Check if there are printable attributes in pipe.

Author: cristianoc

src/res_printer.ml

@@ -3651,7 +3651,9 @@ and printBinaryExpression ~customLayout (expr : Parsetree.expression) cmtTbl =
         [(Nolabel, lhs); (Nolabel, rhs)] )
     when not
            (ParsetreeViewer.isBinaryExpression lhs
-           || ParsetreeViewer.isBinaryExpression rhs) ->
+           || ParsetreeViewer.isBinaryExpression rhs
+           || printAttributes ~customLayout expr.pexp_attributes cmtTbl
+              <> Doc.nil) ->
     let lhsHasCommentBelow = hasCommentBelow cmtTbl lhs.pexp_loc in
     let lhsDoc = printOperand ~isLhs:true lhs op in
     let rhsDoc = printOperand ~isLhs:false rhs op in

tests/printer/expr/expected/pipe.res.txt

@@ -1,7 +1,7 @@
-let s1 = @ann x->foo
+let s1 = @ann (x->foo)
 let s1b = (@ann x)->foo
 
-let s2 = @ann x |> foo
+let s2 = @ann (x |> foo)
 let s2b = (@ann x) |> foo
 
 let s3 = @ann (x ** foo)