Fix broken object and lazy types

src/lib/_helpers.ts

@@ -4,7 +4,7 @@
  * Returns all the keys from T where `undefined` can be assigned to.
  */
 type OptionalKeys<T> = {
-  [K in keyof T]-?: K extends any ? (undefined extends T[K] ? K : never) : never;
+  [K in keyof T]-?: undefined extends T[K] ? K : never;
 }[keyof T];
 
 type RequiredKeys<T> = Exclude<keyof T, OptionalKeys<T>>;
@@ -25,7 +25,7 @@ type RequiredKeys<T> = Exclude<keyof T, OptionalKeys<T>>;
  *
  *   {
  *     name: string;
- *     age?: number | null;
+ *     age?: number | null | undefined;
  *        ^
  *        Note the question mark
  *   }

src/lib/objects.ts

@@ -5,12 +5,11 @@ import { define } from '../Decoder';
 import { subtract, isPojo } from '../_utils';
 import type { Annotation } from '../annotate';
 import type { Decoder, DecodeResult } from '../Decoder';
+import type { AllowImplicit } from './_helpers';
 
-// TODO: Restore AllowImplicit here somehow
-// import type { AllowImplicit } from './_helpers';
-type ObjectDecoderType<T> = {
+type ObjectDecoderType<T> = AllowImplicit<{
   [K in keyof T]: T[K] extends Decoder<infer V> ? V : never;
-};
+}>;
 
 /**
  * Accepts any "plain old JavaScript object", but doesn't validate its keys or
@@ -170,7 +169,9 @@ export function inexact<O extends Record<string, Decoder<any>>>(
       } & Record<string, unknown>;
       allkeys.forEach((k) => {
         if (safekeys.has(k)) {
-          const value = safepart[k];
+          const value =
+            // @ts-expect-error - look into this later
+            safepart[k];
           if (value !== undefined) {
             // @ts-expect-error - look into this later
             rv[k] = value;