Why do you need the ImportSpecs? What is the use case?

Note that this function was primarily written for filtering the AST for use with go/doc and eventually displaying it via godoc. Changing the semantics may have unintended consequences.

I'm writing a code writing tool that uses AST analysis and transformation to produce specific implementations of generic algorithms on matching types. Part of this process is analyzing what imports from the 'type provider' file need to be added to the specific implementation of the generic code in order to be correct.

E.g.

Type Provider

package main
import "go/ast"
type Decls []*ast.GenDecl

Generic Algorithm

package main
type Collection []interface
func (c Collection) Filter(fn func(interface{}) bool) (result Collection) {}

Expected Result

package main
import "go/ast"
func (c Decls) Filter(fn func(*ast.GenDecl) bool) (result Decls) {}

It honestly shouldn't be hard to roll my own, but ast.FilterFile at least presents itself as the canonical implementation of what I'm trying to do. It's ok if it can't change, but maybe the documentation should be updated to indicate the limitation if that's the case.

It may actually be easier to simply filter the imports yourself. I'd rather not change/add to this code at this point (the ast.FilterFile function is one of the very oldest pieces of library code and a new implementation would look rather different).

Let's leave the issue open so that we remember to document it eventually. Thanks.

Sounds good, thanks!