Fix multiline pattern idempotency

librubyfmt/rubyfmt_lib.rb

@@ -415,6 +415,14 @@ def on_var_field(ident)
     super + start_end
   end
 
+  def on_aryptn(*_)
+    with_lineno { super }
+  end
+
+  def on_fndptn(*_)
+    with_lineno { super }
+  end
+
   def on_tlambda(*args)
     @tlambda_stack << lineno
     super

librubyfmt/src/format.rs

@@ -3408,8 +3408,14 @@ fn format_pattern(ps: &mut dyn ConcreteParserState, pattern_node: PatternNode) {
 
 fn format_aryptn(ps: &mut dyn ConcreteParserState, aryptn: Aryptn) {
     // Making this `mut` for
-    let Aryptn(_, maybe_collection_name, maybe_pre_star_list, maybe_star, maybe_post_star_list) =
-        aryptn;
+    let Aryptn(
+        _,
+        maybe_collection_name,
+        maybe_pre_star_list,
+        maybe_star,
+        maybe_post_star_list,
+        start_end,
+    ) = aryptn;
     if let Some(collection_name) = maybe_collection_name {
         format_var_ref(ps, collection_name);
     }
@@ -3441,10 +3447,11 @@ fn format_aryptn(ps: &mut dyn ConcreteParserState, aryptn: Aryptn) {
             }),
         );
     }));
+    ps.wind_dumping_comments_until_line(start_end.end_line());
 }
 
 fn format_fndptn(ps: &mut dyn ConcreteParserState, fndptn: Fndptn) {
-    let Fndptn(_, maybe_collection_name, pre_splat, values, post_splat) = fndptn;
+    let Fndptn(_, maybe_collection_name, pre_splat, values, post_splat, start_end) = fndptn;
     if let Some(collection_name) = maybe_collection_name {
         format_var_ref(ps, collection_name);
     }
@@ -3463,6 +3470,7 @@ fn format_fndptn(ps: &mut dyn ConcreteParserState, fndptn: Fndptn) {
             }),
         );
     }));
+    ps.wind_dumping_comments_until_line(start_end.end_line());
 }
 
 fn pattern_splat_as_expr(var_field: VarField) -> Expression {

librubyfmt/src/ripper_tree_types.rs

@@ -2436,6 +2436,7 @@ pub struct Aryptn(
     pub Option<Vec<ExpressionOrVarField>>, // list of values before the first *
     pub Option<VarField>, // "*" pattern
     pub Option<Vec<ExpressionOrVarField>>, // list of values the first *
+    pub StartEnd,
 );
 
 def_tag!(fndptn_tag, "fndptn");
@@ -2446,6 +2447,7 @@ pub struct Fndptn(
     pub VarField,                  // leading "*" pattern
     pub Vec<ExpressionOrVarField>, // inner values
     pub VarField,                  // trailing "*" pattern
+    pub StartEnd,
 );
 
 #[derive(RipperDeserialize, Debug, Clone)]