[styles] Fix styled types not including properties

Author: merceyz

packages/material-ui-styles/src/styled/styled.d.ts

@@ -6,6 +6,12 @@ import {
 } from '@material-ui/styles/withStyles';
 import * as React from 'react';
 
+/**
+ * If props is any, returns empty object, otherwise T
+ * @internal
+ */
+export type GetProps<T> = 0 extends 1 & T ? {} : T;
+
 /**
  * @internal
  */
@@ -19,7 +25,7 @@ export type ComponentCreator<Component extends React.ElementType> = <Theme, Prop
     JSX.LibraryManagedAttributes<Component, React.ComponentProps<Component>>,
     'classes' | 'className'
   > &
-    StyledComponentProps<'root'> & { className?: string }
+    StyledComponentProps<'root'> & { className?: string } & GetProps<Props>
 >;
 
 export interface StyledProps {

packages/material-ui-styles/test/index.spec.tsx

@@ -155,6 +155,9 @@ import styled, { StyledProps } from '@material-ui/styles/styled';
   interface MyTheme {
     fontFamily: string;
   }
+  const MyThemeInstance: MyTheme = {
+    fontFamily: 'monospace',
+  };
   // tslint:disable-next-line: no-empty-interface
   interface MyComponentProps extends StyledProps {
     defaulted: string;
@@ -176,7 +179,7 @@ import styled, { StyledProps } from '@material-ui/styles/styled';
   const renderedMyComponent = (
     <>
       <MyComponent className="test" />
-      <StyledMyComponent />
+      <StyledMyComponent theme={MyThemeInstance} />
     </>
   );
 }