try reproducing incorrect coverage when loading querystring

package.json

@@ -11,6 +11,7 @@
   },
   "scripts": {
     "test": "cross-env TS_NODE_SKIP_PROJECT=true node ./bin/c8.js mocha --timeout=10000 ./test/*.js",
+    "test-loader": "cross-env TS_NODE_SKIP_PROJECT=true node ./bin/c8.js mocha --timeout=10000 ./test/source-resolved-from-loader.js",
     "coverage": "cross-env TS_NODE_SKIP_PROJECT=true node ./bin/c8.js --check-coverage mocha --timeout=10000 ./test/*.js",
     "test:snap": "cross-env CHAI_JEST_SNAPSHOT_UPDATE_ALL=true npm test",
     "fix": "standard --fix",

test/fixtures/all/vanilla/main.querystring-import.mjs

@@ -0,0 +1,38 @@
+import module from 'node:module'
+
+async function resolve (moduleId, context, next) {
+  const result = await next(moduleId, context);
+  const url = new URL(result.url)
+  url.searchParams.set('randomSeed', Math.random());
+  result.url = url.href;
+  return result;
+}
+
+function load(url, context, next) {
+  if (url.includes('main.js')) {
+    const loadedId = url.replace('main.js', 'loaded.js')
+
+    return {
+      shortCircuit: true,
+      format: 'module',
+      source: `import loaded from "${loadedId}";loaded()`,
+    };
+  }
+
+  if (url.includes('loaded.js')) {
+    return {
+      shortCircuit: true,
+      format: 'module',
+      source: 'export default () => true',
+    };
+  }
+
+  return next(url, context);
+}
+
+module.register && module.register(`
+data:text/javascript,
+export ${encodeURIComponent(load)}
+export ${encodeURIComponent(resolve)}`.slice(1))
+
+export default import('./main.js?qs=1')

test/source-resolved-from-loader.js

@@ -0,0 +1,50 @@
+/* global describe, before, beforeEach, it */
+
+const { spawnSync } = require('child_process')
+const c8Path = require.resolve('../bin/c8')
+const nodePath = process.execPath
+const tsNodePath = './node_modules/.bin/ts-node'
+const chaiJestSnapshot = require('chai-jest-snapshot')
+const rimraf = require('rimraf')
+const nodemodule = require('node:module')
+
+require('chai')
+  .use(chaiJestSnapshot)
+  .should()
+
+before(cb => rimraf('tmp', cb))
+
+beforeEach(function () {
+  chaiJestSnapshot.configureUsingMochaContext(this)
+})
+
+;[false, true].forEach((mergeAsync) => {
+  const title = mergeAsync ? 'c8+loader mergeAsync' : 'c8+loader'
+  describe(title, () => {
+    if (nodemodule.register) {
+      it('reports coverage for query-loaded js files, with accuracy', async () => {
+        const { output } = spawnSync(nodePath, [
+          c8Path,
+          '--temp-directory=tmp/vanilla-all',
+          '--clean=false',
+          '--all=true',
+          '--include=test/fixtures/all/vanilla/**/*.js',
+          '--exclude=**/*.ts', // add an exclude to avoid default excludes of test/**
+          `--merge-async=${mergeAsync}`,
+          nodePath,
+          '--experimental-default-type=module',
+          require.resolve('./fixtures/all/vanilla/main.querystring-import.mjs')
+        ])
+
+        // test fails if loaded row looks like this
+        //  loaded.js   |     100 |      100 |     100 |     100 | 
+        output.toString('utf8')
+          .split('\n')
+          .filter(l => l.includes(' loaded.js'))[0]
+          .split('|').filter(l => /\d/.test(l))
+          .every(l => !l.includes(100))
+          .should.equal(true)
+      })
+    }
+  })
+})