Addon-docs: Story source not shown when a variable named parameters is declared within CSF story

[enagy27]

Describe the bug
"No code available" is shown in docs preview when a variable, parameters, is declared at the top level in a CSF file.

To Reproduce
Uncomment the commented lines in this code snippet:

import React from 'react';
import { text } from '@storybook/addon-knobs';
import FormatSentence from '.';
// import { packageName } from '../../constants/stories';

// const componentSubtitle = `import FormatSentence from '${packageName}/lib/elements/format_sentence';`;

// const parameters = {
//   componentSubtitle,
// };

export const basic = () => {
  const sentence = text('sentence', 'This is a \uE000test\uE001 sentence.');
  return <FormatSentence sentence={sentence} />;
};

export default {
  title: 'Elements|FormatSentence',
  component: FormatSentence,
  // parameters,
};

Expected behavior
Both the commented and uncommented version of the snippet should behave the same.

System:
Environment Info:

System:
OS: macOS 10.14.5
CPU: (16) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
Binaries:
Node: 10.16.0 - /usr/local/opt/node@10/bin/node
Yarn: 1.17.3 - ~/workspace/component-library/node_modules/.bin/yarn
npm: 6.5.0 - ~/workspace/component-library/node_modules/.bin/npm
Browsers:
Chrome: 76.0.3809.132
Safari: 12.1.1
npmPackages:
@storybook/addon-a11y: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/addon-actions: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/addon-docs: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/addon-knobs: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/addon-links: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/addon-viewport: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/addons: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/preset-scss: 1.0.2 => 1.0.2
@storybook/preset-typescript: 1.1.0 => 1.1.0
@storybook/react: ^5.2.0-rc.11 => 5.2.0-rc.11
@storybook/source-loader: 5.2.0-rc.11 => 5.2.0-rc.11
@storybook/theming: ^5.2.0-rc.11 => 5.2.0-rc.11

[shilman]

@enagy27 Can repro. @enagy27 There's something about the source-loader generated code that doesn't like the parameters variable.

[patdryburgh]

@shilman Just wanted to let you know that I'm experiencing this as well, but I haven't added a parameters variable to any of my default exports.

[shilman]

@patdryburgh can you try the latest 5.3 prerelease on the next NPM tag and let me know more details if it still fails? we've made a handful of improvements to the source-loader during the alpha

[tolerance-go]

same problem, and I use storiesOf method, still is not ok

tried to upgrade "@ storybook / source-loader": "^ 5.3.0-rc.12", not solved

[shilman]

@tolerance-go do you have a repro?

[tolerance-go]

@shilman https://github.com/tolerance-go/markv/blob/d53c41486275730118731e932a456dad6abd73aa/src/components/MarkdownEditor/stories/index.stories.js#L15

i upgraded to CSF ​​story export，and all the packages have been upgraded to ^ 5.3.0-rc.12，still shown "No code available"

[shilman]

@tolerance-go Source-loader doesn't support fully dynamic titles. Please use a string constant or template literal.

export default {
  title: "components|MarkdownEditor",
  // title: route,
  component: MarkdownEditor
};

[whatwg6]

@tolerance-go Source-loader doesn't support fully dynamic titles. Please use a string constant or template literal.

export default {
  title: "components|MarkdownEditor",
  // title: route,
  component: MarkdownEditor
};

😔

[shilman]

We’re cleaning house! Storybook has changed a lot since this issue was created and we don’t know if it’s still valid.

Please open a new issue referencing this one if:

• this is still a problem in SB 7.x
• you can provide a consistent reproduction in 7.x (at https://storybook.new/ or per repro docs).