type Importer interface {
	// Import returns the imported package for the given import path.
	// The semantics is like for ImporterFrom.ImportFrom except that
	// dir and mode are ignored (since they are not present).
	Import(path string) (*Package, error)
}

// ImportMode is reserved for future use.
type ImportMode int

// An ImporterFrom resolves import paths to packages; it

type Importer interface {
	// Import returns the imported package for the given import path.
	// The semantics is like for ImporterFrom.ImportFrom except that
	// dir and mode are ignored (since they are not present).
	Import(path string) (*Package, error)
}

// ImportMode is reserved for future use.
type ImportMode int

// An ImporterFrom resolves import paths to packages; it

package types2_test

import (
	"cmd/compile/internal/syntax"
	"fmt"
	"internal/testenv"
	"sort"
	"testing"

	. "cmd/compile/internal/types2"
)

type resolveTestImporter struct {
	importer ImporterFrom
	imported map[string]bool
}

func (imp *resolveTestImporter) Import(string) (*Package, error) {
	panic("should not be called")
}

package types_test

import (
	"fmt"
	"go/ast"
	"go/importer"
	"go/token"
	"internal/testenv"
	"slices"
	"testing"

	. "go/types"
)

type resolveTestImporter struct {
	importer ImporterFrom
	imported map[string]bool
}

func (imp *resolveTestImporter) Import(string) (*Package, error) {
	panic("should not be called")
}

	return ForCompiler(token.NewFileSet(), compiler, lookup)
}

// Default returns an Importer for the compiler that built the running binary.
// If available, the result implements [types.ImporterFrom].
func Default() types.Importer {
	return For(runtime.Compiler, nil)
}

// gc importer

type gcimports struct {
	fset     *token.FileSet
	packages map[string]*types.Package
	lookup   Lookup
}

pkg go/types, method (*Package) SetName(string)
pkg go/types, type ImportMode int
pkg go/types, type ImporterFrom interface { Import, ImportFrom }
pkg go/types, type ImporterFrom interface, Import(string) (*Package, error)
pkg go/types, type ImporterFrom interface, ImportFrom(string, string, ImportMode) (*Package, error)
pkg html/template, func IsTrue(interface{}) (bool, bool)

	} else {
		// ordinary import
		var err error
		if importer := check.conf.Importer; importer == nil {
			err = fmt.Errorf("Config.Importer not installed")
		} else if importerFrom, ok := importer.(ImporterFrom); ok {
			imp, err = importerFrom.ImportFrom(path, dir, 0)
			if imp == nil && err == nil {
				err = fmt.Errorf("Config.Importer.ImportFrom(%s, %s, 0) returned nil but no error", path, dir)
			}
		} else {

	} else {
		// ordinary import
		var err error
		if importer := check.conf.Importer; importer == nil {
			err = fmt.Errorf("Config.Importer not installed")
		} else if importerFrom, ok := importer.(ImporterFrom); ok {
			imp, err = importerFrom.ImportFrom(path, dir, 0)
			if imp == nil && err == nil {
				err = fmt.Errorf("Config.Importer.ImportFrom(%s, %s, 0) returned nil but no error", path, dir)
			}
		} else {

}

// TODO(gri) Once we are certain that typeHash is correct in all situations, use this version of caseTypes instead.
// (Currently it may be possible that different types have identical names and import paths due to ImporterFrom.)
//
// func (check *Checker) caseTypes(x *operand, xtyp *Interface, types []syntax.Expr, seen map[string]syntax.Expr) (T Type) {
// 	var dummy operand
// L:
// 	for _, e := range types {

}

// TODO(gri) Once we are certain that typeHash is correct in all situations, use this version of caseTypes instead.
// (Currently it may be possible that different types have identical names and import paths due to ImporterFrom.)
//
// func (check *Checker) caseTypes(x *operand, xtyp *Interface, types []ast.Expr, seen map[string]ast.Expr) (T Type) {
// 	var dummy operand
// L:
// 	for _, e := range types {