conditionally unwrapping while loops

compiler_tests.odin

@@ -11514,6 +11514,39 @@ braceless_while_compiles_and_runs :: proc(t: ^testing.T) {
 	testing.expect_value(t, state.exit_code, 42)
 }
 
+@(test)
+while_unwrap_compiles_and_runs_at_runtime_and_comptime :: proc(t: ^testing.T) {
+	directory := "/tmp/brolang-test-while-unwrap"
+	main_path := "/tmp/brolang-test-while-unwrap/main.bro"
+	output := "/tmp/brolang-test-while-unwrap-output"
+	text := `next func(index @mut usize, limit usize) ?i32 {
+	if (index^ == limit) return null
+	index^ += 1
+	return i32(index^)
+}
+sum func(limit, cap usize) i32 {
+	index usize := 0
+	total i32 := 0
+	while next(&index, limit) |value : usize(value) <= cap| : total += value {}
+	return total
+}
+COMPTIME_SUM :: $sum(4, 4)
+COMPTIME_GUARDED :: $sum(5, 3)
+main func() i32 {
+	if COMPTIME_SUM != 10 or COMPTIME_GUARDED != 6 { return 1 }
+	return sum(4, 4) + sum(5, 3) - 16
+}
+`
+	_ = os2.remove_all(directory)
+	defer _ = os2.remove_all(directory)
+	defer _ = os.remove(output)
+	testing.expect(t, os.make_directory(directory) == nil)
+	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
+	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
+	state := run_executable(output)
+	testing.expect_value(t, state.exit_code, 0)
+}
+
 @(test)
 parser_diagnoses_braceless_for_and_unwrap_without_parens_or_call :: proc(t: ^testing.T) {
 	text := `main func() void {