Use a strict return type for getNonAssignableReason

Author: kylekatarnls

.codeclimate.yml

@@ -21,7 +21,7 @@ engines:
     - eb746d53b9a8dabef2c1041d8e37158d
     - ef7cef7244578b6906e8785db37f6f48
     # Allow 'is' method
-    - 2ea85a0da934bbb59152f07507296053
+    - ace61d689ad3cd8ba10c4f88c6d33768
     # Allow eval in unit tests
     - a766751f59d0dda7f074443addea8e6f
 ratings:

src/JsPhpize/Nodes/Assignable.php

@@ -4,5 +4,10 @@
 
 interface Assignable
 {
+    /**
+     * Returns false if assignable or the reason it's not as a string.
+     *
+     * @return false|string
+     */
     public function getNonAssignableReason();
 }

src/JsPhpize/Nodes/Assignation.php

@@ -23,7 +23,9 @@ class Assignation extends Value
 
     public function __construct($operator, Assignable $leftHand, Node $rightHand)
     {
-        if ($reason = $leftHand->getNonAssignableReason()) {
+        $reason = $leftHand->getNonAssignableReason();
+
+        if ($reason !== false) {
             throw new Exception($reason, 9);
         }
 

src/JsPhpize/Nodes/Constant.php

@@ -36,5 +36,7 @@ public function getNonAssignableReason()
         if (substr($this->value, 0, 2) === 'M_') {
             return "'M_' prefix is reserved to mathematical constants.";
         }
+
+        return false;
     }
 }

src/JsPhpize/Nodes/Variable.php

@@ -32,5 +32,6 @@ public function setScope(Block $block)
 
     public function getNonAssignableReason()
     {
+        return false;
     }
 }