1 files changed, 3 insertions, 0 deletions
diff --git a/lib/output.js b/lib/output.js
index b33bc634..42b3aad9 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -1081,6 +1081,9 @@ function OutputStream(options) {
         if (output.option("ascii_only"))
             str = output.to_ascii(str);
         output.print(str);
+        var p = output.parent();
+        if (p instanceof AST_Binary && /^in/.test(p.operator) && p.left === self)
+            output.print(" ");
     });
 
     function force_statement(stat, output) {