Add parens for new/instanceof with complex expression

This is not fully accurate because the rules for "new variables"
are different than the rules for dereferenceable LHS.

Author: nikic

lib/PhpParser/PrettyPrinter/Standard.php

@@ -387,7 +387,10 @@ protected function pExpr_BinaryOp_Coalesce(BinaryOp\Coalesce $node) {
     }
 
     protected function pExpr_Instanceof(Expr\Instanceof_ $node) {
-        return $this->pInfixOp(Expr\Instanceof_::class, $node->expr, ' instanceof ', $node->class);
+        list($precedence, $associativity) = $this->precedenceMap[Expr\Instanceof_::class];
+        return $this->pPrec($node->expr, $precedence, $associativity, -1)
+             . ' instanceof '
+             . $this->pNewVariable($node->class);
     }
 
     // Unary expressions
@@ -635,7 +638,8 @@ protected function pExpr_New(Expr\New_ $node) {
             $args = $node->args ? '(' . $this->pMaybeMultiline($node->args) . ')' : '';
             return 'new ' . $this->pClassCommon($node->class, $args);
         }
-        return 'new ' . $this->p($node->class) . '(' . $this->pMaybeMultiline($node->args) . ')';
+        return 'new ' . $this->pNewVariable($node->class)
+            . '(' . $this->pMaybeMultiline($node->args) . ')';
     }
 
     protected function pExpr_Clone(Expr\Clone_ $node) {
@@ -1008,6 +1012,11 @@ protected function pCallLhs(Node $node) {
         }
     }
 
+    protected function pNewVariable(Node $node) {
+        // TODO: This is not fully accurate.
+        return $this->pDereferenceLhs($node);
+    }
+
     /**
      * @param Node[] $nodes
      * @return bool

lib/PhpParser/PrettyPrinterAbstract.php

@@ -1127,7 +1127,7 @@ protected function initializeFixupMap() {
             Expr\PostDec::class => ['var' => self::FIXUP_PREC_LEFT],
             Expr\Instanceof_::class => [
                 'expr' => self::FIXUP_PREC_LEFT,
-                'class' => self::FIXUP_PREC_RIGHT,
+                'class' => self::FIXUP_PREC_RIGHT, // TODO: FIXUP_NEW_VARIABLE
             ],
             Expr\Ternary::class => [
                 'cond' => self::FIXUP_PREC_LEFT,
@@ -1137,6 +1137,8 @@ protected function initializeFixupMap() {
             Expr\FuncCall::class => ['name' => self::FIXUP_CALL_LHS],
             Expr\StaticCall::class => ['class' => self::FIXUP_DEREF_LHS],
             Expr\ArrayDimFetch::class => ['var' => self::FIXUP_DEREF_LHS],
+            Expr\ClassConstFetch::class => ['var' => self::FIXUP_DEREF_LHS],
+            Expr\New_::class => ['class' => self::FIXUP_DEREF_LHS], // TODO: FIXUP_NEW_VARIABLE
             Expr\MethodCall::class => [
                 'var' => self::FIXUP_DEREF_LHS,
                 'name' => self::FIXUP_BRACED_NAME,
@@ -1157,9 +1159,6 @@ protected function initializeFixupMap() {
                 'var' => self::FIXUP_DEREF_LHS,
                 'name' => self::FIXUP_BRACED_NAME,
             ],
-            Expr\ClassConstFetch::class => [
-                'var' => self::FIXUP_DEREF_LHS,
-            ],
             Scalar\Encapsed::class => [
                 'parts' => self::FIXUP_ENCAPSED,
             ],

test/code/prettyPrinter/expr/newVariable.test

@@ -0,0 +1,11 @@
+Parentheses for complex new/instanceof expressions
+-----
+<?php
+new ('a' . 'b');
+$x instanceof ('a' . 'b');
+$x instanceof ($y++);
+-----
+!!php7
+new ('a' . 'b')();
+$x instanceof ('a' . 'b');
+$x instanceof ($y++);