Allow array unpacking in ArrayDeclaration multiline Sniff

src/Standards/Squiz/Sniffs/Arrays/ArrayDeclarationSniff.php

@@ -430,9 +430,22 @@ public function processMultiLineArray($phpcsFile, $stackPtr, $arrayStart, $array
                 }
 
                 if ($keyUsed === true && $tokens[$lastToken]['code'] === T_COMMA) {
-                    $error = 'No key specified for array entry; first entry specifies key';
-                    $phpcsFile->addError($error, $nextToken, 'NoKeySpecified');
-                    return;
+                    $nextToken = $phpcsFile->findNext(Tokens::$emptyTokens, ($lastToken + 1), null, true);
+
+                    /*
+                        Allow array unpacking
+
+                        $x = [
+                          'foo' => 'bar',
+                          ...$baz,
+                        ];
+                    */
+
+                    if ($tokens[$nextToken]['code'] !== T_ELLIPSIS) {
+                        $error = 'No key specified for array entry; first entry specifies key';
+                        $phpcsFile->addError($error, $nextToken, 'NoKeySpecified');
+                        return;
+                    }
                 }
 
                 if ($keyUsed === false) {

src/Standards/Squiz/Tests/Arrays/ArrayDeclarationUnitTest.2.inc

@@ -468,3 +468,9 @@ yield [
 $a = [
       'a' =>
      ];
+
+// Ensure absence of NoKeySpecified error for array unpacking
+$x = [
+      'foo' => 'bar',
+    ...$a,
+     ];

src/Standards/Squiz/Tests/Arrays/ArrayDeclarationUnitTest.2.inc.fixed

@@ -502,3 +502,9 @@ yield [
 $a = [
       'a' =>
      ];
+
+// Ensure absence of NoKeySpecified error for array unpacking
+$x = [
+      'foo' => 'bar',
+    ...$a,
+     ];