Warning or error when importing files from a project's own outDir

Search Terms

import, outDir, composit, TS5055

Suggestion

Add a specific warning/error when trying to import something from the projects own outDir.

Use Cases

Help track down files that are wrongly importing from it's own dist directory.
I don't know if there are valid use cases where you would want to do this but I can only think of (refactor) errors.

Examples

In a big refactor I moved a class from a project to a shared directory (compiled with composite: true, imported into projects with "references").
I made the following change without thinking because it satisfied the compiler.

- import mongoose from "../../shared/dist/mongo";
+ import mongoose from "../dist/mongo";

Everything seemed to work fine (no error was shown in vscode on the import line itself, and the now shared class worked) until the next week I notice the following errors when compiling the shared dir:

error TS5055: Cannot write file '.../shared/dist/interfaces/branch.d.ts' because it would overwrite input file.
error TS5055: Cannot write ...

I did not notice these errors while doing the refactor itself because the tsc -w for the shared directory was running in a forgotten terminal tab. A warning or error on the import line itself when doing something like this would save a lot of debugging time.

Checklist

My suggestion meets these guidelines: (this is my guess, don't know exactly what the change would entail)

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

The issue names no source files, tests, or compiler entry points. Reproduce the composite-project case by importing from the project's own outDir and observe the TS5055 failure, then trace how module resolution and diagnostics handle that import. Done means a specific warning or error points to the problematic import, with regression coverage.