x/tools/gopls: support type parameters for function literal snippet completions #50623
Description
Given the following code:
type Tree[T any] struct{}
func (tree Tree[T]) Do(f func(s T)) {}
func _() {
var t Tree[string]
t.Do(fun) // trigger completion
}The current completion that gopls gives for the func(...) {} snippet option is: func(s T) {}, but that is incorrect as T is not really valid. The correct solution would be whatever type was instantiated at compile time, so the completion in the example above should be func(s string) {}