Insert parentheses when adding argument to new

Fixes the issue reported in #1134.

Author: nikic

lib/PhpParser/PrettyPrinterAbstract.php

@@ -1006,9 +1006,25 @@ protected function pArray(
 
  list($findToken, $extraLeft, $extraRight) = $this->emptyListInsertionMap[$mapKey];
  if (null !== $findToken) {
- $insertPos = $this->origTokens->findRight($pos, $findToken) + 1;
- $result .= $this->origTokens->getTokenCode($pos, $insertPos, $indentAdjustment);
- $pos = $insertPos;
+ // For anon classes skip to the class keyword.
+ $isAnonClassArgs = $mapKey === PrintableNewAnonClassNode::class . '->args';
+ if ($isAnonClassArgs) {
+ $insertPos = $this->origTokens->findRight($pos, \T_CLASS) + 1;
+ $result .= $this->origTokens->getTokenCode($pos, $insertPos, $indentAdjustment);
+ $pos = $insertPos;
+ }
+
+ // If "new Foo" was used without arguments, we need to convert to "new Foo()".
+ if (($mapKey === Expr\New_::class . '->args' || $isAnonClassArgs) &&
+ !$this->origTokens->haveTokenImmediatelyAfter($pos - 1, '(')
+ ) {
+ $extraLeft = '(';
+ $extraRight = ')';
+ } else {
+ $insertPos = $this->origTokens->findRight($pos, $findToken) + 1;
+ $result .= $this->origTokens->getTokenCode($pos, $insertPos, $indentAdjustment);
+ $pos = $insertPos;
+ }
  }
 
  $first = true;

test/code/formatPreservation/emptyListInsertion.test

@@ -108,3 +108,29 @@ Foo
 new class
 ($a, $b)
 extends Foo {};
+-----
+<?php
+new Foo;
+new Foo ;
+new Foo();
+new Foo ();
+new class {};
+new class() {};
+new class () {};
+-----
+$stmts[0]->expr->args[] = new Node\Expr\Variable('a');
+$stmts[1]->expr->args[] = new Node\Expr\Variable('a');
+$stmts[2]->expr->args[] = new Node\Expr\Variable('a');
+$stmts[3]->expr->args[] = new Node\Expr\Variable('a');
+$stmts[4]->expr->args[] = new Node\Expr\Variable('a');
+$stmts[5]->expr->args[] = new Node\Expr\Variable('a');
+$stmts[6]->expr->args[] = new Node\Expr\Variable('a');
+-----
+<?php
+new Foo($a);
+new Foo($a) ;
+new Foo($a);
+new Foo ($a);
+new class($a) {};
+new class($a) {};
+new class ($a) {};