• Rollup Plugin Name: @rollup/plugin-typescript
• Rollup Plugin Version: 11.1.5
• Rollup Version: 4.9.0
• Operating System (or Browser): Ubuntu
• Node Version: 16.20
• Link to reproduction: https://github.com/ericmorand/rollup-plugin-typescript-issue-2

Expected Behavior

In the reproduction repository, we find 3 TS files:

• src/index.ts, the entry point
• src/valid.ts, imported by the entry point
• src/invalid.ts, containing non valid TypeScript syntax and imported by neither src/index.ts or src/valid.ts

When executing rollup on src/index.ts, the build should be successful since the src/invalid.ts file is not imported.

Actual Behavior

The build is unsuccessful, and the error suggests that src/invalid.ts is syntax-checked by the plugin even though it is not part of the dependency graph of the entry point:

$ npx rollup -i src/index.ts -p @rollup/plugin-typescript
npm WARN cli npm v10.2.4 does not support Node.js v16.20.2. This version of npm supports the following node versions: `^18.17.0 || >=20.5.0`. You can find the latest version at https://nodejs.org/.

src/index.ts → stdout...
var foo = 5;

console.log(foo);
(!) Plugin typescript: @rollup/plugin-typescript TS2304: Cannot find name 'foo'.
src/invalid.ts: (1:1)

1 foo
  ~~~

Additional Information

Note that the behaviour of tsc is correct in that regard:

$ tsc src/index.ts

No error is emitted and src/index.ts and src/valid.ts are successfully compiled.

So the error is coming from the plugin, not from the TypeScript compiler.