Function typed_fetch_refusal 

pub fn typed_fetch_refusal(ty: &TypeExpr<'_>, interner: &Interner) -> String

What every tier says of Get … as <ty> when the derived JSON codec cannot read ty: a typed request decodes its answer through fromJson_<T> for a declared record, fromJsonSeq_<T> for a list of records or scalars, and takes Text verbatim — nothing else.