Generic/RequireStrictTypes: add warning for when value is 0

Strict types is disabled when the value for the `strict_types` directive is `0`.

As this sniff is supposed to be about enforcing the use of `strict_types`, `strict_types` declarations which turn the feature off should be flagged as well.

Implemented with a separate error code to allow for selectively turning this warning off.

Includes dedicated tests.

src/Standards/Generic/Sniffs/PHP/RequireStrictTypesSniff.php

@@ -77,6 +77,25 @@ public function process(File $phpcsFile, $stackPtr)
         if ($found === false) {
             $error = 'Missing required strict_types declaration';
             $phpcsFile->addError($error, $stackPtr, 'MissingDeclaration');
+
+            return $phpcsFile->numTokens;
+        }
+
+        // Strict types declaration found, make sure strict types is enabled.
+        $skip     = Tokens::$emptyTokens;
+        $skip[]   = T_EQUAL;
+        $valuePtr = $phpcsFile->findNext($skip, ($next + 1), null, true);
+
+        if ($valuePtr !== false
+            && $tokens[$valuePtr]['code'] === T_LNUMBER
+            && $tokens[$valuePtr]['content'] === '0'
+        ) {
+            $error = 'Required strict_types declaration found, but strict types is disabled. Set the value to 1 to enable';
+            $fix   = $phpcsFile->addFixableWarning($error, $valuePtr, 'Disabled');
+
+            if ($fix === true) {
+                $phpcsFile->fixer->replaceToken($valuePtr, '1');
+            }
         }
 
         // Skip the rest of the file so we don't pick up additional

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.11.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=0);
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.11.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.12.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare(  strict_types  =   /*comment*/   0   );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.12.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare(  strict_types  =   /*comment*/   1   );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.13.inc

@@ -0,0 +1,3 @@
+<?php
+// Safeguard sniff handles parse error/live coding correctly.
+declare(strict_types=

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.14.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare( strict_types = 0, encoding='utf-8' );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.14.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare( strict_types = 1, encoding='utf-8' );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.15.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare(encoding='utf-8', strict_types=0);
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.15.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare(encoding='utf-8', strict_types=1);
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.php

@@ -44,14 +44,22 @@ public function getErrorList($testFile='')
     /**
      * Returns the lines where warnings should occur.
      *
-     * The key of the array should represent the line number and the value
-     * should represent the number of warnings that should occur on that line.
+     * @param string $testFile The name of the file being tested.
      *
      * @return array<int, int>
      */
-    public function getWarningList()
+    public function getWarningList($testFile='')
     {
-        return [];
+        switch ($testFile) {
+        case 'RequireStrictTypesUnitTest.11.inc':
+        case 'RequireStrictTypesUnitTest.12.inc':
+        case 'RequireStrictTypesUnitTest.14.inc':
+        case 'RequireStrictTypesUnitTest.15.inc':
+            return [3 => 1];
+
+        default:
+            return [];
+        }
 
     }//end getWarningList()