fix(eslint-plugin): [explicit-function-return-type, explicit-module-boundary-types] improved checking for allowHigherOrderFunctions option

[yeonjuan]

PR Checklist

• Addresses an existing open issue: fixes [explicit-function-return-type] Have to type every chain of higher order function  #928
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

The explicit-function-return-type's issue(#928) also occured in explicit-module-boundary-types because two rule use same util (explicitReturnTypeUtils.ts).

• online demo

export const foo = () => { // no lint error
  return (): void => {}
}

export const bar = () => { // lint error
  const baz = "baz";
  return (): void => { }
}

I changed the code to collect the return statements inside the function, pass them to explicitReturnTypeUtils, and check whether it is a highOrderFunction or not. (#894 (comment))

[typescript-eslint]

Thanks for the PR, @yeonjuan!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Attention: Patch coverage is 96.00000% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 87.35%. Comparing base (3ac824b) to head (68ebb69).
Report is 47 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8508      +/-   ##
==========================================
+ Coverage   87.14%   87.35%   +0.21%     
==========================================
  Files         251      252       +1     
  Lines       12272    12456     +184     
  Branches     3871     3914      +43     
==========================================
+ Hits        10694    10881     +187     
+ Misses       1306     1304       -2     
+ Partials      272      271       -1     

Flag	Coverage Δ
unittest	87.35% <96.00%> (+0.21%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...-plugin/src/rules/explicit-function-return-type.ts	98.11% <100.00%> (+0.24%)	⬆️
.../eslint-plugin/src/util/explicitReturnTypeUtils.ts	97.70% <100.00%> (ø)
...plugin/src/rules/explicit-module-boundary-types.ts	91.54% <90.00%> (-0.88%)	⬇️

... and 24 files with indirect coverage changes

[JoshuaKGoldberg]

By the way @yeonjuan, you are a hero for merging main in so much 😄. I filed #8610 to track establishing a standard so you & other PR authors don't feel a need to spend your time on that.

[yeonjuan]

@JoshuaKGoldberg
Thanks for sharing. I thought the notifications wouldn't go to the folk because I push to a forked repo.... I will follow the recommendations going forward.

[JoshuaKGoldberg]

Love it, this is great! 🤩

Just the one note on a return outside a function. Otherwise really nicely crafted.

[JoshuaKGoldberg]

Oh and just a heads up, although there isn't a technical Git merge conflict, #8019 being merged is giving this a lint failure in CI.

/home/runner/work/typescript-eslint/typescript-eslint/packages/eslint-plugin/src/rules/explicit-function-return-type.ts
  117:14  error  Forbidden non-null assertion  @typescript-eslint/no-non-null-assertion

[JoshuaKGoldberg]