Fix #4654 - consistent format of struct post-comments in new line - with and without trailing comma

Author: davidBar-On

src/lists.rs

@@ -616,7 +616,16 @@ pub(crate) fn extract_post_comment(
     let white_space: &[_] = &[' ', '\t'];
 
     // Cleanup post-comment: strip separators and whitespace.
-    let post_snippet = post_snippet[..comment_end].trim();
+    // If trimmed string starts with comment - preserve leading new-line.
+    let post_snippet_start_trimmed = post_snippet[..comment_end].trim_start();
+    let post_snippet = if post_snippet_start_trimmed.starts_with("//")
+        || post_snippet_start_trimmed.starts_with("/*")
+    {
+        post_snippet[..comment_end].trim_matches(white_space)
+    } else {
+        post_snippet_start_trimmed
+    }
+    .trim_end();
 
     let last_inline_comment_ends_with_separator = if is_last {
         if let Some(line) = post_snippet.lines().last() {

tests/source/issue-4654.rs

@@ -0,0 +1,127 @@
+// Struct comments that start in new line
+
+// No trailing comma
+
+struct Foo {
+bar: ()
+// Comment
+}
+
+struct Bar {
+baz: ()
+/*
+Comment
+*/
+}
+
+struct Baz(
+()
+// Comment
+);
+
+fn main() {
+let _ = Foo {
+bar: ()
+/*
+Comment
+*/
+};
+
+let _ = Bar {
+baz: ()
+/*
+Comment
+*/
+};
+
+let _ = Baz(
+()
+// Comment
+);
+}
+
+// With trailing comma
+
+struct Foo {
+bar: (),
+// Comment
+}
+
+struct Bar {
+baz: (),
+/*
+Comment
+*/
+}
+
+struct Baz(
+(),
+// Comment
+);
+
+fn main() {
+let _ = Foo {
+bar: (),
+/*
+Comment
+*/
+};
+
+let _ = Bar {
+baz: (),
+/*
+Comment
+*/
+};
+
+let _ = Baz(
+(),
+// Comment
+);
+}
+
+// With new line before trailing comma
+
+struct Foo {
+bar: ()
+,
+// Comment
+}
+
+struct Bar {
+baz: ()
+,
+/*
+Comment
+*/
+}
+
+struct Baz(
+()
+,
+// Comment
+);
+
+fn main() {
+let _ = Foo {
+bar: ()
+,
+/*
+Comment
+*/
+};
+
+let _ = Bar {
+baz: ()
+,
+/*
+Comment
+*/
+};
+
+let _ = Baz(
+()
+,
+// Comment
+);
+}

tests/target/issue-3198.rs

@@ -1,15 +1,31 @@
 impl TestTrait {
     fn foo_one_pre(/* Important comment1 */ self) {}
 
-    fn foo_one_post(self /* Important comment1 */) {}
+    fn foo_one_post(
+        self,
+        /* Important comment1 */
+    ) {
+    }
 
     fn foo_pre(/* Important comment1 */ self, /* Important comment2 */ a: i32) {}
 
-    fn foo_post(self /* Important comment1 */, a: i32 /* Important comment2 */) {}
+    fn foo_post(
+        self,
+        /* Important comment1 */
+        a: i32,
+        /* Important comment2 */
+    ) {
+    }
 
     fn bar_pre(/* Important comment1 */ &mut self, /* Important comment2 */ a: i32) {}
 
-    fn bar_post(&mut self /* Important comment1 */, a: i32 /* Important comment2 */) {}
+    fn bar_post(
+        &mut self,
+        /* Important comment1 */
+        a: i32,
+        /* Important comment2 */
+    ) {
+    }
 
     fn baz_pre(
         /* Important comment1 */
@@ -20,8 +36,10 @@ impl TestTrait {
     }
 
     fn baz_post(
-        self: X<'a, 'b>, /* Important comment1 */
-        a: i32,          /* Important comment2 */
+        self: X<'a, 'b>,
+        /* Important comment1 */
+        a: i32,
+        /* Important comment2 */
     ) {
     }
 
@@ -36,9 +54,12 @@ impl TestTrait {
     }
 
     fn baz_tree_post(
-        self: X<'a, 'b>, /* Important comment1 */
-        a: i32,          /* Important comment2 */
-        b: i32,          /* Important comment3 */
+        self: X<'a, 'b>,
+        /* Important comment1 */
+        a: i32,
+        /* Important comment2 */
+        b: i32,
+        /* Important comment3 */
     ) {
     }
 

tests/target/issue-3532.rs

@@ -1,6 +1,7 @@
 fn foo(a: T) {
     match a {
         1 => {}
-        0 => {} // _ => panic!("doesn't format!"),
+        0 => {}
+        // _ => panic!("doesn't format!"),
     }
 }

tests/target/issue-3675.rs

@@ -1,6 +1,7 @@
 fn main() {
     println!(
-        "{}", // comment
+        "{}",
+        // comment
         111
     );
 }

tests/target/issue-4654.rs

@@ -0,0 +1,121 @@
+// Struct comments that start in new line
+
+// No trailing comma
+
+struct Foo {
+    bar: (),
+    // Comment
+}
+
+struct Bar {
+    baz: (),
+    /*
+    Comment
+    */
+}
+
+struct Baz(
+    (),
+    // Comment
+);
+
+fn main() {
+    let _ = Foo {
+        bar: (),
+        /*
+        Comment
+        */
+    };
+
+    let _ = Bar {
+        baz: (),
+        /*
+        Comment
+        */
+    };
+
+    let _ = Baz(
+        (),
+        // Comment
+    );
+}
+
+// With trailing comma
+
+struct Foo {
+    bar: (),
+    // Comment
+}
+
+struct Bar {
+    baz: (),
+    /*
+    Comment
+    */
+}
+
+struct Baz(
+    (),
+    // Comment
+);
+
+fn main() {
+    let _ = Foo {
+        bar: (),
+        /*
+        Comment
+        */
+    };
+
+    let _ = Bar {
+        baz: (),
+        /*
+        Comment
+        */
+    };
+
+    let _ = Baz(
+        (),
+        // Comment
+    );
+}
+
+// With new line before trailing comma
+
+struct Foo {
+    bar: (),
+    // Comment
+}
+
+struct Bar {
+    baz: (),
+    /*
+    Comment
+    */
+}
+
+struct Baz(
+    (),
+    // Comment
+);
+
+fn main() {
+    let _ = Foo {
+        bar: (),
+        /*
+        Comment
+        */
+    };
+
+    let _ = Bar {
+        baz: (),
+        /*
+        Comment
+        */
+    };
+
+    let _ = Baz(
+        (),
+        // Comment
+    );
+}

tests/target/issue-5042/multi-line_comment_with_trailing_comma.rs

@@ -2,23 +2,27 @@ fn main() {
     // 5042 deals with trailing commas, not the indentation issue of these comments
     // When a future PR fixes the inentation issues these test can be updated
     let _ = std::ops::Add::add(
-        10, 20, // ...
-           // ...,
+        10, 20,
+        // ...
+        // ...,
     );
 
     let _ = std::ops::Add::add(
-        10, 20, /* ... */
-           // ...,
+        10, 20,
+        /* ... */
+        // ...,
     );
 
     let _ = std::ops::Add::add(
-        10, 20, // ...,
-           // ...,
+        10, 20,
+        // ...,
+        // ...,
     );
 
     let _ = std::ops::Add::add(
-        10, 20, // ...,
-           /* ...
-            */
+        10, 20,
+        // ...,
+        /* ...
+         */
     );
 }