diff --git a/library/alloc/src/task.rs b/library/alloc/src/task.rs
index 9d8e309a978d9..5d9772b878b03 100644
--- a/library/alloc/src/task.rs
+++ b/library/alloc/src/task.rs
@@ -39,6 +39,7 @@ use crate::sync::Arc;
 /// use std::sync::Arc;
 /// use std::task::{Context, Poll, Wake};
 /// use std::thread::{self, Thread};
+/// use core::pin::pin;
 ///
 /// /// A waker that wakes up the current thread when called.
 /// struct ThreadWaker(Thread);
@@ -52,7 +53,7 @@ use crate::sync::Arc;
 /// /// Run a future to completion on the current thread.
 /// fn block_on<T>(fut: impl Future<Output = T>) -> T {
 ///     // Pin the future so it can be polled.
-///     let mut fut = Box::pin(fut);
+///     let mut fut = pin!(fut);
 ///
 ///     // Create a new context to be passed to the future.
 ///     let t = thread::current();
diff --git a/src/bootstrap/configure.py b/src/bootstrap/configure.py
index abd28b4005d0b..5a056d364ca5b 100755
--- a/src/bootstrap/configure.py
+++ b/src/bootstrap/configure.py
@@ -521,6 +521,10 @@ def write_config_toml(writer, section_order, targets, sections):
         else:
             writer = write_uncommented(sections[section], writer)
 
+def quit_if_file_exists(file):
+    if os.path.isfile(file):
+        p("Existing '" + file + "' detected. EXIING")
+        quit()
 
 if __name__ == "__main__":
     p("processing command line")
@@ -528,6 +532,8 @@ def write_config_toml(writer, section_order, targets, sections):
     # TOML we're going to write out
     p("")
     section_order, sections, targets = parse_args(sys.argv[1:])
+    # If 'config.toml' already exists, exit the script at this point
+    quit_if_file_exists('config.toml')
 
     # Now that we've built up our `config.toml`, write it all out in the same
     # order that we read it in.