universal charstring is unconditionally incompatible with charstring
Summary
According to 6.3.1 in the standard, a universal charstring can be assigned as value to a charstring iff the former does not include special characters.
Steps and/or TTCN-3 code to reproduce
testcase types_assignments() runs on ct_empty{
v_uc := "a";
v_myCharString := v_uc;
setverdict(pass);
v_uc := "áéíőű";
@try{
v_myCharString := v_uc;
}
@catch(msg){
log(msg);
setverdict(pass);
}
}
What is the current bug behavior?
This does not compile.
What is the expected correct behavior?
Test case passes.
Relevant logs and/or screenshots
```../src/assignments.ttcn:527.23-26: error: Type mismatch: a value of type charstring' was expected instead of
universal charstring'
## Possible fixes
## Titan version
8.1.0
## Platform details (OS type and version)
Microsoft Windows 10 Enterprise 10.0.19042
/cc @aknappqwt @mmagyari