Teach rustfmt to handle postfix yield

Author: eholk

src/expr.rs

@@ -221,7 +221,7 @@ pub(crate) fn format_expr(
                 Ok(format!("break{id_str}"))
             }
         }
-        ast::ExprKind::Yield(ref opt_expr) => {
+        ast::ExprKind::Yield(ref opt_expr, ast::YieldKind::Prefix) => {
             if let Some(ref expr) = *opt_expr {
                 rewrite_unary_prefix(context, "yield ", &**expr, shape)
             } else {
@@ -243,7 +243,8 @@ pub(crate) fn format_expr(
         ast::ExprKind::Try(..)
         | ast::ExprKind::Field(..)
         | ast::ExprKind::MethodCall(..)
-        | ast::ExprKind::Await(_, _) => rewrite_chain(expr, context, shape),
+        | ast::ExprKind::Await(_, _)
+        | ast::ExprKind::Yield(_, ast::YieldKind::Postfix) => rewrite_chain(expr, context, shape),
         ast::ExprKind::MacCall(ref mac) => {
             rewrite_macro(mac, None, context, shape, MacroPosition::Expression).or_else(|_| {
                 wrap_str(

tests/source/postfix-yield.rs

@@ -0,0 +1,15 @@
+// This demonstrates a proposed alternate or additional option of having yield in postfix position.
+//@ edition: 2024
+
+#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr)]
+
+use std::ops::{Coroutine, CoroutineState};
+use std::pin::pin;
+
+fn main() {
+    let mut coro =
+        pin!(#[coroutine] |_: i32| { let x = 1.yield;
+            
+            
+             (x + 2).yield; });
+}

tests/target/postfix-yield.rs

@@ -0,0 +1,12 @@
+// This demonstrates a proposed alternate or additional option of having yield in postfix position.
+//@ edition: 2024
+
+#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr)]
+
+use std::ops::{Coroutine, CoroutineState};
+use std::pin::pin;
+
+fn main() {
+    let mut coro =
+        pin!(#[coroutine] |_: i32| { let x = 1.yield; (x + 2).yield; });
+}