fix(eslint-plugin): [no-type-alias] consider type imports as alias types (typescript-eslint#3433)

Josh Goldberg · web-flow · commit d4f077473afb · 2021-05-28T16:51:01.000-07:00
diff --git a/packages/eslint-plugin/src/rules/no-type-alias.ts b/packages/eslint-plugin/src/rules/no-type-alias.ts
@@ -122,6 +122,7 @@ export default util.createRule<Options, MessageIds>({
     ];
     const aliasTypes = new Set([
       AST_NODE_TYPES.TSArrayType,
+      AST_NODE_TYPES.TSImportType,
       AST_NODE_TYPES.TSTypeReference,
       AST_NODE_TYPES.TSLiteralType,
       AST_NODE_TYPES.TSTypeQuery,
diff --git a/packages/eslint-plugin/tests/rules/no-type-alias.test.ts b/packages/eslint-plugin/tests/rules/no-type-alias.test.ts
@@ -394,6 +394,10 @@ export type ClassValue =
       code: 'type Foo = typeof bar;',
       options: [{ allowAliases: 'always' }],
     },
+    {
+      code: "type Foo = typeof import('foo');",
+      options: [{ allowAliases: 'always' }],
+    },
     {
       code: `
 const WithAKey = { AKey: true };
@@ -405,6 +409,10 @@ type KeyNames = keyof typeof SCALARS;
       code: 'type Foo = typeof bar | typeof baz;',
       options: [{ allowAliases: 'in-unions' }],
     },
+    {
+      code: "type Foo = typeof bar | typeof import('foo');",
+      options: [{ allowAliases: 'in-unions' }],
+    },
     {
       code: 'type Foo = keyof [string];',
       options: [{ allowTupleTypes: 'always' }],
@@ -505,6 +513,20 @@ type KeyNames = keyof typeof SCALARS;
         },
       ],
     },
+    {
+      code: "type Foo = typeof import('foo');",
+      options: [{ allowAliases: 'never' }],
+      errors: [
+        {
+          messageId: 'noTypeAlias',
+          data: {
+            alias: 'aliases',
+          },
+          line: 1,
+          column: 12,
+        },
+      ],
+    },
     {
       code: "type Foo = 'a' | 'b';",
       errors: [
@@ -528,6 +550,29 @@ type KeyNames = keyof typeof SCALARS;
         },
       ],
     },
+    {
+      code: "type Foo = 'a' | typeof import('foo');",
+      errors: [
+        {
+          messageId: 'noCompositionAlias',
+          data: {
+            typeName: 'Aliases',
+            compositionType: 'union',
+          },
+          line: 1,
+          column: 12,
+        },
+        {
+          messageId: 'noCompositionAlias',
+          data: {
+            typeName: 'Aliases',
+            compositionType: 'union',
+          },
+          line: 1,
+          column: 18,
+        },
+      ],
+    },
     {
       code: "type Foo = 'a' | 'b';",
       options: [{ allowLiterals: 'in-unions' }],
