diff --git a/lib/desugar.c b/lib/desugar.c
index 2db4812..454c759 100644
--- a/lib/desugar.c
+++ b/lib/desugar.c
@@ -117,8 +117,11 @@ static void desugar_term(regex_term_t *term)
 		desugar_class(term);
 		break;
 
-	case REGEX_TERM_LITERAL:
 	case REGEX_TERM_SUBEXPR:
+		desugar_regex(&term->subexpr);
+		break;
+
+	case REGEX_TERM_LITERAL:
 	case REGEX_TERM_EMPTY:
 		break;
 	}
diff --git a/tests/desugar_tests.c b/tests/desugar_tests.c
index 92a9e1d..a3226d2 100644
--- a/tests/desugar_tests.c
+++ b/tests/desugar_tests.c
@@ -287,6 +287,60 @@ static void class_abc_becomes_subexpr_a_or_b_or_c(void)
 	regex_free(&t);
 }
 
+static void subexpr_a_qmark_becomes_subexpr_subexpr_empty_or_a(void)
+{
+	regex_term_t *inner_terms = malloc(1 * sizeof(regex_term_t));
+	inner_terms[0].quantifier = REGEX_QUANTIFIER_QMARK;
+	inner_terms[0].type = REGEX_TERM_LITERAL;
+	inner_terms[0].literal = 'a';
+	regex_sequence_t *inner_alternatives
+	    = malloc(1 * sizeof(regex_sequence_t));
+	inner_alternatives[0].count = inner_alternatives[0].capacity = 1;
+	inner_alternatives[0].contents = inner_terms;
+	regex_term_t *terms = malloc(1 * sizeof(regex_term_t));
+	terms[0].quantifier = REGEX_QUANTIFIER_NONE;
+	terms[0].type = REGEX_TERM_SUBEXPR;
+	terms[0].subexpr.count = terms[0].subexpr.capacity = 1;
+	terms[0].subexpr.contents = inner_alternatives;
+	regex_sequence_t *alternatives = malloc(1 * sizeof(regex_sequence_t));
+	alternatives[0].count = alternatives[0].capacity = 1;
+	alternatives[0].contents = terms;
+	regex_t t = { .count = 1, .capacity = 1, .contents = alternatives };
+
+	desugar_regex(&t);
+
+	ASSERT_EQ(1, t.count);
+	ASSERT_EQ(1, t.contents[0].count);
+	ASSERT_EQ(REGEX_QUANTIFIER_NONE, t.contents[0].contents[0].quantifier);
+	ASSERT_EQ(REGEX_TERM_SUBEXPR, t.contents[0].contents[0].type);
+
+	const regex_t *inner;
+
+	inner = &t.contents[0].contents[0].subexpr;
+	ASSERT_EQ(1, inner->count);
+	ASSERT_EQ(1, inner->contents[0].count);
+	ASSERT_EQ(
+	    REGEX_QUANTIFIER_NONE, inner->contents[0].contents[0].quantifier);
+	ASSERT_EQ(REGEX_TERM_SUBEXPR, inner->contents[0].contents[0].type);
+
+	inner = &inner->contents[0].contents[0].subexpr;
+	ASSERT_EQ(2, inner->count);
+	ASSERT_NOT_NULL(inner->contents);
+	ASSERT_EQ(1, inner->contents[0].count);
+	ASSERT_NOT_NULL(inner->contents[0].contents);
+	ASSERT_EQ(
+	    REGEX_QUANTIFIER_NONE, inner->contents[0].contents[0].quantifier);
+	ASSERT_EQ(REGEX_TERM_EMPTY, inner->contents[0].contents[0].type);
+	ASSERT_EQ(1, inner->contents[1].count);
+	ASSERT_NOT_NULL(inner->contents[1].contents);
+	ASSERT_EQ(
+	    REGEX_QUANTIFIER_NONE, inner->contents[1].contents[0].quantifier);
+	ASSERT_EQ(REGEX_TERM_LITERAL, inner->contents[1].contents[0].type);
+	ASSERT_EQ('a', inner->contents[1].contents[0].literal);
+
+	regex_free(&t);
+}
+
 int main(void)
 {
 	TESTING_BEGIN();
@@ -298,5 +352,6 @@ int main(void)
 	a_plus_becomes_subexpr_aa_star();
 	a_qmark_becomes_subexpr_empty_or_a();
 	class_abc_becomes_subexpr_a_or_b_or_c();
+	subexpr_a_qmark_becomes_subexpr_subexpr_empty_or_a();
 	return TESTING_END();
 }