Generate warning for use of else and elseif

Chadicus/Docs/ControlStructures/ElseIfAndElseDeclarationStandard.xml

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+<documentation title="ElseIf and Else Declarations">
+    <standard>
+    <![CDATA[
+    An if expression with an else branch is never necessary.  You can rewrite the conditions in a way that the else is not necessary and the code becomes simpler to read.
+    ]]>
+    </standard>
+    <code_comparison>
+        <code title="Valid: Method returns early to avoid use of else.">
+        <![CDATA[
+public function bar($flag)
+{
+    if ($flag) {
+        // perform action in true case
+        return;
+    } 
+
+    // perform action in false case
+}
+        ]]>
+        </code>
+        <code title="Invalid: Else statement used.">
+        <![CDATA[
+public function bar($flag)
+{
+    if ($flag) {
+        // perform action in true case
+    <em>} else {</em>
+        // perform action in false case
+    }
+}
+        ]]>
+        </code>
+    </code_comparison>
+</documentation>

Chadicus/Sniffs/ControlStructures/ElseIfAndElseDeclarationSniff.php

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+<?php
+/**
+ * Generates a warning if else or elseif control structures are used.
+ */
+final class Chadicus_Sniffs_ControlStructures_ElseIfAndElseDeclarationSniff implements PHP_CodeSniffer_Sniff
+{
+
+    /**
+     * Returns an array of tokens this test wants to listen for.
+     *
+     * @return array
+     */
+    public function register()
+    {
+        return [T_ELSEIF, T_ELSE];
+    }
+
+    /**
+     * Processes this test, when one of its tokens is encountered.
+     *
+     * @param PHP_CodeSniffer_File $phpcsFile The file being scanned.
+     * @param integer              $stackPtr  The position of the current token in the stack passed in $tokens.
+     *
+     * @return void
+     */
+    public function process(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
+    {
+        $error = 'Use of ELSE and ELSEIF is discouraged. An if expression with an else branch is never necessary. You '
+               . 'can rewrite the conditions in a way that the else is not necessary and the code becomes simpler to '
+               . 'read.';
+        $phpcsFile->addWarning($error, $stackPtr, 'Discouraged');
+    }
+}