Method next

datafusion/common/src/error.rs:617–634

(&mut self)

            type Item = &'a Diagnostic;

            fn next(&mut self) -> Option<Self::Item> {
                loop {
                    if let DataFusionError::Diagnostic(diagnostics, source) = self.head {
                        self.head = source.as_ref();
                        return Some(diagnostics);
                    }

                    if let Some(source) = self
                        .head
                        .source()
                        .and_then(|source| source.downcast_ref::<DataFusionError>())
                    {
                        self.head = source;
                    } else {
                        return None;
                    }
                }
            }
        }

        DiagnosticsIterator { head: self }.next()