From 1fd617d6df6055516b5cc4b265037e4188806d1d Mon Sep 17 00:00:00 2001
From: Jeremy Stucki <stucki.jeremy@gmail.com>
Date: Mon, 24 Jun 2019 11:21:29 +0200
Subject: [PATCH] Add test for unnecessary_flat_map

---
 tests/ui/unnecessary_flat_map.rs     |  6 ++++++
 tests/ui/unnecessary_flat_map.stderr | 10 ++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 tests/ui/unnecessary_flat_map.rs
 create mode 100644 tests/ui/unnecessary_flat_map.stderr

diff --git a/tests/ui/unnecessary_flat_map.rs b/tests/ui/unnecessary_flat_map.rs
new file mode 100644
index 000000000000..d0072eca9d22
--- /dev/null
+++ b/tests/ui/unnecessary_flat_map.rs
@@ -0,0 +1,6 @@
+#![warn(clippy::flat_map)]
+
+fn main() {
+    let iterator = [[0, 1], [2, 3], [4, 5]].iter();
+    iterator.flat_map(|x| x);
+}
diff --git a/tests/ui/unnecessary_flat_map.stderr b/tests/ui/unnecessary_flat_map.stderr
new file mode 100644
index 000000000000..9ebef07f1b7e
--- /dev/null
+++ b/tests/ui/unnecessary_flat_map.stderr
@@ -0,0 +1,10 @@
+error: called `flat_map(|x| x)` on an `Iterator`. This can be simplified by calling `flatten().`
+  --> $DIR/unnecessary_flat_map.rs:5:5
+   |
+LL |     iterator.flat_map(|x| x);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::flat-map` implied by `-D warnings`
+
+error: aborting due to previous error
+