Merge pull request #2836 from jakubtomsu/fix-zero-length-enum-array

Allow zero-length enum array (to stay consistent with `[0]T`)

src/check_type.cpp

@@ -2797,7 +2797,7 @@ gb_internal bool check_type_internal(CheckerContext *ctx, Ast *e, Type **type, T
 				Type *bt = base_type(index);
 				GB_ASSERT(bt->kind == Type_Enum);
 
-				Type *t = alloc_type_enumerated_array(elem, index, bt->Enum.min_value, bt->Enum.max_value, Token_Invalid);
+				Type *t = alloc_type_enumerated_array(elem, index, bt->Enum.min_value, bt->Enum.max_value, bt->Enum.fields.count, Token_Invalid);
 
 				bool is_sparse = false;
 				if (at->tag != nullptr) {

src/types.cpp

@@ -983,7 +983,7 @@ gb_internal Type *alloc_type_matrix(Type *elem, i64 row_count, i64 column_count,
 }
 
 
-gb_internal Type *alloc_type_enumerated_array(Type *elem, Type *index, ExactValue const *min_value, ExactValue const *max_value, TokenKind op) {
+gb_internal Type *alloc_type_enumerated_array(Type *elem, Type *index, ExactValue const *min_value, ExactValue const *max_value, isize count, TokenKind op) {
 	Type *t = alloc_type(Type_EnumeratedArray);
 	t->EnumeratedArray.elem = elem;
 	t->EnumeratedArray.index = index;
@@ -993,7 +993,11 @@ gb_internal Type *alloc_type_enumerated_array(Type *elem, Type *index, ExactValu
 	gb_memmove(t->EnumeratedArray.max_value, max_value, gb_size_of(ExactValue));
 	t->EnumeratedArray.op = op;
 
-	t->EnumeratedArray.count = 1 + exact_value_to_i64(exact_value_sub(*max_value, *min_value));
+	if (count == 0) {
+		t->EnumeratedArray.count = 0;
+	} else {
+		t->EnumeratedArray.count = 1 + exact_value_to_i64(exact_value_sub(*max_value, *min_value));
+	}
 	return t;
 }