Be stricter about types

Author: JoviDeCroock

src/language/ast.ts

@@ -530,6 +530,7 @@ export interface SemanticNonNullTypeNode {
 /** Type Reference */
 
 export type TypeNode = NamedTypeNode | ListTypeNode | NonNullTypeNode;
+export type SchemaOutputTypeNode = NamedTypeNode | ListTypeNode | NonNullTypeNode | SemanticNonNullTypeNode;
 
 export interface NamedTypeNode {
   readonly kind: Kind.NAMED_TYPE;
@@ -540,7 +541,13 @@ export interface NamedTypeNode {
 export interface ListTypeNode {
   readonly kind: Kind.LIST_TYPE;
   readonly loc?: Location;
-  readonly type: TypeNode | SemanticNonNullTypeNode;
+  readonly type: TypeNode;
+}
+
+export interface SchemaListTypeNode {
+  readonly kind: Kind.LIST_TYPE;
+  readonly loc?: Location;
+  readonly type: SchemaOutputTypeNode;
 }
 
 export interface NonNullTypeNode {

src/utilities/extendSchema.ts

@@ -24,9 +24,8 @@ import type {
   ScalarTypeExtensionNode,
   SchemaDefinitionNode,
   SchemaExtensionNode,
-  SemanticNonNullTypeNode,
+  SchemaOutputTypeNode,
   TypeDefinitionNode,
-  TypeNode,
   UnionTypeDefinitionNode,
   UnionTypeExtensionNode,
 } from '../language/ast';
@@ -433,7 +432,7 @@ export function extendSchemaImpl(
   }
 
   function getWrappedType(
-    node: TypeNode | SemanticNonNullTypeNode,
+    node: SchemaOutputTypeNode,
   ): GraphQLType {
     if (node.kind === Kind.LIST_TYPE) {
       return new GraphQLList(getWrappedType(node.type));