diff --git a/UPGRADE.md b/UPGRADE.md
index 0a7e12639..325b34a30 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -21,7 +21,7 @@ $e = new Error(
     'msg',
     null,
     null,
-    null,
+    [],
     null,
     null,
     ['foo' => 'bar']
diff --git a/src/Error/Error.php b/src/Error/Error.php
index 35bedb6da..ecf383ebf 100644
--- a/src/Error/Error.php
+++ b/src/Error/Error.php
@@ -66,7 +66,7 @@ class Error extends Exception implements JsonSerializable, ClientAware
      */
     private $source;
 
-    /** @var int[]|null */
+    /** @var int[] */
     private $positions;
 
     /** @var bool */
@@ -81,7 +81,7 @@ class Error extends Exception implements JsonSerializable, ClientAware
     /**
      * @param string                       $message
      * @param Node|Node[]|Traversable|null $nodes
-     * @param mixed[]|null                 $positions
+     * @param mixed[]                      $positions
      * @param mixed[]|null                 $path
      * @param Throwable                    $previous
      * @param mixed[]                      $extensions
@@ -90,7 +90,7 @@ public function __construct(
         $message,
         $nodes = null,
         ?Source $source = null,
-        $positions = null,
+        array $positions = [],
         $path = null,
         $previous = null,
         array $extensions = []
@@ -100,7 +100,7 @@ public function __construct(
         // Compute list of blame nodes.
         if ($nodes instanceof Traversable) {
             $nodes = iterator_to_array($nodes);
-        } elseif ($nodes && ! is_array($nodes)) {
+        } elseif ($nodes !== null && ! is_array($nodes)) {
             $nodes = [$nodes];
         }
 
@@ -109,7 +109,7 @@ public function __construct(
         $this->positions  = $positions;
         $this->path       = $path;
         $this->extensions = count($extensions) > 0 ? $extensions : (
-        $previous && $previous instanceof self
+        $previous instanceof self
             ? $previous->extensions
             : []
         );
@@ -118,7 +118,7 @@ public function __construct(
             $this->isClientSafe = $previous->isClientSafe();
             $cat                = $previous->getCategory();
             $this->category     = $cat === '' || $cat === null  ? self::CATEGORY_INTERNAL: $cat;
-        } elseif ($previous) {
+        } elseif ($previous !== null) {
             $this->isClientSafe = false;
             $this->category     = self::CATEGORY_INTERNAL;
         } else {
@@ -141,7 +141,7 @@ public function __construct(
     public static function createLocatedError($error, $nodes = null, $path = null)
     {
         if ($error instanceof self) {
-            if ($error->path && $error->nodes) {
+            if ($error->path !== null && $error->nodes !== null && count($error->nodes) !== 0) {
                 return $error;
             }
 
@@ -149,8 +149,10 @@ public static function createLocatedError($error, $nodes = null, $path = null)
             $path  = $path ?? $error->path;
         }
 
-        $source     = $positions = $originalError = null;
-        $extensions = [];
+        $source        = null;
+        $originalError = null;
+        $positions     = [];
+        $extensions    = [];
 
         if ($error instanceof self) {
             $message       = $error->getMessage();
@@ -218,9 +220,9 @@ public function getSource()
     /**
      * @return int[]
      */
-    public function getPositions()
+    public function getPositions() : array
     {
-        if ($this->positions === null && ! empty($this->nodes)) {
+        if (count($this->positions) === 0 && ! empty($this->nodes)) {
             $positions = array_map(
                 static function ($node) : ?int {
                     return isset($node->loc) ? $node->loc->start : null;
@@ -263,14 +265,14 @@ public function getLocations()
             $source    = $this->getSource();
             $nodes     = $this->nodes;
 
-            if ($positions && $source) {
+            if ($source !== null && count($positions) !== 0) {
                 $this->locations = array_map(
                     static function ($pos) use ($source) : SourceLocation {
                         return $source->getLocation($pos);
                     },
                     $positions
                 );
-            } elseif ($nodes) {
+            } elseif ($nodes !== null && count($nodes) !== 0) {
                 $locations       = array_filter(
                     array_map(
                         static function ($node) : ?SourceLocation {
diff --git a/src/Utils/ASTDefinitionBuilder.php b/src/Utils/ASTDefinitionBuilder.php
index 05a3b5ad5..226c6332b 100644
--- a/src/Utils/ASTDefinitionBuilder.php
+++ b/src/Utils/ASTDefinitionBuilder.php
@@ -215,7 +215,7 @@ private function internalBuildType($typeName, $typeNode = null)
                             sprintf('when building %s type: %s', $typeName, $e->getMessage()),
                             null,
                             null,
-                            null,
+                            [],
                             null,
                             $e
                         );
diff --git a/src/Utils/Value.php b/src/Utils/Value.php
index 2920883a6..e1e42e98e 100644
--- a/src/Utils/Value.php
+++ b/src/Utils/Value.php
@@ -249,7 +249,7 @@ private static function coercionError(
             ($subMessage ? '; ' . $subMessage : '.'),
             $blameNode,
             null,
-            null,
+            [],
             null,
             $originalError
         );
diff --git a/tests/Error/ErrorTest.php b/tests/Error/ErrorTest.php
index 4614177d5..9486ce90b 100644
--- a/tests/Error/ErrorTest.php
+++ b/tests/Error/ErrorTest.php
@@ -20,7 +20,7 @@ class ErrorTest extends TestCase
     public function testUsesTheStackOfAnOriginalError() : void
     {
         $prev = new Exception('Original');
-        $err  = new Error('msg', null, null, null, null, $prev);
+        $err  = new Error('msg', null, null, [], null, $prev);
 
         self::assertSame($err->getPrevious(), $prev);
     }
@@ -134,7 +134,7 @@ public function testSerializesToIncludePath() : void
             'msg',
             null,
             null,
-            null,
+            [],
             ['path', 3, 'to', 'field']
         );
 
@@ -151,7 +151,7 @@ public function testDefaultErrorFormatterIncludesExtensionFields() : void
             'msg',
             null,
             null,
-            null,
+            [],
             null,
             null,
             ['foo' => 'bar']
diff --git a/tests/Executor/ExecutorTest.php b/tests/Executor/ExecutorTest.php
index 33ae342b7..7ad87a607 100644
--- a/tests/Executor/ExecutorTest.php
+++ b/tests/Executor/ExecutorTest.php
@@ -461,7 +461,7 @@ public function testNullsOutErrorSubtrees() : void
                         'Error getting asyncReturnErrorWithExtensions',
                         null,
                         null,
-                        null,
+                        [],
                         null,
                         null,
                         ['foo' => 'bar']