Handle arbitrary expression types in aref_field nodes (#381)

* Fixtures

* Handle all expression lists in aref fields

* Add fixtures for non-assign arefs

* Fix multiline item rendering for expressions with hard newlines in them

fixtures/small/aref_field_actual.rb

@@ -1,3 +1,23 @@
 # As above
 a[0] = b
 # So below
+
+a[puts a] = ""
+a[puts(a)] = ""
+a[()] = ""
+a[class A; def foo; puts a; end; end] = ""
+a[begin; ""; rescue StandardException; ""; end] = ""
+# Users can override #[]= to not have args
+a[] = ""
+# Users can override #[]= to have multiple args
+a[1, 2] = ""
+
+a[puts a]
+a[puts(a)]
+a[()]
+a[class A; def foo; puts a; end; end]
+a[begin; ""; rescue StandardException; ""; end]
+# Users can override #[] to not have args
+a[]
+# Users can override #[] to have multiple args
+a[1, 2]

fixtures/small/aref_field_expected.rb

@@ -1,3 +1,47 @@
 # As above
 a[0] = b
 # So below
+
+a[puts(a)] = ""
+a[puts(a)] = ""
+a[()] = ""
+a[
+  class A
+    def foo
+      puts(a)
+    end
+  end
+] = ""
+a[
+  begin
+    ""
+  rescue StandardException
+    ""
+  end
+] = ""
+# Users can override #[]= to not have args
+a[] = ""
+# Users can override #[]= to have multiple args
+a[1, 2] = ""
+
+a[puts(a)]
+a[puts(a)]
+a[()]
+a[
+  class A
+    def foo
+      puts(a)
+    end
+  end
+]
+a[
+  begin
+    ""
+  rescue StandardException
+    ""
+  end
+]
+# Users can override #[] to not have args
+a[]
+# Users can override #[] to have multiple args
+a[1, 2]

librubyfmt/src/format.rs

@@ -1755,19 +1755,18 @@ pub fn format_aref_field(ps: &mut dyn ConcreteParserState, af: ArefField) {
         false,
         Box::new(|ps| {
             format_expression(ps, *af.1);
-            let aab = af.2;
-            match aab.2 {
-                ToProcExpr::Present(_) => {
-                    panic!("got a to_proc in an aref_field, should be impossible");
-                }
-                ToProcExpr::NotPresent(_) => {
-                    format_array_fast_path(
-                        ps,
-                        end_line,
-                        Some((aab.1).into_args_add_star_or_expression_list()),
-                    );
+
+            let index_expr = af.2;
+            let arr_contents = match index_expr {
+                None => None,
+                Some(ArgsAddBlockOrExpressionList::ArgsAddBlock(aab)) => {
+                    Some(aab.1.into_args_add_star_or_expression_list())
                 }
-            }
+                Some(ArgsAddBlockOrExpressionList::ExpressionList(expr_list)) => Some(
+                    ArgsAddStarOrExpressionListOrArgsForward::ExpressionList(expr_list),
+                ),
+            };
+            format_array_fast_path(ps, end_line, arr_contents);
         }),
     );
 
@@ -2299,7 +2298,12 @@ fn format_constant_body(ps: &mut dyn ConcreteParserState, bodystmt: Box<BodyStmt
     }));
 
     ps.on_line(end_line);
-    ps.emit_end();
+    ps.with_start_of_line(
+        true,
+        Box::new(|ps| {
+            ps.emit_end();
+        }),
+    );
     if ps.at_start_of_line() {
         ps.emit_newline();
     }

librubyfmt/src/render_targets.rs

@@ -1,5 +1,5 @@
 use crate::delimiters::BreakableDelims;
-use crate::line_tokens::{AbstractLineToken, ConcreteLineTokenAndTargets};
+use crate::line_tokens::{AbstractLineToken, ConcreteLineToken, ConcreteLineTokenAndTargets};
 use crate::parser_state::FormattingContext;
 use crate::types::{ColNumber, LineNumber};
 use std::collections::HashSet;
@@ -144,7 +144,9 @@ impl AbstractTokenTarget for BreakableEntry {
     }
 
     fn is_multiline(&self) -> bool {
-        self.line_numbers.len() > 1 || self.any_collapsing_newline_has_heredoc_content()
+        self.line_numbers.len() > 1
+            || self.any_collapsing_newline_has_heredoc_content()
+            || self.contains_hard_newline()
     }
 
     fn len(&self) -> usize {
@@ -177,4 +179,13 @@ impl BreakableEntry {
             _ => false,
         })
     }
+
+    fn contains_hard_newline(&self) -> bool {
+        self.tokens.iter().any(|t| {
+            matches!(
+                t,
+                AbstractLineToken::ConcreteLineToken(ConcreteLineToken::HardNewLine)
+            )
+        })
+    }
 }

librubyfmt/src/ripper_tree_types.rs

@@ -431,7 +431,7 @@ def_tag!(aref_field_tag, "aref_field");
 pub struct ArefField(
     pub aref_field_tag,
     pub Box<Expression>,
-    pub ArgsAddBlock,
+    pub Option<ArgsAddBlockOrExpressionList>,
     pub LineCol,
 );