diff --git a/libasn1fix/asn1fix_tags.c b/libasn1fix/asn1fix_tags.c
new file mode 100644
index 0000000..ed8c19f
--- /dev/null
+++ b/libasn1fix/asn1fix_tags.c
@@ -0,0 +1,47 @@
+#include "asn1fix_internal.h"
+
+int
+asn1f_fetch_tag(asn1p_t *asn, asn1p_module_t *mod, asn1p_expr_t *expr, struct asn1p_type_tag_s *tag) {
+	int ret;
+
+	if(expr->tag.tag_class != TC_NOCLASS) {
+		*tag = expr->tag;
+		return 0;
+	}
+
+	if(expr->expr_type == A1TC_EXTENSIBLE) {
+		memset(tag, 0, sizeof(*tag));
+		tag->tag_class = -1;
+		return 0;
+	}
+
+	if(expr->meta_type == AMT_TYPE) {
+		memset(tag, 0, sizeof(*tag));
+		tag->tag_class = TC_UNIVERSAL;
+		tag->tag_value = expr_type2uclass_value[expr->expr_type];
+		return (tag->tag_value == 0) ? -1 : 0;
+	}
+
+	if(expr->meta_type == AMT_TYPEREF) {
+		arg_t arg;
+
+		memset(&arg, 0, sizeof(arg));
+		arg.asn = asn;
+		arg.mod = mod;
+		arg.expr = expr;
+
+		expr = asn1f_lookup_symbol(&arg, expr->reference, &mod);
+		if(expr == NULL) return -1;
+
+		if(expr->_mark & TM_RECURSION)
+			return -1;
+
+		expr->_mark |= TM_RECURSION;
+		ret = asn1f_fetch_tag(asn, mod, expr, tag);
+		expr->_mark &= ~TM_RECURSION;
+		return ret;
+	}
+
+	return -1;
+}
+