fix(eslint-plugin): [no-throw-literal] handle intersection and union types

packages/eslint-plugin/src/rules/no-throw-literal.ts

@@ -28,6 +28,13 @@ export default util.createRule({
     const checker = program.getTypeChecker();
 
     function isErrorLike(type: ts.Type): boolean {
+      if (type.isIntersection()) {
+        return type.types.some(isErrorLike);
+      }
+      if (type.isUnion()) {
+        return type.types.every(isErrorLike);
+      }
+
       const symbol = type.getSymbol();
       if (!symbol) {
         return false;

packages/eslint-plugin/tests/rules/no-throw-literal.test.ts

@@ -96,6 +96,19 @@ throw new CustomError();
 class CustomError<T extends object> extends Error {}
 throw new CustomError();
     `,
+    `
+function foo() {
+  throw Object.assign(new Error('message'), { foo: 'bar' });
+}
+    `,
+    {
+      code: `
+const foo: Error | SyntaxError = bar();
+function bar() {
+  throw foo;
+}
+      `,
+    },
   ],
   invalid: [
     {
@@ -352,5 +365,30 @@ function foo<T>(fn: () => Promise<T>) {
         },
       ],
     },
+    {
+      code: `
+function foo() {
+  throw Object.assign({ foo: 'foo' }, { bar: 'bar' });
+}
+      `,
+      errors: [
+        {
+          messageId: 'object',
+        },
+      ],
+    },
+    {
+      code: `
+const foo: Error | { bar: string } = bar();
+function bar() {
+  throw foo;
+}
+      `,
+      errors: [
+        {
+          messageId: 'object',
+        },
+      ],
+    },
   ],
 });