New upstream version 1.52.1+dfsg1

[rustc.git] / src / tools / clippy / tests / ui / mut_from_ref.rs

diff --git a/src/tools/clippy/tests/ui/mut_from_ref.rs b/src/tools/clippy/tests/ui/mut_from_ref.rs
new file mode 100644 (file)
index 0000000..a9a04c8
--- /dev/null
+++ b/src/tools/clippy/tests/ui/mut_from_ref.rs
@@ -0,0 +1,46 @@
+#![allow(unused)]
+#![warn(clippy::mut_from_ref)]
+
+struct Foo;
+
+impl Foo {
+    fn this_wont_hurt_a_bit(&self) -> &mut Foo {
+        unimplemented!()
+    }
+}
+
+trait Ouch {
+    fn ouch(x: &Foo) -> &mut Foo;
+}
+
+impl Ouch for Foo {
+    fn ouch(x: &Foo) -> &mut Foo {
+        unimplemented!()
+    }
+}
+
+fn fail(x: &u32) -> &mut u16 {
+    unimplemented!()
+}
+
+fn fail_lifetime<'a>(x: &'a u32, y: &mut u32) -> &'a mut u32 {
+    unimplemented!()
+}
+
+fn fail_double<'a, 'b>(x: &'a u32, y: &'a u32, z: &'b mut u32) -> &'a mut u32 {
+    unimplemented!()
+}
+
+// this is OK, because the result borrows y
+fn works<'a>(x: &u32, y: &'a mut u32) -> &'a mut u32 {
+    unimplemented!()
+}
+
+// this is also OK, because the result could borrow y
+fn also_works<'a>(x: &'a u32, y: &'a mut u32) -> &'a mut u32 {
+    unimplemented!()
+}
+
+fn main() {
+    //TODO
+}