diff --git a/tests/ui/explicit_auto_deref.fixed b/tests/ui/explicit_auto_deref.fixed
index d4a9aa7e46c..d4ff1b1566d 100644
--- a/tests/ui/explicit_auto_deref.fixed
+++ b/tests/ui/explicit_auto_deref.fixed
@@ -59,6 +59,10 @@ fn f_str_t<T>(_: &str, _: T) {}
 
 fn f_box_t<T>(_: &Box<T>) {}
 
+extern "C" {
+    fn var(_: u32, ...);
+}
+
 fn main() {
     let s = String::new();
 
@@ -202,4 +206,9 @@ fn main() {
 
     f_str(&&ref_str); // `needless_borrow` will suggest removing both references
     f_str(&ref_str); // `needless_borrow` will suggest removing only one reference
+
+    let x = &&40;
+    unsafe {
+        var(0, &**x);
+    }
 }
diff --git a/tests/ui/explicit_auto_deref.rs b/tests/ui/explicit_auto_deref.rs
index 243b8e919c6..99294a7947b 100644
--- a/tests/ui/explicit_auto_deref.rs
+++ b/tests/ui/explicit_auto_deref.rs
@@ -59,6 +59,10 @@ fn f_str_t<T>(_: &str, _: T) {}
 
 fn f_box_t<T>(_: &Box<T>) {}
 
+extern "C" {
+    fn var(_: u32, ...);
+}
+
 fn main() {
     let s = String::new();
 
@@ -202,4 +206,9 @@ fn main() {
 
     f_str(&&*ref_str); // `needless_borrow` will suggest removing both references
     f_str(&&**ref_str); // `needless_borrow` will suggest removing only one reference
+
+    let x = &&40;
+    unsafe {
+        var(0, &**x);
+    }
 }
diff --git a/tests/ui/explicit_auto_deref.stderr b/tests/ui/explicit_auto_deref.stderr
index 19435eab96b..55f956e37ae 100644
--- a/tests/ui/explicit_auto_deref.stderr
+++ b/tests/ui/explicit_auto_deref.stderr
@@ -1,5 +1,5 @@
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:65:20
+  --> $DIR/explicit_auto_deref.rs:69:20
    |
 LL |     let _: &str = &*s;
    |                    ^^ help: try this: `s`
@@ -7,187 +7,187 @@ LL |     let _: &str = &*s;
    = note: `-D clippy::explicit-auto-deref` implied by `-D warnings`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:69:12
+  --> $DIR/explicit_auto_deref.rs:73:12
    |
 LL |     f_str(&*s);
    |            ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:73:14
+  --> $DIR/explicit_auto_deref.rs:77:14
    |
 LL |     f_str_t(&*s, &*s); // Don't lint second param.
    |              ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:76:25
+  --> $DIR/explicit_auto_deref.rs:80:25
    |
 LL |     let _: &Box<i32> = &**b;
    |                         ^^^ help: try this: `b`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:82:8
+  --> $DIR/explicit_auto_deref.rs:86:8
    |
 LL |     c(&*s);
    |        ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:88:9
+  --> $DIR/explicit_auto_deref.rs:92:9
    |
 LL |         &**x
    |         ^^^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:92:11
+  --> $DIR/explicit_auto_deref.rs:96:11
    |
 LL |         { &**x }
    |           ^^^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:96:9
+  --> $DIR/explicit_auto_deref.rs:100:9
    |
 LL |         &**{ x }
    |         ^^^^^^^^ help: try this: `{ x }`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:100:9
+  --> $DIR/explicit_auto_deref.rs:104:9
    |
 LL |         &***x
    |         ^^^^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:117:13
+  --> $DIR/explicit_auto_deref.rs:121:13
    |
 LL |         f1(&*x);
    |             ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:118:13
+  --> $DIR/explicit_auto_deref.rs:122:13
    |
 LL |         f2(&*x);
    |             ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:119:13
+  --> $DIR/explicit_auto_deref.rs:123:13
    |
 LL |         f3(&*x);
    |             ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:120:28
+  --> $DIR/explicit_auto_deref.rs:124:28
    |
 LL |         f4.callable_str()(&*x);
    |                            ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:121:13
+  --> $DIR/explicit_auto_deref.rs:125:13
    |
 LL |         f5(&*x);
    |             ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:122:13
+  --> $DIR/explicit_auto_deref.rs:126:13
    |
 LL |         f6(&*x);
    |             ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:123:28
+  --> $DIR/explicit_auto_deref.rs:127:28
    |
 LL |         f7.callable_str()(&*x);
    |                            ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:124:26
+  --> $DIR/explicit_auto_deref.rs:128:26
    |
 LL |         f8.callable_t()(&*x);
    |                          ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:125:13
+  --> $DIR/explicit_auto_deref.rs:129:13
    |
 LL |         f9(&*x);
    |             ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:126:14
+  --> $DIR/explicit_auto_deref.rs:130:14
    |
 LL |         f10(&*x);
    |              ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:127:27
+  --> $DIR/explicit_auto_deref.rs:131:27
    |
 LL |         f11.callable_t()(&*x);
    |                           ^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:131:17
+  --> $DIR/explicit_auto_deref.rs:135:17
    |
 LL |     let _ = S1(&*s);
    |                 ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:136:22
+  --> $DIR/explicit_auto_deref.rs:140:22
    |
 LL |     let _ = S2 { s: &*s };
    |                      ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:152:30
+  --> $DIR/explicit_auto_deref.rs:156:30
    |
 LL |             let _ = Self::S1(&**s);
    |                              ^^^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:153:35
+  --> $DIR/explicit_auto_deref.rs:157:35
    |
 LL |             let _ = Self::S2 { s: &**s };
    |                                   ^^^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:156:21
+  --> $DIR/explicit_auto_deref.rs:160:21
    |
 LL |     let _ = E1::S1(&*s);
    |                     ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:157:26
+  --> $DIR/explicit_auto_deref.rs:161:26
    |
 LL |     let _ = E1::S2 { s: &*s };
    |                          ^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:175:13
+  --> $DIR/explicit_auto_deref.rs:179:13
    |
 LL |     let _ = (*b).foo;
    |             ^^^^ help: try this: `b`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:176:13
+  --> $DIR/explicit_auto_deref.rs:180:13
    |
 LL |     let _ = (**b).foo;
    |             ^^^^^ help: try this: `b`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:191:19
+  --> $DIR/explicit_auto_deref.rs:195:19
    |
 LL |     let _ = f_str(*ref_str);
    |                   ^^^^^^^^ help: try this: `ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:193:19
+  --> $DIR/explicit_auto_deref.rs:197:19
    |
 LL |     let _ = f_str(**ref_ref_str);
    |                   ^^^^^^^^^^^^^ help: try this: `ref_ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:203:13
+  --> $DIR/explicit_auto_deref.rs:207:13
    |
 LL |     f_str(&&*ref_str); // `needless_borrow` will suggest removing both references
    |             ^^^^^^^^ help: try this: `ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:204:12
+  --> $DIR/explicit_auto_deref.rs:208:12
    |
 LL |     f_str(&&**ref_str); // `needless_borrow` will suggest removing only one reference
    |            ^^^^^^^^^^ help: try this: `ref_str`