diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index afa6ffdf6..f23d79bd5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -184,7 +184,7 @@ jobs:
       fail-fast: false
       matrix:
         build_type: [Release, Debug]
-        llvm_version: [15, 16]
+        llvm_version: [16]
 
     steps:
       - uses: actions/checkout@v3
diff --git a/lib/std/core/allocators/dynamic_arena.c3 b/lib/std/core/allocators/dynamic_arena.c3
index 8804d18cd..e880ada38 100644
--- a/lib/std/core/allocators/dynamic_arena.c3
+++ b/lib/std/core/allocators/dynamic_arena.c3
@@ -17,19 +17,19 @@ struct DynamicArenaAllocator
  * @require page_size >= 128
  * @require this != null
  **/
-fn void DynamicArenaAllocator.init(DynamicArenaAllocator* this, usz page_size, Allocator* backing_allocator = mem::heap())
+fn void DynamicArenaAllocator.init(DynamicArenaAllocator* this, usz page_size, Allocator* using = mem::heap())
 {
 	this.function = &dynamic_arena_allocator_function;
 	this.page = null;
 	this.unused_page = null;
 	this.page_size = page_size;
-	this.backing_allocator = backing_allocator;
+	this.backing_allocator = using;
 }
 
 /**
  * @require this != null
  **/
-fn void DynamicArenaAllocator.destroy(DynamicArenaAllocator* this)
+fn void DynamicArenaAllocator.free(DynamicArenaAllocator* this)
 {
 	DynamicArenaPage* page = this.page;
 	while (page)
@@ -67,7 +67,7 @@ struct DynamicArenaChunk @local
  * @require ptr && this
  * @require this.page `tried to free pointer on invalid allocator`
  */
-fn void DynamicArenaAllocator.free(DynamicArenaAllocator* this, void* ptr) @private
+fn void DynamicArenaAllocator.free_ptr(DynamicArenaAllocator* this, void* ptr) @private
 {
 	DynamicArenaPage* current_page = this.page;
 	if (ptr == current_page.last_ptr)
@@ -226,7 +226,7 @@ fn void*! dynamic_arena_allocator_function(Allocator* data, usz size, usz alignm
 			if (!size)
 			{
 				if (!old_pointer) return null;
-				allocator.free(old_pointer);
+				allocator.free_ptr(old_pointer);
 				return null;
 			}
 			if (!old_pointer) return allocator._alloc(size, alignment, offset);
@@ -235,7 +235,7 @@ fn void*! dynamic_arena_allocator_function(Allocator* data, usz size, usz alignm
 		case ALIGNED_FREE:
 		case FREE:
 			if (!old_pointer) return null;
-			allocator.free(old_pointer);
+			allocator.free_ptr(old_pointer);
 			return null;
 		case MARK:
 			unreachable("Tried to mark a dynamic arena");
diff --git a/lib/std/core/allocators/temp_allocator.c3 b/lib/std/core/allocators/temp_allocator.c3
index 4a0a26af8..58a5b4ff4 100644
--- a/lib/std/core/allocators/temp_allocator.c3
+++ b/lib/std/core/allocators/temp_allocator.c3
@@ -37,12 +37,12 @@ macro bool TempAllocatorPage.is_aligned(TempAllocatorPage* page) => page.size &
 /**
  * @require size >= 16
  **/
-fn TempAllocator*! new_temp(usz size, Allocator* backing_allocator)
+fn TempAllocator*! new_temp(usz size, Allocator* using)
 {
-	TempAllocator* allocator = malloc_checked(TempAllocator, .using = backing_allocator, .end_padding = size)!;
+	TempAllocator* allocator = malloc_checked(TempAllocator, .using = using, .end_padding = size)!;
 	allocator.last_page = null;
 	allocator.function = &temp_allocator_function;
-	allocator.backing_allocator = backing_allocator;
+	allocator.backing_allocator = using;
 	allocator.used = 0;
 	allocator.capacity = size;
 	return allocator;
diff --git a/lib/std/core/allocators/tracking_allocator.c3 b/lib/std/core/allocators/tracking_allocator.c3
index 22176955b..8efc5beab 100644
--- a/lib/std/core/allocators/tracking_allocator.c3
+++ b/lib/std/core/allocators/tracking_allocator.c3
@@ -24,10 +24,10 @@ struct TrackingAllocator
  *
  * @require this != null
  **/
-fn void TrackingAllocator.init(TrackingAllocator* this, Allocator* allocator)
+fn void TrackingAllocator.init(TrackingAllocator* this, Allocator* using)
 {
-	*this = { .inner_allocator = allocator, .allocator.function = &tracking_allocator_fn };
-	this.map.init(.using = allocator);
+	*this = { .inner_allocator = using, .allocator.function = &tracking_allocator_fn };
+	this.map.init(.using = using);
 }
 
