fix(type-utils): intersection types involving readonly arrays are now handled in most cases

[RebeccaStevens]

PR Checklist

• Addresses an existing issue: fixes [isTypeReadonly] Intersections involving a readonly array fail #4428
• That issue was marked as accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

isTypeReadonly now handles intersection involving readonly arrays and tuples properly in most cases.

The cases that aren't handled are those of that intersect a readonly array with an object that shares mutable properties with the array. For example:

type Test = ReadonlyArray<string> & { length: string; };

Handling this in the general case may not be possible as we can't treat readonly arrays in nested intersections properly (at least not without a lot of work).
As a workaround, users can just wrap their intersection in Readonly if they come across this case.

Note: This PR builds off #4416

[nx-cloud]

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[typescript-eslint]

Thanks for the PR, @RebeccaStevens!

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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[bradzacher]

Thanks so much for handling this!
I merged your test PR first - just needs the conflict resolved and we can merge this!

[codecov]

Codecov Report

Merging #4429 (bd475fb) into main (f4016c2) will decrease coverage by 1.81%.
The diff coverage is 93.33%.

@@            Coverage Diff             @@
##             main    #4429      +/-   ##
==========================================
- Coverage   94.54%   92.73%   -1.82%     
==========================================
  Files         147      161      +14     
  Lines        7851     8160     +309     
  Branches     2516     2621     +105     
==========================================
+ Hits         7423     7567     +144     
- Misses        234      392     +158     
- Partials      194      201       +7     

Flag	Coverage Δ
unittest	92.73% <93.33%> (-1.82%)	⬇️

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

Impacted Files	Coverage Δ
packages/type-utils/src/isTypeReadonly.ts	84.69% <93.33%> (ø)
packages/type-utils/src/typeFlagUtils.ts	83.33% <0.00%> (ø)
packages/type-utils/src/propertyTypes.ts	87.50% <0.00%> (ø)
packages/type-utils/src/containsAllTypesByName.ts	0.00% <0.00%> (ø)
packages/type-utils/src/getContextualType.ts	0.00% <0.00%> (ø)
packages/type-utils/src/getTokenAtPosition.ts	0.00% <0.00%> (ø)
...ges/type-utils/src/getConstrainedTypeAtLocation.ts	0.00% <0.00%> (ø)
packages/type-utils/src/isUnsafeAssignment.ts	84.00% <0.00%> (ø)
packages/type-utils/src/getSourceFileOfNode.ts	0.00% <0.00%> (ø)
packages/type-utils/src/getTypeArguments.ts	25.00% <0.00%> (ø)
... and 5 more

[bradzacher]

ugh. git is the worst.