diff --git a/src/librustdoc/clean/simplify.rs b/src/librustdoc/clean/simplify.rs
index 73bc0386326ce..853170542e083 100644
--- a/src/librustdoc/clean/simplify.rs
+++ b/src/librustdoc/clean/simplify.rs
@@ -118,7 +118,7 @@ pub fn merge_bounds(
                 });
             }
             PP::Parenthesized { ref mut output, .. } => match output {
-                Some(o) => assert!(o == rhs),
+                Some(o) => assert_eq!(o, rhs),
                 None => if *rhs != clean::Type::Tuple(Vec::new()) {
                     *output = Some(rhs.clone());
                 }
diff --git a/src/test/rustdoc/auxiliary/issue-57180.rs b/src/test/rustdoc/auxiliary/issue-57180.rs
new file mode 100644
index 0000000000000..4e2f4b87c020e
--- /dev/null
+++ b/src/test/rustdoc/auxiliary/issue-57180.rs
@@ -0,0 +1,16 @@
+// compile-flags: -Cmetadata=aux
+
+pub trait Trait {
+}
+
+pub struct Struct<F>
+{
+    _p: ::std::marker::PhantomData<F>,
+}
+
+impl<F: Fn() -> u32>
+Trait for Struct<F>
+    where
+        F: Fn() -> u32,
+{
+}
diff --git a/src/test/rustdoc/issue-57180.rs b/src/test/rustdoc/issue-57180.rs
new file mode 100644
index 0000000000000..14bd2b0fec0d5
--- /dev/null
+++ b/src/test/rustdoc/issue-57180.rs
@@ -0,0 +1,7 @@
+// aux-build:issue-57180.rs
+
+extern crate issue_57180;
+use issue_57180::Trait;
+
+fn main() {
+}