Don't blow the stack when traversing deeply nested sequential expressions

[brianrourkeboll]

Description

Fixes one of the problems discovered in #16869 (#16869 (comment)).

Sequential expressions are more likely than most other expression kinds to be very deeply nested, e.g., in very large list or array expressions. Since traverseSynExpr is not tail-recursive, we must treat sequential expressions specially to avoid blowing the stack.

(This change isn't specific to the parens analyzer; the parens analyzer was just more likely to run into the underlying problem, since it always traverses each file's full AST.)

With this change in place, I can now successfully apply the "fix all in document" action to remove unnecessary parens in ServiceDeclarationLists.fs:

I can even apply the fix inside of the ~17,000-line array expression in pars.fs:

Checklist

• Test cases added
  • The existing tests that exercise this pathway still pass.
  • Very big array expr test: beef3a6.
• Release notes entry updated

[github-actions]

❗ Release notes required

---

✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
src/Compiler	docs/release-notes/.FSharp.Compiler.Service/8.0.300.md

[psfinaki]

Good stuff, thanks a lot. If that megatest is easy to add, go ahead, would be also useful :)

[psfinaki]

/azp run

[azure-pipelines]

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