fix: limit styled button type

.storybook/src/v4.0.0.mdx

@@ -121,6 +121,25 @@ After
 <Button component={NextLink} href="...">Link</Button>
 ```
 
+### ButtonのGeneric propsについて
+
+[Styled Componentの制限](https://github.com/styled-components/styled-components/issues/1803)により`styled(Button)`で拡張する場合propsがうまく推論されない場合があります。
+Charcoal v4.1.0から過剰なpropsを検出する処理を追加したが、`component` propと合わせて使う時の型を配慮する必要があります。
+
+サンプル
+
+```tsx
+// allow component
+const StyledButton = styled(Button)`` as typeof Button
+<StyledButton component={Link} to="#" />
+
+// preserve component type
+const StyledButtonA = styled(Button<'a'>)``
+<StyledButtonA component="a" href="#" />
+```
+
+その他のケースは [styledButtonTypeTest.d.tsx](https://github.com/pixiv/charcoal/blob/main/packages/react/src/components/Button/styledButtonTypeTest.d.tsx) を参考してください。
+
 ## Checkbox
 
 - `Checkbox`の`input`要素を`children`がない場合に label で囲わないようにしました。

packages/react/src/components/Button/index.tsx

@@ -46,5 +46,11 @@ const Button = forwardRef(function Button<T extends React.ElementType>(
       ref={ref}
     />
   )
-}) as <T extends React.ElementType = 'button'>(p: ButtonProps<T>) => JSX.Element
+}) as <T extends React.ElementType = 'button'>(
+  p: 'button' extends T
+    ? ButtonProps<'button'>
+    : ButtonProps<T> & {
+        component: T // required
+      }
+) => JSX.Element
 export default Button

packages/react/src/components/Button/styledButtonTypeTest.d.tsx

@@ -0,0 +1,81 @@
+// This file is for type testing only
+
+// only use the type
+import type { default as ButtonType } from './index'
+import type styledType from 'styled-components'
+
+declare const Button: typeof ButtonType
+declare const styled: typeof styledType
+
+const Custom = ({ custom }: { custom: string }) => <>{custom}</>
+const CustomGeneric = <C extends string>({ custom }: { custom: C }) => (
+  <>{custom}</>
+)
+
+const StyledButton = styled(Button)``
+const StyledButtonAsButton = styled(Button<'button'>)``
+const StyledButtonA = styled(Button<'a'>)``
+const StyledButtonCustom = styled(Button<typeof Custom>)``
+const StyledButtonCustomAsButton = styled(
+  Button<typeof Custom>
+)`` as typeof Button
+const StyledButtonCustomGeneric = styled(Button<typeof CustomGeneric>)``
+const StyledButtonCustomGenericFoo = styled(
+  Button<typeof CustomGeneric<'foo'>>
+)``
+
+// for type test only
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+function Tests() {
+  return (
+    <>
+      {/* OK */}
+
+      <StyledButton />
+      <StyledButton type="button" disabled />
+      <StyledButtonAsButton type="button" disabled />
+      <StyledButtonA component="a" href="#" />
+      <StyledButtonCustom component={Custom} custom="" />
+      <StyledButtonCustomAsButton<'a'> component="a" href="#" />
+      <StyledButtonCustomAsButton<typeof CustomGeneric<'bar'>>
+        component={CustomGeneric}
+        custom="bar"
+      />
+      <StyledButtonCustomAsButton component="a" href="#" />
+      <StyledButtonCustomGeneric component={CustomGeneric} custom="" />
+      <StyledButtonCustomGenericFoo component={CustomGeneric} custom="foo" />
+      <StyledButtonCustomGenericFoo
+        component={CustomGeneric<'foo'>}
+        custom="foo"
+      />
+
+      {/* NG */}
+
+      {/* @ts-expect-error Property 'href' does not exist on type  */}
+      <StyledButton href="" />
+      {/* @ts-expect-error Property 'href' does not exist on type  */}
+      <StyledButtonAsButton href="" />
+      {/* @ts-expect-error Property 'component' is missing */}
+      <StyledButtonA href="#" />
+      {/* @ts-expect-error Property 'disabled' does not exist on type  */}
+      <StyledButtonA disabled />
+      {/* @ts-expect-error Type '"button"' is not assignable to type '"a"'  */}
+      <StyledButtonA component="button" href="" />
+      {/* @ts-expect-error Property 'component' is missing */}
+      <StyledButtonCustom custom="" />
+      {/* @ts-expect-error Type 'string' is not assignable  */}
+      <StyledButtonCustom component="a" custom="" />
+      {/* @ts-expect-error Property 'custom' does not exist on type  */}
+      <StyledButtonCustomAsButton custom="" />
+      {/* @ts-expect-error Type 'href' is not assignable  */}
+      <StyledButtonCustomAsButton<'button'> href="#" />
+      <StyledButtonCustomGenericFoo
+        /* @ts-expect-error Type '"foo"' is not assignable to type '"bar"' */
+        component={CustomGeneric<'bar'>}
+        custom="foo"
+      />
+      {/* @ts-expect-error '""' is not assignable to type '"foo"' */}
+      <StyledButtonCustomGenericFoo custom="" />
+    </>
+  )
+}