Add more tests

Author: spastorino

tests/ui/ergonomic-clones/closure/expect-region.rs

@@ -0,0 +1,25 @@
+#![feature(ergonomic_clones)]
+#![allow(warnings)]
+
+fn closure_expecting_bound<F>(_: F)
+where
+    F: FnOnce(&u32),
+{
+}
+
+fn expect_bound_supply_named<'x>() {
+    let mut f: Option<&u32> = None;
+
+    // Here we give a type annotation that `x` should be free. We get
+    // an error because of that.
+    closure_expecting_bound(use |x: &'x u32| {
+        //~^ ERROR lifetime may not live long enough
+        //~| ERROR lifetime may not live long enough
+
+        // Borrowck doesn't get a chance to run, but if it did it should error
+        // here.
+        f = Some(x);
+    });
+}
+
+fn main() {}

tests/ui/ergonomic-clones/closure/expect-region.stderr

@@ -0,0 +1,22 @@
+error: lifetime may not live long enough
+  --> $DIR/expect-region.rs:15:34
+   |
+LL | fn expect_bound_supply_named<'x>() {
+   |                              -- lifetime `'x` defined here
+...
+LL |     closure_expecting_bound(use |x: &'x u32| {
+   |                                  ^  - let's call the lifetime of this reference `'1`
+   |                                  |
+   |                                  requires that `'1` must outlive `'x`
+
+error: lifetime may not live long enough
+  --> $DIR/expect-region.rs:15:34
+   |
+LL | fn expect_bound_supply_named<'x>() {
+   |                              -- lifetime `'x` defined here
+...
+LL |     closure_expecting_bound(use |x: &'x u32| {
+   |                                  ^ requires that `'x` must outlive `'static`
+
+error: aborting due to 2 previous errors
+

tests/ui/ergonomic-clones/closure/immutable-outer-variable.fixed

@@ -0,0 +1,15 @@
+//@ run-rustfix
+
+// Point at the captured immutable outer variable
+
+#![feature(ergonomic_clones)]
+
+fn foo(mut f: Box<dyn FnMut()>) {
+    f();
+}
+
+fn main() {
+    let mut y = true;
+    foo(Box::new(use || y = !y) as Box<_>);
+    //~^ ERROR cannot assign to `y`, as it is not declared as mutable
+}

tests/ui/ergonomic-clones/closure/immutable-outer-variable.rs

@@ -0,0 +1,15 @@
+//@ run-rustfix
+
+// Point at the captured immutable outer variable
+
+#![feature(ergonomic_clones)]
+
+fn foo(mut f: Box<dyn FnMut()>) {
+    f();
+}
+
+fn main() {
+    let y = true;
+    foo(Box::new(use || y = !y) as Box<_>);
+    //~^ ERROR cannot assign to `y`, as it is not declared as mutable
+}

tests/ui/ergonomic-clones/closure/immutable-outer-variable.stderr

@@ -0,0 +1,14 @@
+error[E0594]: cannot assign to `y`, as it is not declared as mutable
+  --> $DIR/immutable-outer-variable.rs:13:25
+   |
+LL |     foo(Box::new(use || y = !y) as Box<_>);
+   |                         ^^^^^^ cannot assign
+   |
+help: consider changing this to be mutable
+   |
+LL |     let mut y = true;
+   |         +++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0594`.