From d23c334707408057915a706351ac32b2db09d8c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Le=C3=B3n=20Orell=20Valerian=20Liehr?= <me@fmease.dev>
Date: Sat, 24 Jun 2023 23:39:35 +0200
Subject: [PATCH] rustdoc: get rid of extra line when line-wrapping fn decls
 with empty arg list

---
 src/librustdoc/html/format.rs                        |  2 +-
 .../decl-line-wrapping-empty-arg-list.decl.html      |  2 ++
 tests/rustdoc/decl-line-wrapping-empty-arg-list.rs   | 12 ++++++++++++
 3 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 tests/rustdoc/decl-line-wrapping-empty-arg-list.decl.html
 create mode 100644 tests/rustdoc/decl-line-wrapping-empty-arg-list.rs

diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index b710311c85872..b4aba2993c7fd 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -1408,7 +1408,7 @@ impl clean::FnDecl {
         let amp = if f.alternate() { "&" } else { "&amp;" };
 
         write!(f, "(")?;
-        if let Some(n) = line_wrapping_indent {
+        if let Some(n) = line_wrapping_indent && !self.inputs.values.is_empty() {
             write!(f, "\n{}", Indent(n + 4))?;
         }
         for (i, input) in self.inputs.values.iter().enumerate() {
diff --git a/tests/rustdoc/decl-line-wrapping-empty-arg-list.decl.html b/tests/rustdoc/decl-line-wrapping-empty-arg-list.decl.html
new file mode 100644
index 0000000000000..29c08c5bd5dec
--- /dev/null
+++ b/tests/rustdoc/decl-line-wrapping-empty-arg-list.decl.html
@@ -0,0 +1,2 @@
+<pre class="rust item-decl"><code>pub fn create(
+) -&gt; <a class="struct" href="struct.Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000.html" title="struct decl_line_wrapping_empty_arg_list::Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000">Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000</a></code></pre>
\ No newline at end of file
diff --git a/tests/rustdoc/decl-line-wrapping-empty-arg-list.rs b/tests/rustdoc/decl-line-wrapping-empty-arg-list.rs
new file mode 100644
index 0000000000000..4cfb87496b486
--- /dev/null
+++ b/tests/rustdoc/decl-line-wrapping-empty-arg-list.rs
@@ -0,0 +1,12 @@
+// Ensure that we don't add an extra line containing nothing but whitespace in between the two
+// parentheses of an empty argument list when line-wrapping a function declaration.
+
+// ignore-tidy-linelength
+
+pub struct Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000;
+
+// @has 'decl_line_wrapping_empty_arg_list/fn.create.html'
+// @snapshot decl - '//pre[@class="rust item-decl"]'
+pub fn create() -> Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000 {
+    loop {}
+}