1 files changed, 123 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/len_without_is_empty.stderr b/src/tools/clippy/tests/ui/len_without_is_empty.stderr
new file mode 100644
index 000000000..a1f48f761
--- /dev/null
+++ b/src/tools/clippy/tests/ui/len_without_is_empty.stderr
@@ -0,0 +1,123 @@
+error: struct `PubOne` has a public `len` method, but no `is_empty` method
+  --> $DIR/len_without_is_empty.rs:7:5
+   |
+LL |     pub fn len(&self) -> isize {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::len-without-is-empty` implied by `-D warnings`
+
+error: trait `PubTraitsToo` has a `len` method but no (possibly inherited) `is_empty` method
+  --> $DIR/len_without_is_empty.rs:55:1
+   |
+LL | / pub trait PubTraitsToo {
+LL | |     fn len(&self) -> isize;
+LL | | }
+   | |_^
+
+error: struct `HasIsEmpty` has a public `len` method, but a private `is_empty` method
+  --> $DIR/len_without_is_empty.rs:68:5
+   |
+LL |     pub fn len(&self) -> isize {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: `is_empty` defined here
+  --> $DIR/len_without_is_empty.rs:72:5
+   |
+LL |     fn is_empty(&self) -> bool {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: struct `HasWrongIsEmpty` has a public `len` method, but the `is_empty` method has an unexpected signature
+  --> $DIR/len_without_is_empty.rs:80:5
+   |
+LL |     pub fn len(&self) -> isize {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: `is_empty` defined here
+  --> $DIR/len_without_is_empty.rs:84:5
+   |
+LL |     pub fn is_empty(&self, x: u32) -> bool {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: expected signature: `(&self) -> bool`
+
+error: struct `MismatchedSelf` has a public `len` method, but the `is_empty` method has an unexpected signature
+  --> $DIR/len_without_is_empty.rs:92:5
+   |
+LL |     pub fn len(self) -> isize {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: `is_empty` defined here
+  --> $DIR/len_without_is_empty.rs:96:5
+   |
+LL |     pub fn is_empty(&self) -> bool {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: expected signature: `(self) -> bool`
+
+error: trait `DependsOnFoo` has a `len` method but no (possibly inherited) `is_empty` method
+  --> $DIR/len_without_is_empty.rs:171:1
+   |
+LL | / pub trait DependsOnFoo: Foo {
+LL | |     fn len(&mut self) -> usize;
+LL | | }
+   | |_^
+
+error: struct `OptionalLen3` has a public `len` method, but the `is_empty` method has an unexpected signature
+  --> $DIR/len_without_is_empty.rs:216:5
+   |
+LL |     pub fn len(&self) -> usize {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: `is_empty` defined here
+  --> $DIR/len_without_is_empty.rs:221:5
+   |
+LL |     pub fn is_empty(&self) -> Option<bool> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: expected signature: `(&self) -> bool`
+
+error: struct `ResultLen` has a public `len` method, but the `is_empty` method has an unexpected signature
+  --> $DIR/len_without_is_empty.rs:228:5
+   |
+LL |     pub fn len(&self) -> Result<usize, ()> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: `is_empty` defined here
+  --> $DIR/len_without_is_empty.rs:233:5
+   |
+LL |     pub fn is_empty(&self) -> Option<bool> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: expected signature: `(&self) -> bool` or `(&self) -> Result<bool>
+
+error: this returns a `Result<_, ()>`
+  --> $DIR/len_without_is_empty.rs:228:5
+   |
+LL |     pub fn len(&self) -> Result<usize, ()> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::result-unit-err` implied by `-D warnings`
+   = help: use a custom `Error` type instead
+
+error: this returns a `Result<_, ()>`
+  --> $DIR/len_without_is_empty.rs:240:5
+   |
+LL |     pub fn len(&self) -> Result<usize, ()> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a custom `Error` type instead
+
+error: this returns a `Result<_, ()>`
+  --> $DIR/len_without_is_empty.rs:244:5
+   |
+LL |     pub fn is_empty(&self) -> Result<bool, ()> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a custom `Error` type instead
+
+error: this returns a `Result<_, ()>`
+  --> $DIR/len_without_is_empty.rs:251:5
+   |
+LL |     pub fn len(&self) -> Result<usize, ()> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a custom `Error` type instead
+
+error: aborting due to 12 previous errors
+