Go language syntax for function with generic not properly highlighted

[alexr00]

Originally from @uudashr in microsoft/vscode#146313

• VS Code Version: 1.65.2
• OS Version: Darwin arm64 20.6.0

Steps to Reproduce:

1. Create new file math.go

package generics

type Number interface {
	int64 | float64
}

func SumInts(m map[string]int64) int64 {
	var s int64
	for _, v := range m {
		s += v
	}
	return s
}

func SumFloats(m map[string]float64) float64 {
	var s float64
	for _, v := range m {
		s += v
	}
	return s
}

func SumIntsOrFloats[K comparable, V int64 | float64](m map[K]V) V {
	var s V
	for _, v := range m {
		s += v
	}
	return s
}

func SumNumbers[K comparable, V Number](m map[K]V) V {
	var s V
	for _, v := range m {
		s += v
	}
	return s
}

The generic function is inside the red rectangle. We can see the expected should be like on the green rectangle.

[hyangah]

Users who use vscode-go extension can enable richer syntax highlighting through the semantic tokens provided by gopls. But I think supporting basic syntax highlighting for Go by default (without extra extension installation or running gopls process which isn't supported in web-based IDEs like github.dev or vscode.dev) will be ideal.

@alexr00 AFAIK TextMate-based grammar system has limitation and people desired to get Tree-sitter-based syntax highlighting. I thought VS Code team was looking into the tree-sitter option https://github.com/microsoft/vscode-anycode already. Does VS Code have plan to leverage the work in vscode-anycode and have generics support there (if it doesn't have)?

[alexr00]

It's still an exploration, we don't have any plan in place switch to tree-sitter right now.