 fn void TrackingAllocator.free(TrackingAllocator* this)
diff --git a/lib/std/io/io_file.c3 b/lib/std/io/io_file.c3
index 22bb9545e..2298c1930 100644
--- a/lib/std/io/io_file.c3
+++ b/lib/std/io/io_file.c3
@@ -109,7 +109,7 @@ fn usz! File.write(File file, char[] buffer)
  * @param [&in] file
  * @require file.file `File must be initialized`
  */
-fn usz! File.printn(File file, String string)
+fn usz! File.printn(File file, String string = "")
 {
 	usz len = file.print(string)!;
 	if (!libc::putc('\n', file.file)) return IoError.UNKNOWN_ERROR?;
diff --git a/src/compiler/compiler_internal.h b/src/compiler/compiler_internal.h
index f435bfadc..67244b377 100644
--- a/src/compiler/compiler_internal.h
+++ b/src/compiler/compiler_internal.h
@@ -329,7 +329,7 @@ struct Type_
 	void *backend_debug_type;
 	union
 	{
-		// Error, Struct, Union, Typedef, Member
+		// Error, Struct, Union, Typedef, Member, Bitstruct
 		Decl *decl;
 		// int, float, bool
 		TypeBuiltin builtin;
@@ -341,8 +341,6 @@ struct Type_
 		Type *pointer;
 		// Optional
 		Type *optional;
-		// Bitstruct
-		Type *bitstruct;
 	};
 };
 
diff --git a/src/compiler/sema_casts.c b/src/compiler/sema_casts.c
index 4903282a8..6fd4adb48 100644
--- a/src/compiler/sema_casts.c
+++ b/src/compiler/sema_casts.c
@@ -1162,6 +1162,9 @@ static bool cast_from_array(SemaContext *context, Expr *expr, Type *from, Type *
 			// Len must be checked.
 			if (to->array.len != from->array.len) return sema_error_cannot_convert(expr, to_type, false, silent);
 			break;
+		case TYPE_BITSTRUCT:
+			if (to->decl->bitstruct.base_type->type->canonical == from) return cast_with_optional(expr, to_type, add_optional);
+			FALLTHROUGH;
 		default:
 			// No other conversions are allowed.
 			return sema_error_cannot_convert(expr, to_type, false, silent);
@@ -1891,6 +1894,11 @@ static bool cast_inner(Expr *expr, Type *from_type, Type *to, Type *to_type)
 			return false;
 		case TYPE_ARRAY:
 			if (to->type_kind == TYPE_VECTOR) return array_to_vector(expr, to_type);
+			if (to->type_kind == TYPE_BITSTRUCT)
+			{
+				expr->type = to_type;
+				return true;
+			}
 			FALLTHROUGH;
 		case TYPE_STRUCT:
 		case TYPE_UNION:
diff --git a/src/version.h b/src/version.h
index 0a403ab1b..038f60e30 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1 +1 @@
-#define COMPILER_VERSION "0.4.507"
\ No newline at end of file
+#define COMPILER_VERSION "0.4.508"
\ No newline at end of file