Use augmentsSyntaxTokens parameter instead of reportSyntacticHighlightInSemanticTokens in initialization request #2767

Description

Starting with Swift 6.4, a new parameter has been added to the initialization request: reportSyntacticHighlightInSemanticTokens. This new parameter is not part of the official lsp specification, and is placed in the initializationOptions section of the initialization request (user provided initialization options).

When the reportSyntacticHighlightInSemanticTokens is false (the default), sourcekit-lsp does not include syntactic highlight in its response to the textDocument/semanticTokens/full request. It is assumed that the client already has its own syntactic highlighting, and sourcekit-lsp should only augment it with semantic tokens.

The official lsp specification already has similar parameter: augmentsSyntaxTokens in semanic tokens client capabilities section. This parameter is currently not used by sourcekit-lsp.

See these parameters placement in the params of the initialization request (note that when one parameter is true, the other is false for the same effect):

{
    "initializationOptions": {
        "reportSyntacticHighlightInSemanticTokens": true
    },
    "capabilities": {
        "textDocument": {
            "semanticTokens": {
                "augmentsSyntaxTokens": false
            }
        }
    }
}

This feature request proposes using the officially supported augmentsSyntaxTokens parameter instead of custom reportSyntacticHighlightInSemanticTokens.