Add regression tests

src/services/codefixes/importFixes.ts

@@ -798,6 +798,7 @@ namespace ts.codefix {
                         }
                     }
                     else if (isExportSpecifier(declaration)) {
+                        Debug.assert(declaration.name.escapedText === InternalSymbolName.Default);
                         if (declaration.propertyName) {
                             return declaration.propertyName.escapedText;
                         }

tests/cases/fourslash/importNameCodeFixDefaultExport2.ts

@@ -0,0 +1,21 @@
+/// <reference path="fourslash.ts" />
+
+// @allowJs: true
+// @checkJs: true
+
+// @Filename: /lib.js
+////class Base { }
+////export default Base;
+
+// @Filename: /test.js
+////[|class Derived extends Base { }|]
+
+goTo.file("/test.js");
+verify.importFixAtPosition([
+`// @ts-ignore
+class Derived extends Base { }`,
+`// @ts-nocheck
+class Derived extends Base { }`,
+`import Base from "./lib";
+
+class Derived extends Base { }`,]);

tests/cases/fourslash/importNameCodeFixDefaultExport3.ts

@@ -0,0 +1,21 @@
+/// <reference path="fourslash.ts" />
+
+// @allowJs: true
+// @checkJs: true
+
+// @Filename: /lib.js
+////class Base { }
+////export { Base as default };
+
+// @Filename: /test.js
+////[|class Derived extends Base { }|]
+
+goTo.file("/test.js");
+verify.importFixAtPosition([
+`// @ts-ignore
+class Derived extends Base { }`,
+`// @ts-nocheck
+class Derived extends Base { }`,
+`import Base from "./lib";
+
+class Derived extends Base { }`,]);