Add two more tests for redundant_closure

These two cases were fixed by #4008.

Closes #1439

changelog: none

tests/ui/eta.fixed

@@ -98,6 +98,30 @@ fn test_redundant_closures_containing_method_calls() {
         t.iter().filter(|x| x.trait_foo_ref());
         t.iter().map(|x| x.trait_foo_ref());
     }
+
+    let mut some = Some(|x| x * x);
+    let arr = [Ok(1), Err(2)];
+    let _: Vec<_> = arr.iter().map(|x| x.map_err(some.take().unwrap())).collect();
+}
+
+struct Thunk<T>(Box<FnMut() -> T>);
+
+impl<T> Thunk<T> {
+    fn new<F: 'static + FnOnce() -> T>(f: F) -> Thunk<T> {
+        let mut option = Some(f);
+        // This should not trigger redundant_closure (#1439)
+        Thunk(Box::new(move || option.take().unwrap()()))
+    }
+
+    fn unwrap(self) -> T {
+        let Thunk(mut f) = self;
+        f()
+    }
+}
+
+fn foobar() {
+    let thunk = Thunk::new(|| println!("Hello, world!"));
+    thunk.unwrap()
 }
 
 fn meta<F>(f: F)

tests/ui/eta.rs

@@ -98,6 +98,30 @@ fn test_redundant_closures_containing_method_calls() {
         t.iter().filter(|x| x.trait_foo_ref());
         t.iter().map(|x| x.trait_foo_ref());
     }
+
+    let mut some = Some(|x| x * x);
+    let arr = [Ok(1), Err(2)];
+    let _: Vec<_> = arr.iter().map(|x| x.map_err(|e| some.take().unwrap()(e))).collect();
+}
+
+struct Thunk<T>(Box<FnMut() -> T>);
+
+impl<T> Thunk<T> {
+    fn new<F: 'static + FnOnce() -> T>(f: F) -> Thunk<T> {
+        let mut option = Some(f);
+        // This should not trigger redundant_closure (#1439)
+        Thunk(Box::new(move || option.take().unwrap()()))
+    }
+
+    fn unwrap(self) -> T {
+        let Thunk(mut f) = self;
+        f()
+    }
+}
+
+fn foobar() {
+    let thunk = Thunk::new(|| println!("Hello, world!"));
+    thunk.unwrap()
 }
 
 fn meta<F>(f: F)

tests/ui/eta.stderr

@@ -69,16 +69,22 @@ LL |     let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_as
    |                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove closure as shown: `char::to_ascii_uppercase`
 
 error: redundant closure found
-  --> $DIR/eta.rs:145:27
+  --> $DIR/eta.rs:104:50
+   |
+LL |     let _: Vec<_> = arr.iter().map(|x| x.map_err(|e| some.take().unwrap()(e))).collect();
+   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove closure as shown: `some.take().unwrap()`
+
+error: redundant closure found
+  --> $DIR/eta.rs:169:27
    |
 LL |     let a = Some(1u8).map(|a| foo_ptr(a));
    |                           ^^^^^^^^^^^^^^ help: remove closure as shown: `foo_ptr`
 
 error: redundant closure found
-  --> $DIR/eta.rs:150:27
+  --> $DIR/eta.rs:174:27
    |
 LL |     let a = Some(1u8).map(|a| closure(a));
    |                           ^^^^^^^^^^^^^^ help: remove closure as shown: `closure`
 
-error: aborting due to 13 previous errors
+error: aborting due to 14 previous errors