Concatenate(String, RefOf) is broken

[d-tatianin]

Steps to reproduce:

1. Compile this code

DefinitionBlock ("", "DSDT", 2, "TTEST", "TESTTABL", 0xF0F0F0F0)
{
    Scope(_SB) {
        Method(_INI, 0, NotSerialized) {
            Local0 = 123
            Debug = Concatenate("Test", RefOf(Local0))
        }
    }
}

2. ./laiexec test.aml

This crashes in lai_exec_string_length:

ACPI namespace created, total of 9 predefined objects.
Executing _SB_._INI
assertion failed: str->type == LAI_STRING at ../subprojects/lai/core/exec-operand.c:14

Sidenote:
Concatenate with any ref type produces weird output like (uninitialized) but at least it doesn't crash