```private fun FirSession.nullaryAnnotationFromId(...

# compiler

[min]

private fun FirSession.nullaryAnnotationFromId(id: ClassId): FirAnnotation? {
    val annotationTypeRef = this.classFromId(id)
        ?.defaultType() // Or should I use `constructType` here?
        ?.toFirResolvedTypeRef() ?: return null
    return buildAnnotationCall(fun (callBuilder) {
        callBuilder.annotationTypeRef = annotationTypeRef
    })
}

What’s the difference between defaultType and constructType?

[Youssef Shoaib [MOD]]

If you don't have type parameters, I think they're the same
IIRC, `defaultType`is the type inside the class, I.e. if you have class Foo<T> the default type is Foo<T> (yes including the type parameter). constructType actually creates a type and lets you pass in type arguments, so it's almost surely what you want here.
Purely operating from memory though. I'd Go To Definition on each and see the implementation

[min]

@Youssef Shoaib [MOD] Thanks! Are you also familiar with the difference between FirReceiverParameterSymbol#resolvedType and FirReceiverParameterSymbol#fir#typeRef?