Unescaping f# method names

[nohwnd]

Fancy f# method names with `` `` are escaping according to some rules, and to make managed name full compatible we need to fully unescape. #4969 fixes the most painful problem that prevents discovering completely. But in ideal case the CIL name should be fully unescaped so it can be found through reflection.

---

I have run a few manual tests and here are the characters that gets transformed (not exhaustive list):

• \ escaped as \\
• ' escaped as \'
• " escaped as \"
• @ escaped as @5

I will look at more cases now.

Originally posted by @Evangelink in #4969 (comment)

AB#2020980

[testplatform-bot]

✅ Successfully linked to Azure Boards work item(s):

• User Story 2020980

[nohwnd]

Spec says:
3.4 Identifiers and Keywords

Any sequence of characters that is enclosed in double-backtick marks ( ), excluding newlines,
tabs, and double-backtick pairs themselves, is treated as an identifier. Note that when an identifier is
used for the name of a types, union type case, module, or namespace, the following characters are
not allowed even inside double-backtick marks:
‘.', '+', '$', '&', '[', ']', '/', '\', '*', '"', '`'
All input files are currently assumed to be encoded as UTF-8. See the C# specification for a list of the
Unicode characters that are accepted for the Unicode character classes \Lu, \Li, \Lt, \Lm, \Lo, \Nl,
\Pc, \Mn, \Mc, and \Cf.

https://fsharp.org/specs/language-spec/4.1/[FSharpSpec-4.1-latest.pdf](https://fsharp.org/specs/language-spec/4.1/FSharpSpec-4.1-latest.pdf)

member this.`` . + - = $ & [ ] \ / * @ ' ` " % ( ) ^ `` () =
Experimenting with the chars above and few more only ` ' " \ look to be escaped for methods:

@Amaury how did you get @ to become @5?

[Amaury]

Not the right Amaury... Try again 😉

[nohwnd]

This is not an issue, I misinterpreted what the parser is doing. We only need to handle ' correctly, which we do in #4969