Rollup merge of #41435 - estebank:issue-33884, r=nikomatsakis

Add test for issue 33884

Fix #33884.

r=nikomatsakis

Author: frewsxcv

src/test/ui/span/issue-33884.rs

@@ -0,0 +1,27 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::net::TcpListener;
+use std::net::TcpStream;
+use std::io::{self, Read, Write};
+
+fn handle_client(stream: TcpStream) -> io::Result<()> {
+    stream.write_fmt(format!("message received"))
+}
+
+fn main() {
+    if let Ok(listener) = TcpListener::bind("127.0.0.1:8080") {
+        for incoming in listener.incoming() {
+            if let Ok(stream) = incoming {
+                handle_client(stream);
+            }
+        }
+    }
+}

src/test/ui/span/issue-33884.stderr

@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-33884.rs:16:22
+   |
+16 |     stream.write_fmt(format!("message received"))
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected struct `std::fmt::Arguments`, found struct `std::string::String`
+   |
+   = note: expected type `std::fmt::Arguments<'_>`
+              found type `std::string::String`
+   = note: this error originates in a macro outside of the current crate
+
+error: aborting due to previous error
+