[dx] Add "if" set with if/else/ternary rules

[TomasVotruba]

Moves if-focused rules out of the code quality set into a dedicated SetList::IF set, also available via withPreparedSets(if: true).

The set groups rules that handle conditions on nullable/object/array values, if/else to ternary, ternary to if, and if merging - 10 rules in total. They are removed from CodeQualityLevel::RULES, so withCodeQualityLevel() positions shift accordingly.

use Rector\Config\RectorConfig;
use Rector\Set\ValueObject\SetList;

return RectorConfig::configure()
    ->withSets([SetList::IF]);

Rules and their changes

AlternativeIfToBracketRector - alternative syntax to brackets

-if ($value) :
-    $result = 1;
-else :
-    $result = 2;
-endif;
+if ($value) {
+    $result = 1;
+} else {
+    $result = 2;
+}

CompleteMissingIfElseBracketRector - complete missing brackets

-if ($value)
-    return 1;
+if ($value) {
+    return 1;
+}

InlineIfToExplicitIfRector - inline if to explicit if

-is_null($userId) && $userId = 5;
+if (is_null($userId)) {
+    $userId = 5;
+}

TernaryFalseExpressionToIfRector - ternary with false to if

-$value ? $someMethod->call($value) : false;
+if ($value) {
+    $someMethod->call($value);
+}

ArrayExplicitBoolCompareRector - explicit array condition

 public function run(array $items)
 {
-    if (! $items) {
+    if ($items === []) {
         return 'no items';
     }
 }

ObjectExplicitBoolCompareRector - explicit nullable object condition

 public function run(?\stdClass $item)
 {
-    if (! $item) {
+    if (! $item instanceof \stdClass) {
         return 'empty';
     }
 }

ExplicitBoolCompareRector - explicit bool condition

-if (! count($items)) {
+if (count($items) === 0) {
     return 'no items';
 }

CombineIfRector - merge nested ifs

-if ($cond1) {
-    if ($cond2) {
-        return 'foo';
-    }
+if ($cond1 && $cond2) {
+    return 'foo';
 }

ShortenElseIfRector - else + if to elseif

 if ($cond1) {
     return $action1;
-} else {
-    if ($cond2) {
-        return $action2;
-    }
+} elseif ($cond2) {
+    return $action2;
 }

SimplifyIfElseToTernaryRector - if/else assign to ternary

-if (empty($value)) {
-    $this->arrayBuilt[][$key] = true;
-} else {
-    $this->arrayBuilt[][$key] = $value;
-}
+$this->arrayBuilt[][$key] = empty($value) ? true : $value;