func f(x T) T { return foo.F(x) }
`
	fset := token.NewFileSet()
	f := mustParse(fset, src)
	files := []*ast.File{f}

	// type-check using all possible importers
	for _, compiler := range []string{"gc", "gccgo", "source"} {
		errcount := 0
		conf := Config{
			Error: func(err error) {
				// we should only see the import error
				if errcount > 0 || !strings.Contains(err.Error(), "could not import") {

	return x
}

// toType converts from a *rtype to a Type that can be returned
// to the client of package reflect. In gc, the only concern is that
// a nil *rtype must be replaced by a nil Type, but in gccgo this
// function takes care of ensuring that multiple *rtype for the same
// type are coalesced into a single Type.
//
// toType should be an internal detail,
// but widely used packages access it using linkname.