@@ -274,19 +274,9 @@ impl Client {
274274where
275275T : ?Sized +ToStatement ,
276276{
277- let stream =self . query_raw ( statement, slice_iter ( params) ) . await ?;
278- pin_mut ! ( stream) ;
279-
280- let row =match stream. try_next ( ) . await ?{
281- Some ( row) => row,
282- None =>return Err ( Error :: row_count ( ) ) ,
283- } ;
284-
285- if stream. try_next ( ) . await ?. is_some ( ) {
286- return Err ( Error :: row_count ( ) ) ;
287- }
288-
289- Ok ( row)
277+ self . query_opt ( statement, params)
278+ . await
279+ . and_then ( |res| res. ok_or_else ( Error :: row_count) )
290280}
291281
292282/// Executes a statements which returns zero or one rows, returning it.
@@ -310,16 +300,22 @@ impl Client {
310300let stream =self . query_raw ( statement, slice_iter ( params) ) . await ?;
311301pin_mut ! ( stream) ;
312302
313- let row =match stream. try_next ( ) . await ?{
314- Some ( row) => row,
315- None =>return Ok ( None ) ,
316- } ;
303+ let mut first =None ;
304+
305+ // Originally this was two calls to `try_next().await?`,
306+ // once for the first element, and second to error if more than one.
307+ //
308+ // However, this new form with only one .await in a loop generates
309+ // slightly smaller codegen/stack usage for the resulting future.
310+ while let Some ( row) = stream. try_next ( ) . await ?{
311+ if first. is_some ( ) {
312+ return Err ( Error :: row_count ( ) ) ;
313+ }
317314
318- if stream. try_next ( ) . await ?. is_some ( ) {
319- return Err ( Error :: row_count ( ) ) ;
315+ first =Some ( row) ;
320316}
321317
322- Ok ( Some ( row ) )
318+ Ok ( first )
323319}
324320
325321/// The maximally flexible version of [`query`].