Prevent merging of consecutive -/+ more thoroughly

The unary -/+ or --/++ might not be the direct child. Instead
determine this by actually printing the operand and checking
whether it starts with -/+.

lib/PhpParser/PrettyPrinter/Standard.php

@@ -428,18 +428,10 @@ class Standard extends PrettyPrinterAbstract {
     }
 
     protected function pExpr_UnaryMinus(Expr\UnaryMinus $node, int $precedence, int $lhsPrecedence): string {
-        if ($node->expr instanceof Expr\UnaryMinus || $node->expr instanceof Expr\PreDec) {
-            // Enforce -(-$expr) instead of --$expr
-            return '-(' . $this->p($node->expr) . ')';
-        }
         return $this->pPrefixOp(Expr\UnaryMinus::class, '-', $node->expr, $precedence, $lhsPrecedence);
     }
 
     protected function pExpr_UnaryPlus(Expr\UnaryPlus $node, int $precedence, int $lhsPrecedence): string {
-        if ($node->expr instanceof Expr\UnaryPlus || $node->expr instanceof Expr\PreInc) {
-            // Enforce +(+$expr) instead of ++$expr
-            return '+(' . $this->p($node->expr) . ')';
-        }
         return $this->pPrefixOp(Expr\UnaryPlus::class, '+', $node->expr, $precedence, $lhsPrecedence);
     }
 

lib/PhpParser/PrettyPrinterAbstract.php

@@ -378,7 +378,14 @@ abstract class PrettyPrinterAbstract {
             $suffix = ')';
             $lhsPrecedence = self::MAX_PRECEDENCE;
         }
-        return $prefix . $operatorString . $this->p($node, $opPrecedence, $lhsPrecedence) . $suffix;
+        $printedArg = $this->p($node, $opPrecedence, $lhsPrecedence);
+        if (($operatorString === '+' && $printedArg[0] === '+') ||
+            ($operatorString === '-' && $printedArg[0] === '-')
+        ) {
+            // Avoid printing +(+$a) as ++$a and similar.
+            $printedArg = '(' . $printedArg . ')';
+        }
+        return $prefix . $operatorString . $printedArg . $suffix;
     }
 
     /**

test/code/prettyPrinter/expr/parentheses.test

@@ -44,6 +44,8 @@ clone ($a + $b);
 +(+$a);
 -(--$a);
 +(++$a);
+-(--$a)**$b;
++(++$a)**$b;
 
 !$a = $b;
 ++$a ** $b;
@@ -90,6 +92,8 @@ clone ($a + $b);
 +(+$a);
 -(--$a);
 +(++$a);
+-(--$a ** $b);
++(++$a ** $b);
 !$a = $b;
 ++$a ** $b;
 $a ** $b++;