diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 09f3df772..e77366fc6 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -815,11 +815,6 @@ parameters:
 			count: 1
 			path: src/Utils/ASTDefinitionBuilder.php
 
-		-
-			message: "#^Only booleans are allowed in an if condition, GraphQL\\\\Language\\\\AST\\\\BooleanValueNode\\|GraphQL\\\\Language\\\\AST\\\\EnumValueNode\\|GraphQL\\\\Language\\\\AST\\\\FloatValueNode\\|GraphQL\\\\Language\\\\AST\\\\IntValueNode\\|GraphQL\\\\Language\\\\AST\\\\ListValueNode\\|GraphQL\\\\Language\\\\AST\\\\NullValueNode\\|GraphQL\\\\Language\\\\AST\\\\ObjectValueNode\\|GraphQL\\\\Language\\\\AST\\\\StringValueNode\\|GraphQL\\\\Language\\\\AST\\\\VariableNode given\\.$#"
-			count: 1
-			path: src/Utils/ASTDefinitionBuilder.php
-
 		-
 			message: "#^Anonymous function should have native return typehint \"bool\"\\.$#"
 			count: 2
@@ -1496,22 +1491,22 @@ parameters:
 			path: src/Validator/Rules/ValuesOfCorrectType.php
 
 		-
-			message: "#^Only booleans are allowed in \\|\\|, GraphQL\\\\Type\\\\Definition\\\\EnumType\\|GraphQL\\\\Type\\\\Definition\\\\InputObjectType\\|GraphQL\\\\Type\\\\Definition\\\\ListOfType\\|GraphQL\\\\Type\\\\Definition\\\\NonNull\\|GraphQL\\\\Type\\\\Definition\\\\ScalarType given on the left side\\.$#"
+			message: "#^Anonymous function should have native return typehint \"string\"\\.$#"
 			count: 1
 			path: src/Validator/Rules/ValuesOfCorrectType.php
 
 		-
-			message: "#^Only booleans are allowed in a negated boolean, GraphQL\\\\Type\\\\Definition\\\\EnumValueDefinition\\|null given\\.$#"
+			message: "#^Only booleans are allowed in \\|\\|, GraphQL\\\\Type\\\\Definition\\\\EnumType\\|GraphQL\\\\Type\\\\Definition\\\\InputObjectType\\|GraphQL\\\\Type\\\\Definition\\\\ListOfType\\|GraphQL\\\\Type\\\\Definition\\\\NonNull\\|GraphQL\\\\Type\\\\Definition\\\\ScalarType given on the left side\\.$#"
 			count: 1
 			path: src/Validator/Rules/ValuesOfCorrectType.php
 
 		-
-			message: "#^Only booleans are allowed in a negated boolean, GraphQL\\\\Type\\\\Definition\\\\EnumType\\|GraphQL\\\\Type\\\\Definition\\\\InputObjectType\\|GraphQL\\\\Type\\\\Definition\\\\ListOfType\\|GraphQL\\\\Type\\\\Definition\\\\NonNull\\|GraphQL\\\\Type\\\\Definition\\\\ScalarType given\\.$#"
+			message: "#^Only booleans are allowed in a negated boolean, GraphQL\\\\Type\\\\Definition\\\\EnumValueDefinition\\|null given\\.$#"
 			count: 1
 			path: src/Validator/Rules/ValuesOfCorrectType.php
 
 		-
-			message: "#^Anonymous function should have native return typehint \"string\"\\.$#"
+			message: "#^Only booleans are allowed in a negated boolean, GraphQL\\\\Type\\\\Definition\\\\EnumType\\|GraphQL\\\\Type\\\\Definition\\\\InputObjectType\\|GraphQL\\\\Type\\\\Definition\\\\ListOfType\\|GraphQL\\\\Type\\\\Definition\\\\NonNull\\|GraphQL\\\\Type\\\\Definition\\\\ScalarType given\\.$#"
 			count: 1
 			path: src/Validator/Rules/ValuesOfCorrectType.php
 
diff --git a/src/Language/AST/InputValueDefinitionNode.php b/src/Language/AST/InputValueDefinitionNode.php
index 647de0923..34ec2766a 100644
--- a/src/Language/AST/InputValueDefinitionNode.php
+++ b/src/Language/AST/InputValueDefinitionNode.php
@@ -15,7 +15,7 @@ class InputValueDefinitionNode extends Node
     /** @var NamedTypeNode|ListTypeNode|NonNullTypeNode */
     public $type;
 
-    /** @var VariableNode|NullValueNode|IntValueNode|FloatValueNode|StringValueNode|BooleanValueNode|EnumValueNode|ListValueNode|ObjectValueNode */
+    /** @var VariableNode|NullValueNode|IntValueNode|FloatValueNode|StringValueNode|BooleanValueNode|EnumValueNode|ListValueNode|ObjectValueNode|null */
     public $defaultValue;
 
     /** @var DirectiveNode[] */
diff --git a/src/Utils/ASTDefinitionBuilder.php b/src/Utils/ASTDefinitionBuilder.php
index 851f1f430..d9902b1f2 100644
--- a/src/Utils/ASTDefinitionBuilder.php
+++ b/src/Utils/ASTDefinitionBuilder.php
@@ -472,7 +472,7 @@ public function buildInputField(InputValueDefinitionNode $value) : array
             'astNode' => $value,
         ];
 
-        if ($value->defaultValue) {
+        if ($value->defaultValue !== null) {
             $config['defaultValue'] = $value->defaultValue;
         }