Add regression test for #71546

src/test/ui/borrowck/issue-71546.rs

@@ -0,0 +1,16 @@
+// Regression test for #71546.
+
+pub fn serialize_as_csv<V>(value: &V) -> Result<String, &str>
+where
+ V: 'static,
+ for<'a> &'a V: IntoIterator,
+ for<'a> <&'a V as IntoIterator>::Item: ToString + 'static,
+{
+ let csv_str: String = value //~ ERROR: the associated type `<&'a V as IntoIterator>::Item` may not live long enough
+ .into_iter()
+ .map(|elem| elem.to_string())
+ .collect::<String>();
+ Ok(csv_str)
+}
+
+fn main() {}

src/test/ui/borrowck/issue-71546.stderr

@@ -0,0 +1,20 @@
+error[E0310]: the associated type `<&'a V as IntoIterator>::Item` may not live long enough
+ --> $DIR/issue-71546.rs:9:27
+ |
+LL | let csv_str: String = value
+ | ___________________________^
+LL | | .into_iter()
+LL | | .map(|elem| elem.to_string())
+ | |_____________________________________^
+ |
+ = help: consider adding an explicit lifetime bound `<&'a V as IntoIterator>::Item: 'static`...
+ = note: ...so that the type `<&'a V as IntoIterator>::Item` will meet its required lifetime bounds...
+note: ...that is required by this bound
+ --> $DIR/issue-71546.rs:7:55
+ |
+LL | for<'a> <&'a V as IntoIterator>::Item: ToString + 'static,
+ | ^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0310`.