Report code coverage fails when using experimental mock feature

[didiercolens]

Version

v23.11.0

Platform

Darwin Kernel Version 24.4.0 (ARM) but likely not relevant

Subsystem

test_runner

What steps will reproduce the bug?

Create the 3 below files in a folder and run node --experimental-transform-types --experimental-test-module-mocks --test --experimental-test-coverage --test-reporter=spec --test-reporter-destination=stdout ./foo.test.mts

files

bar.mts

export default function bar() {
  return 'original bar';
}

foo.mts

import bar from './bar.mts';

export const foo = () => bar();

foo.test.mts

import assert from 'node:assert/strict';
import { before, describe, it, mock } from 'node:test';

describe('foo', { concurrency: true }, () => {
  let barMock = mock.fn();
  let foo;

  before(async () => {
    const barNamedExports = await import('./bar.mts')
      .then(({ default: _, ...rest }) => rest);

    mock.module('./bar.mts', {
      defaultExport: barMock,
      namedExports: barNamedExports,
    });

    ({ foo } = await import('./foo.mts'));
  });

  it('should do the thing', () => {
    barMock.mock.mockImplementationOnce(()  => 42);

    assert.equal(foo(), 42);
  });
});

How often does it reproduce? Is there a required condition?

always

What is the expected behavior? Why is that the expected behavior?

tests pass and test coverage is displayed

What do you see instead?

tests pass but test coverage failed:

(node:49928) ExperimentalWarning: Type Stripping is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
(node:49928) ExperimentalWarning: Module mocking is an experimental feature and might change at any time
▶ foo
  ✔ should do the thing (0.46475ms)
✔ foo (36.605917ms)
ℹ Warning: Could not report code coverage. TypeError: Cannot read properties of undefined (reading 'startOffset')
ℹ tests 1
ℹ suites 1
ℹ pass 1
ℹ fail 0
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 155.707375

Additional information

looks similar to #55054