Merge pull request #2966 from topecongiro/issue-2953

Format in-place expression like assignment

Author: nrc

src/expr.rs

@@ -338,8 +338,10 @@ pub fn format_expr(
                 ))
             }
         }
-        // FIXME(#2743)
-        ast::ExprKind::ObsoleteInPlace(..) => unimplemented!(),
+        ast::ExprKind::ObsoleteInPlace(ref lhs, ref rhs) => lhs
+            .rewrite(context, shape)
+            .map(|s| s + " <-")
+            .and_then(|lhs| rewrite_assign_rhs(context, lhs, &**rhs, shape)),
         ast::ExprKind::Async(capture_by, _node_id, ref block) => {
             let mover = if capture_by == ast::CaptureBy::Value {
                 "move "

src/lib.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tool_attributes)]
 #![feature(decl_macro)]
 #![allow(unused_attributes)]
 #![feature(type_ascription)]

tests/target/obsolete_in_place.rs

@@ -0,0 +1,9 @@
+// #2953
+
+macro_rules! demo {
+    ($a:ident <- $b:expr) => {};
+}
+
+fn main() {
+    demo!(i <- 0);
+}