diff --git a/src/expr.rs b/src/expr.rs
index c9d704765c2..52b33ea1a26 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -1984,6 +1984,9 @@ pub(crate) fn rewrite_assign_rhs_with<S: Into<String>, R: Rewrite>(
 ) -> Option<String> {
     let lhs = lhs.into();
     let rhs = rewrite_assign_rhs_expr(context, &lhs, ex, shape, rhs_kind, rhs_tactics)?;
+    if context.config.version() == Version::Two && lhs.ends_with(" ") && rhs.starts_with(" ") {
+        return Some(lhs + &rhs.trim_start());
+    }
     Some(lhs + &rhs)
 }
 
diff --git a/tests/target/issue-5525.rs b/tests/target/issue-5525.rs
new file mode 100644
index 00000000000..e339b7e0526
--- /dev/null
+++ b/tests/target/issue-5525.rs
@@ -0,0 +1,9 @@
+// rustfmt-version: Two
+
+pub struct SomeCallback(
+    pub extern "C" fn(
+        long_argument_name_to_avoid_wrap: u32,
+        second_long_argument_name: u32,
+        third_long_argument_name: u32,
+    ),
+);