Type information 'leaking' between models

[jjhuff]

When calling setModel, it seems like typescript info isn't being cleared properly.
Originally filed here: suren-atoyan/monaco-react#308

monaco-editor version: 0.30.1 (playground version)
Browser: Chrome M96
OS: Linux
Playground code that reproduces the issue:

const model1 = monaco.editor.createModel(`
const foo=1;
`, 'javascript', 'root/js/file1.js');

const model2 = monaco.editor.createModel(`
const foo=2;
const bar=3;
`, 'javascript', 'root/js/file2.js');

const editor = monaco.editor.create(document.getElementById('container'), {
    model: model1,
});

setTimeout(() => {
  editor.setModel(model2);
}, 500);

setTimeout(() => {
  editor.setModel(model1);
}, 1000);

After the snipped toggles the models, try typing const bar. You'll get bar as a completion choice even though bar is defined in the non-current model.

[alexdima]

This is as designed. There is a single language service (a conceptual equivalent of a single tsconfig.json) instantiated per page.

[jjhuff]

Gotcha. I've been playing with this scenario in VSCode. It seems like the language service behavior matches the compiler when not using modules (I just added export {} to my files). They assume global scope.

However, when using modules, the errors regarding 'foo' go away. However, bar is still suggested as a completion in file1, even though it's not defined in that file.