add mcve for issue 72442

Author: csmoe

src/test/ui/async-await/issue-72442.rs

@@ -0,0 +1,25 @@
+// edition:2018
+
+use std::fs::File;
+use std::future::Future;
+use std::io::prelude::*;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    block_on(async {
+        {
+            let path = std::path::Path::new(".");
+            let mut f = File::open(path.to_str())?;
+            //~^ ERROR the trait bound `std::option::Option<&str>: std::convert::AsRef<std::path::Path>` is not satisfied
+            let mut src = String::new();
+            f.read_to_string(&mut src)?;
+            Ok(())
+        }
+    })
+}
+
+fn block_on<F>(f: F) -> F::Output
+where
+    F: Future<Output = Result<(), Box<dyn std::error::Error>>>,
+{
+    Ok(())
+}