diff --git a/src/schema_compile.c b/src/schema_compile.c
index 68c0d68..d93f374 100644
--- a/src/schema_compile.c
+++ b/src/schema_compile.c
@@ -862,6 +862,11 @@
 
     assert(node->nodetype & (LYS_LEAF | LYS_LEAFLIST));
 
+    if (lref->realtype) {
+        /* already resolved, may happen (shared union typedef with a leafref) */
+        return LY_SUCCESS;
+    }
+
     /* first implement all the modules in the path */
     LY_CHECK_RET(lys_compile_expr_implement(ctx->ctx, lref->path, LY_VALUE_SCHEMA_RESOLVED, lref->prefixes, 1, unres, NULL));
 
diff --git a/tests/utests/schema/test_tree_schema_compile.c b/tests/utests/schema/test_tree_schema_compile.c
index 265a3fa..e9826cd 100644
--- a/tests/utests/schema/test_tree_schema_compile.c
+++ b/tests/utests/schema/test_tree_schema_compile.c
@@ -1,9 +1,10 @@
-/*
+/**
  * @file test_tree_schema_compile.c
- * @author: Radek Krejci <rkrejci@cesnet.cz>
+ * @author Radek Krejci <rkrejci@cesnet.cz>
+ * @author Michal Vasko <mvasko@cesnet.cz>
  * @brief unit tests for functions from parser_yang.c
  *
- * Copyright (c) 2018 CESNET, z.s.p.o.
+ * Copyright (c) 2018 - 2023 CESNET, z.s.p.o.
  *
  * This source code is licensed under BSD 3-Clause License (the "License").
  * You may not use this file except in compliance with the License.
@@ -1923,6 +1924,13 @@
     assert_int_equal(LY_TYPE_BOOL, ((struct lysc_node_leaf *)mod->compiled->data)->dflt->realtype->basetype);
     assert_int_equal(1, ((struct lysc_node_leaf *)mod->compiled->data)->dflt->boolean);
 
+    /* union reference */
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, "module m {namespace urn:m;prefix m;"
+            "typedef s-ref {type union {type leafref {path '/str';}}}"
+            "leaf str {type string {length \"1..16\" {error-message \"Custom message\";}}}"
+            "leaf ref1 {type s-ref;}"
+            "leaf ref2 {type s-ref;}}", LYS_IN_YANG, NULL));
+
     /* invalid paths */
     assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, "module aa {namespace urn:aa;prefix aa;container a {leaf target2 {type uint8;}}"
             "leaf ref1 {type leafref {path ../a/invalid;}}}", LYS_IN_YANG, &mod));