Add gen blocks to ast and do some broken ast lowering

src/closures.rs

@@ -188,7 +188,7 @@ fn rewrite_closure_expr(
     fn allow_multi_line(expr: &ast::Expr) -> bool {
         match expr.kind {
             ast::ExprKind::Match(..)
-            | ast::ExprKind::Async(..)
+            | ast::ExprKind::Gen(..)
             | ast::ExprKind::Block(..)
             | ast::ExprKind::TryBlock(..)
             | ast::ExprKind::Loop(..)

src/expr.rs

@@ -367,7 +367,7 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
                 ))
             }
         }
-        ast::ExprKind::Async(capture_by, ref block) => {
+        ast::ExprKind::Gen(capture_by, ref block, ref kind) => {
             let mover = if capture_by == ast::CaptureBy::Value {
                 "move "
             } else {
@@ -375,7 +375,7 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
             };
             if let rw @ Some(_) = rewrite_single_line_block(
                 context,
-                format!("async {mover}").as_str(),
+                format!("{kind} {mover}").as_str(),
                 block,
                 Some(&expr.attrs),
                 None,
@@ -386,7 +386,7 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
                 // 6 = `async `
                 let budget = shape.width.saturating_sub(6);
                 Some(format!(
-                    "async {mover}{}",
+                    "{kind} {mover}{}",
                     rewrite_block(
                         block,
                         Some(&expr.attrs),
@@ -1371,7 +1371,7 @@ pub(crate) fn can_be_overflowed_expr(
         }
 
         // Handle always block-like expressions
-        ast::ExprKind::Async(..) | ast::ExprKind::Block(..) | ast::ExprKind::Closure(..) => true,
+        ast::ExprKind::Gen(..) | ast::ExprKind::Block(..) | ast::ExprKind::Closure(..) => true,
 
         // Handle `[]` and `{}`-like expressions
         ast::ExprKind::Array(..) | ast::ExprKind::Struct(..) => {

src/utils.rs

@@ -473,7 +473,7 @@ pub(crate) fn is_block_expr(context: &RewriteContext<'_>, expr: &ast::Expr, repr
         | ast::ExprKind::If(..)
         | ast::ExprKind::Block(..)
         | ast::ExprKind::ConstBlock(..)
-        | ast::ExprKind::Async(..)
+        | ast::ExprKind::Gen(..)
         | ast::ExprKind::Loop(..)
         | ast::ExprKind::ForLoop(..)
         | ast::ExprKind::TryBlock(..)