redundant_closure ignore coerced closure

tests/ui/eta.fixed

@@ -37,7 +37,7 @@ fn main() {
     }
 
     // See #815
-    let e = Some(1u8).map(divergent);
+    let e = Some(1u8).map(|a| divergent(a));
     let e = Some(1u8).map(generic);
     let e = Some(1u8).map(generic);
     // See #515
@@ -233,7 +233,7 @@ fn late_bound_lifetimes() {
     {
     }
     map_str(|s| take_asref_path(s));
-    map_str_to_path(std::convert::AsRef::as_ref);
+    map_str_to_path(|s| s.as_ref());
 }
 
 mod type_param_bound {
@@ -279,3 +279,15 @@ mod bind_by_ref {
         Some(A).map(|ref a| B::from(a));
     }
 }
+
+// #7812 False positive on coerced closure
+fn coerced_closure() {
+    fn function_returning_unit<F: FnMut(i32)>(f: F) {}
+    function_returning_unit(|x| std::process::exit(x));
+
+    fn arr() -> &'static [u8; 0] {
+        &[]
+    }
+    fn slice_fn(_: impl FnOnce() -> &'static [u8]) {}
+    slice_fn(|| arr());
+}

tests/ui/eta.rs

@@ -279,3 +279,15 @@ mod bind_by_ref {
         Some(A).map(|ref a| B::from(a));
     }
 }
+
+// #7812 False positive on coerced closure
+fn coerced_closure() {
+    fn function_returning_unit<F: FnMut(i32)>(f: F) {}
+    function_returning_unit(|x| std::process::exit(x));
+
+    fn arr() -> &'static [u8; 0] {
+        &[]
+    }
+    fn slice_fn(_: impl FnOnce() -> &'static [u8]) {}
+    slice_fn(|| arr());
+}

tests/ui/eta.stderr

@@ -24,12 +24,6 @@ error: redundant closure
 LL |     all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted
    |                          ^^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `below`
 
-error: redundant closure
-  --> $DIR/eta.rs:40:27
-   |
-LL |     let e = Some(1u8).map(|a| divergent(a));
-   |                           ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `divergent`
-
 error: redundant closure
   --> $DIR/eta.rs:41:27
    |
@@ -122,11 +116,5 @@ error: redundant closure
 LL |         Some(1).map(|n| in_loop(n));
    |                     ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `in_loop`
 
-error: redundant closure
-  --> $DIR/eta.rs:236:21
-   |
-LL |     map_str_to_path(|s| s.as_ref());
-   |                     ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::convert::AsRef::as_ref`
-
-error: aborting due to 21 previous errors
+error: aborting due to 19 previous errors