Add symbolName property for some syntax nodes

[Matejkob]

FunctionDecl, InitializerDecl, SubscriptDecl, EnumCaseElement, and MacroDecl gained a new computed property: symbolName

The symbolName property provides a string representation of the declaration's name along with its parameter labels. For example, a function func greet(name: String) will have the symbol name greet(name:).

Resolves #2488

[Matejkob]

Which other nodes should have a symbolName property?

1. enum, protocol, struct, class, actor?
2. typealias?
3. property - this one for sure.
4. deinit ?
5. macro ?
6. operator ?

[ahoppen]

I think it only makes sense to offer it for nodes that have a FunctionParameterClauseSyntax or EnumCaseParameterClauseSyntax and thus need handling of argument labels. That is

• FunctionDeclSyntax
• InitializerDeclSyntax
• MacroDeclSyntax
• SubscriptDeclSyntax
• EnumCaseDeclSyntax

[Matejkob]

Depending on: #2593

[ahoppen]

Thank you. Looks great, I’m just being nitpicky again.

[Matejkob]

Thanks for the review Alex 🫶

[ktoso]

@swift-ci please smoke test

[hamishknight]

A small nit over the naming in the documentation, but otherwise this LGTM

[hamishknight]

Nit: These are called argument labels in TSPL, and we have e.g SyntaxClassification.argumentLabel, I think we probably ought to be consistent.

Suggested change

	- Description: The `symbolName` property provides a string representation of the declaration's name along with its parameter labels. For example, a function `func greet(name: String)` will have the symbol name `greet(name:)`.
	- Description: The `symbolName` property provides a string representation of the declaration's name along with its argument labels. For example, a function `func greet(name: String)` will have the symbol name `greet(name:)`.

[hamishknight]

Suggested change

	/// The symbol name is a string representation of the function name along with its parameter labels.
	/// The symbol name is a string representation of the function name along with its argument labels.

[hamishknight]

Suggested change

	/// The symbol name is a string representation of the initializer along with its parameter labels.
	/// The symbol name is a string representation of the initializer along with its argument labels.

[hamishknight]

Suggested change

	/// The symbol name is a string representation of the subscript along with its parameter labels.
	/// The symbol name is a string representation of the subscript along with its argument labels.

[hamishknight]

Suggested change

	/// The symbol name is a string representation of the macro name along with its parameter labels.
	/// The symbol name is a string representation of the macro name along with its argument labels.

[hamishknight]

Suggested change

	/// Generates the symbol name by combining the base name and parameter labels.
	/// Generates the symbol name by combining the base name and argument labels.

[rintaro]

This resembles DeclName in C++ compiler.
I think we should also make it a struct, like:

struct SymbolBaseName {
  enum Kind { case normal, subscript, initializer, deinitializer }
  var asString: String {get}
  var kind: Kind {get}
  var isOperator: Bool {get}
}
struct SymbolName {  
  var asString: String {get}
  var baseName: SymbolBaseName {get}
  var argumentLabels: some Collection<String> {get}
}

WDYT?

[ahoppen]

That is a great idea, @rintaro.