apple / sourcekit-lsp

Multi-line collections cannot be folded at all
Individual cases in a switch cannot be folded at all
This range folds entirely into a single line when only the comment should be folded; instead, the first line of the decl right below it is also collapsed.
Here, the folding marker is incorrectly on the line above the return statement. It is in the correct spot if the comment is removed. It behaves just like the above, where the following line is consumed by folding the comment. I'm guessing this implies all comments should be foldable, but that if a foldable statement exists below a comment, it mistakenly interferes with the ability to fold that statement.
Trailing )'s are not folded up the way trailing }'s are

Unless they're preceded by a }:

Edit: Adding more below as I come across them

Multiline function/init declarations, such as

 func someMethodWithLotsOfArgs( <--- this part
     arg1: T,
     arg2: U,
     arg3: V,
     arg4: W,
     ...
 ) {                            <--- down to here
     ...
 }

Tracked in Apple’s issue tracker as rdar://116877123

I think the folding issues with comment should be fixed by #804 but the other issues are definitely also ones we should fix.

If anyone is interesting in fixing these: The folding ranges are computed in

sourcekit-lsp/Sources/SourceKitLSP/Swift/SwiftLanguageServer.swift

Line 659 in d043dc0

    
           public func foldingRange(_ req: FoldingRangeRequest) async throws -> [FoldingRange]? {

, which is a fairly isolated SwiftSyntax visitor that doesn’t require too much outside knowledge apart from swift-syntax trees.

Tests live in https://github.com/apple/sourcekit-lsp/blob/main/Tests/SourceKitLSPTests/FoldingRangeTests.swift

Code folding improvements + bugs