Fix FlattenCompat::{next, next_back}

timvermeulen · timvermeulen · commit cff1182bcdf0 · 2020-03-17T00:03:43.000+01:00
diff --git a/src/libcore/iter/adapters/flatten.rs b/src/libcore/iter/adapters/flatten.rs
@@ -264,8 +264,9 @@ where
     fn next(&mut self) -> Option<U::Item> {
         loop {
             if let Some(ref mut inner) = self.frontiter {
-                if let elt @ Some(_) = inner.next() {
-                    return elt;
+                match inner.next() {
+                    None => self.frontiter = None,
+                    elt @ Some(_) => return elt,
                 }
             }
             match self.iter.next() {
@@ -351,8 +352,9 @@ where
     fn next_back(&mut self) -> Option<U::Item> {
         loop {
             if let Some(ref mut inner) = self.backiter {
-                if let elt @ Some(_) = inner.next_back() {
-                    return elt;
+                match inner.next_back() {
+                    None => self.backiter = None,
+                    elt @ Some(_) => return elt,
                 }
             }
             match self.iter.next_back() {

Original file line number	Diff line number	Diff line change
`@@ -264,8 +264,9 @@ where`
`264`	`264`	`fn next(&mut self) -> Option<U::Item> {`
`265`	`265`	`loop {`
`266`	`266`	`if let Some(ref mut inner) = self.frontiter {`
`267`		`- if let elt @ Some(_) = inner.next() {`
`268`		`- return elt;`
	`267`	`+ match inner.next() {`
	`268`	`+ None => self.frontiter = None,`
	`269`	`+ elt @ Some(_) => return elt,`
`269`	`270`	`}`
`270`	`271`	`}`
`271`	`272`	`match self.iter.next() {`
`@@ -351,8 +352,9 @@ where`
`351`	`352`	`fn next_back(&mut self) -> Option<U::Item> {`
`352`	`353`	`loop {`
`353`	`354`	`if let Some(ref mut inner) = self.backiter {`
`354`		`- if let elt @ Some(_) = inner.next_back() {`
`355`		`- return elt;`
	`355`	`+ match inner.next_back() {`
	`356`	`+ None => self.backiter = None,`
	`357`	`+ elt @ Some(_) => return elt,`
`356`	`358`	`}`
`357`	`359`	`}`
`358`	`360`	`match self.iter.next_back() {`