Method build_let

src/expr-test-util/src/lib.rs:497–526

(&mut self, stream_iter: &mut I)

    }

    fn build_let<I>(&mut self, stream_iter: &mut I) -> Result<MirRelationExpr, String>
    where
        I: Iterator<Item = TokenTree>,
    {
        let name = match stream_iter.next() {
            Some(TokenTree::Ident(ident)) => Ok(ident.to_string()),
            invalid_token => Err(format!(
                "Invalid let specification {:?}",
                invalid_token.map(|token_tree| format!("`{}`", token_tree))
            )),
        }?;

        let value: MirRelationExpr = deserialize(stream_iter, "MirRelationExpr", self)?;

        let (id, prev) = self.scope.insert(&name, value.typ());

        let body: MirRelationExpr = deserialize(stream_iter, "MirRelationExpr", self)?;

        if let Some((old_id, old_val)) = prev {
            self.scope.set(&name, old_id, old_val);
        } else {
            self.scope.remove(&name)
        }

        Ok(MirRelationExpr::Let {
            id,
            value: Box::new(value),
            body: Box::new(body),
        })
    }

    fn build_union<I>(&mut self, stream_iter: &mut I) -> Result<MirRelationExpr, String>
    where