forceConsistentCasingInFileNames doesn't work as advertisted

[OliverJAsh]

Bug Report

🔎 Search Terms

• forceConsistentCasingInFileNames
• casing

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about forceConsistentCasingInFileNames

💻 Code

tsconfig.json:

{
  "compilerOptions": {
    "forceConsistentCasingInFileNames": true
  },
  "files": ["./src/main.ts"]
}

src/main.ts:

// Casing is incorrect here, but there's no type error (on macOS at least).
import { foo } from "./FOO";

console.log(foo);

src/foo.ts:

export const foo = 1;

🙁 Actual behavior

Testing on macOS (case insensitive file system), there is no type error (in my editor and when I run tsc).

🙂 Expected behavior

There should be a type error due to incorrect casing for import { foo } from "./FOO";, as per the documentation for forceConsistentCasingInFileNames:

When [forceConsistentCasingInFileNames] is set, TypeScript will issue an error if a program tries to include a file by a casing different from the casing on disk.

— https://www.typescriptlang.org/tsconfig#forceConsistentCasingInFileNames

[MartinJohns]

Or alternatively, the documentation should be fixed, because as far as I know the behaviour is intentional and will only warn about mixing casing within your code base (link to issue mentioning this missing).

You want #21736.

[OliverJAsh]

Thanks, that makes sense! In that case I think this is just a documentation issue.

[fatcerberus]

Current behavior may not be intentional: #21736 (comment)

[typescript-bot]

This issue has been marked as 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.