0. Relevant Settings:

   "go.autocompleteUnimportedPackages": true 

1. Type the following program

package main //#include <stdlib.h> import "C" func main() { fmt } 

2. Place cursor behind "fmt"
3. Type "." The Intellisense window should pop up with suggestions.
4. Accept any suggestion (e.g. "Errorf")
5. The import statement will be rewritten to

//#include <stdlib.h> import (	"fmt"	"C" ) 

However this breaks the magic of import "C" which uses the preceding comment.

When converting import lines to a parenthesized import block, vscode-go should insert the "import (" before the comment lines immediately preceding (i.e. with no empty lines in between) the first import (if there are any).