diff --git a/packages/validator/src/index.ts b/packages/validator/src/index.ts
index c98f4f1..b59cc4b 100644
--- a/packages/validator/src/index.ts
+++ b/packages/validator/src/index.ts
@@ -56,7 +56,7 @@ function _useValidator<Shape>(
   }
 }
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ErrorArgsMap {
       [k: string]: unknown[]
diff --git a/packages/validator/src/types/literal.ts b/packages/validator/src/types/literal.ts
index 113952e..e5e7ad2 100644
--- a/packages/validator/src/types/literal.ts
+++ b/packages/validator/src/types/literal.ts
@@ -1,7 +1,7 @@
 import type { t as tn } from '@typp/core'
 
-import { FALSY } from '../base'
 import type { SwitchBaseType } from '../base.inner'
+import { FALSY } from '../base'
 import { preprocess } from '../utils.inner'
 import { bigintTransform } from './primitive.bigint'
 import { booleanTransform } from './primitive.boolean'
@@ -9,7 +9,7 @@ import { numberTransform } from './primitive.number'
 import { stringTransform } from './primitive.string'
 import { symbolTransform } from './primitive.symbol'
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ValidateExtendsEntries<T> {
       null: [
diff --git a/packages/validator/src/types/primitive.bigint.ts b/packages/validator/src/types/primitive.bigint.ts
index e195ec1..c24e60f 100644
--- a/packages/validator/src/types/primitive.bigint.ts
+++ b/packages/validator/src/types/primitive.bigint.ts
@@ -1,11 +1,11 @@
-import type { IsEqual, IsSubType, IsTrue, IsWhat, Not, OnlySubType, t as tn } from '@typp/core'
+import type { IsEqual, IsWhat, Not, OnlySubType, t as tn } from '@typp/core'
 
-import { FALSY } from '../base'
 import type { LiteralTypeGuard, SwitchBaseType } from '../base.inner'
+import { FALSY } from '../base'
 import { parseBigInt } from '../utils'
 import { preprocess } from '../utils.inner'
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ValidateExtendsEntries<T> {
       bigint: [IsWhat<T, bigint>, bigint | BigInt]
@@ -64,7 +64,7 @@ export const bigintTransform: tn.Validator<bigint>['transform'] = function (inpu
       } else if (input === -Infinity) {
         return 2n ** 1024n * -1n
       } else if (Number.isNaN(input)) {
-        throw new Error('NaN cannot be converted to BigInt')
+        throw new TypeError('NaN cannot be converted to BigInt')
       } else {
         if (input > Number.MAX_SAFE_INTEGER || input < Number.MIN_SAFE_INTEGER) {
           throw new Error('number must greater than or equal to -2^53 and less than or equal to 2^53')
diff --git a/packages/validator/src/types/primitive.boolean.ts b/packages/validator/src/types/primitive.boolean.ts
index 6ceff66..5aeed6c 100644
--- a/packages/validator/src/types/primitive.boolean.ts
+++ b/packages/validator/src/types/primitive.boolean.ts
@@ -4,7 +4,7 @@ import { FALSY } from '../base'
 import type { LiteralTypeGuard, SwitchBaseType } from '../base.inner'
 import { preprocess } from '../utils.inner'
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ValidateExtendsEntries<T> {
       boolean: [
diff --git a/packages/validator/src/types/primitive.number.ts b/packages/validator/src/types/primitive.number.ts
index 7e1e631..23ce9cf 100644
--- a/packages/validator/src/types/primitive.number.ts
+++ b/packages/validator/src/types/primitive.number.ts
@@ -4,7 +4,7 @@ import { FALSY } from '../base'
 import type { LiteralTypeGuard, SwitchBaseType } from '../base.inner'
 import { preprocess } from '../utils.inner'
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ValidateExtendsEntries<T> {
       number: [
diff --git a/packages/validator/src/types/primitive.string.ts b/packages/validator/src/types/primitive.string.ts
index 21e8be9..788f271 100644
--- a/packages/validator/src/types/primitive.string.ts
+++ b/packages/validator/src/types/primitive.string.ts
@@ -3,7 +3,7 @@ import type { IsWhat, OnlySubType, t as tn } from '@typp/core'
 import type { LiteralTypeGuard, SwitchBaseType } from '../base.inner'
 import { preprocess } from '../utils.inner'
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ValidateExtendsEntries<T> {
       string: [
diff --git a/packages/validator/src/types/primitive.symbol.ts b/packages/validator/src/types/primitive.symbol.ts
index 76d0139..c018bbe 100644
--- a/packages/validator/src/types/primitive.symbol.ts
+++ b/packages/validator/src/types/primitive.symbol.ts
@@ -3,7 +3,7 @@ import type { IsWhat, OnlySubType, t as tn } from '@typp/core'
 import type { LiteralTypeGuard } from '../base.inner'
 import { preprocess } from '../utils.inner'
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ValidateExtendsEntries<T> {
       symbol: [
diff --git a/packages/validator/src/types/structural.ts b/packages/validator/src/types/structural.ts
index 20add91..219d498 100644
--- a/packages/validator/src/types/structural.ts
+++ b/packages/validator/src/types/structural.ts
@@ -7,7 +7,7 @@ import { FALSY } from '../base'
 // TODO record
 // TODO class/instanceof
 
-declare module '@typp/core' {
+declare module '@typp/core/base' {
   namespace t {
     export interface ErrorArgsMap {
       /**