Shadowed import bindings require cross-file knowledge even with isolatedModules

[nicolo-ribaudo]

🔎 Search Terms

isolatedModules import duplicate

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/dev/bug-workbench/?ts=5.4.4#code/PTAEAEGcAsHsHcCiBbAlgFwFAggQwDby4CekAyugE6oDG6oVArgKbZjiqSz67rMAmAWVj9G+ZpAaUWbCADdmlAEa9UyYaPFliAO3S4AHlJlt2AM1TiduZMwBcoM7FgA6dJEzMDAB1iV66MTezKAAYs6gALygAN4AvgDcnj5+9DSwOpD0AEK4lFGxiZimEBZWNvagqDr8Xm4ear7+sWHOADSguflxjpSwyKAA5C7ATrCDxWaMOnSoGa2wABQAlIWYUzPoczqdeStrmEA

💻 Code

/// @filename: index.ts
import { Foo, Bar } from './foo'

function Foo() {}
function Bar() {}

/// @filename: foo.ts
export type Foo = {};
export const Bar = {};

🙁 Actual behavior

TS complains about the redeclaration of Bar but not about the redeclaration of Foo

🙂 Expected behavior

Given that inside index.ts Foo and Bar are used exactly the same way, they both should be an error (or both allowed, but it's less desirable).

Additional information about the issue

This was originally reported to Babel at babel/babel#16423, but we cannot match the TS semantics because they require cross-file knowledge (and isolatedModules is supposed to prevent that).

[andrewbranch]

You forgot colons in your bug workbench compiler options. The behavior you’re looking for already exists: https://www.typescriptlang.org/dev/bug-workbench/?isolatedModules=true&verbatimModuleSyntax=true&ts=5.4.4#code/PTAEAEGcAsHsHcCiBbAlgFwFAggQwDby4CekAyugE6oDG6AXKFQK4Cm2Y4qks+u6rACYBZWIOb5WkRi3Y5wAN1aUARv1TJR4yWWIA7dLgAeMym0wdOAM1SS9uZK0ZXYsAHTpImVkYAOsSnQmYl9WUAAxV1AAXlAAbwBfAG5vPwCgmlg9SCCAIVxKGPjkixBrW1Z7R0ZUPUEfDy8Nf0D4iNcAGlB8woTQK0pYZFAAcjdgF1gRiytmPTpULPbYAAoASmLMWfn0Rb1ugvXNzCA

[nicolo-ribaudo]

Oh thanks 🙃

[sapphi-red]

Thanks 🙏

[fatcerberus]

Also, tip: isolatedModules is redundant if you're already using verbatimModuleSyntax - the latter implies the former