fix(eslint-plugin): handle error classes using generics

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

@@ -29,7 +29,11 @@ export default util.createRule({
 
     function isErrorLike(type: ts.Type): boolean {
       const symbol = type.getSymbol();
-      if (symbol?.getName() === 'Error') {
+      if (!symbol) {
+        return false;
+      }
+
+      if (symbol.getName() === 'Error') {
         const declarations = symbol.getDeclarations() ?? [];
         for (const declaration of declarations) {
           const sourceFile = declaration.getSourceFile();
@@ -39,7 +43,7 @@ export default util.createRule({
         }
       }
 
-      const baseTypes = type.getBaseTypes() ?? [];
+      const baseTypes = checker.getBaseTypes(type as ts.InterfaceType);
       for (const baseType of baseTypes) {
         if (isErrorLike(baseType)) {
           return true;

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

@@ -14,8 +14,8 @@ const ruleTester = new RuleTester({
 ruleTester.run('no-throw-literal', rule, {
   valid: [
     'throw new Error();',
-    "throw new Error('error');",
-    "throw Error('error');",
+    'throw new Error("error");',
+    'throw Error("error");',
     `
 const e = new Error();
 throw e;
@@ -65,16 +65,28 @@ throw new CustomError();
     `,
     'throw foo = new Error();',
     'throw 1, 2, new Error();',
-    "throw 'literal' && new Error();",
-    "throw new Error() || 'literal'",
-    "throw foo ? new Error() : 'literal';",
-    "throw foo ? 'literal' : new Error();",
+    'throw "literal" && new Error();',
+    'throw new Error() || "literal"',
+    'throw foo ? new Error() : "literal";',
+    'throw foo ? "literal" : new Error();',
     'function* foo() { let index = 0; throw yield index++; }',
     'async function foo() { throw await bar; }',
     `
 import { Error } from './missing';
 throw Error;
     `,
+    `
+class CustomError<T, C> extends Error {}
+throw new CustomError<string, string>();
+    `,
+    `
+class CustomError<T = {}> extends Error {}
+throw new CustomError();
+    `,
+    `
+class CustomError<T extends object> extends Error {}
+throw new CustomError();
+    `,
   ],
   invalid: [
     {
@@ -86,15 +98,15 @@ throw Error;
       ],
     },
     {
-      code: "throw new String('');",
+      code: 'throw new String("");',
       errors: [
         {
           messageId: 'object',
         },
       ],
     },
     {
-      code: "throw 'error';",
+      code: 'throw "error";',
       errors: [
         {
           messageId: 'object',
@@ -134,7 +146,7 @@ throw Error;
       ],
     },
     {
-      code: "throw 'a' + 'b';",
+      code: 'throw "a" + "b";',
       errors: [
         {
           messageId: 'object',
@@ -153,7 +165,7 @@ throw a + 'b';
       ],
     },
     {
-      code: "throw foo = 'error';",
+      code: 'throw foo = "error";',
       errors: [
         {
           messageId: 'object',
@@ -169,15 +181,15 @@ throw a + 'b';
       ],
     },
     {
-      code: "throw 'literal' && 'not an Error';",
+      code: 'throw "literal" && "not an Error";',
       errors: [
         {
           messageId: 'object',
         },
       ],
     },
     {
-      code: "throw foo ? 'not an Error' : 'literal';",
+      code: 'throw foo ? "not an Error" : "literal";',
       errors: [
         {
           messageId: 'object',
@@ -288,5 +300,18 @@ throw new Error();
         },
       ],
     },
+    {
+      code: `
+class CustomError<T extends object> extends Foo {}
+throw new CustomError();
+      `,
+      errors: [
+        {
+          messageId: 'object',
+          line: 3,
+          column: 7,
+        },
+      ],
+    },
   ],
 });