/bitstruct/bitstruct_direct_in_struct.c3t b/test/test_suite/bitstruct/bitstruct_direct_in_struct.c3t
new file mode 100644
index 000000000..4d23a5105
--- /dev/null
+++ b/test/test_suite/bitstruct/bitstruct_direct_in_struct.c3t
@@ -0,0 +1,38 @@
+// #target: macos-x64
+module test;
+bitstruct Flags : int {
+  bool flag1;
+}
+
+struct Foo {
+  long x;
+  Flags flags;
+}
+
+fn int main(String[] args) {
+  long x;
+  Foo foo = {
+    .x = x,
+    .flags.flag1 = true,
+  };
+  return 0;
+}
+
+/* #expect: test.ll
+
+  store ptr %0, ptr %args, align 8
+  %ptradd = getelementptr inbounds i8, ptr %args, i64 8
+  store i64 %1, ptr %ptradd, align 8
+  store i64 0, ptr %x, align 8
+  store i64 0, ptr %foo, align 8
+  %ptradd1 = getelementptr inbounds i8, ptr %foo, i64 8
+  store i32 0, ptr %ptradd1, align 8
+  %2 = load i64, ptr %x, align 8
+  store i64 %2, ptr %foo, align 8
+  %ptradd2 = getelementptr inbounds i8, ptr %foo, i64 8
+  %3 = load i32, ptr %ptradd2, align 8
+  %4 = and i32 %3, -2
+  %5 = or i32 %4, 1
+  store i32 %5, ptr %ptradd2, align 8
+  ret i32 0
+