package syntax

import "go/constant"

// A Type represents a type of Go.
// All types implement the Type interface.
// (This type originally lived in types2. We moved it here
// so we could depend on it from other packages without
// introducing an import cycle.)
type Type interface {
	// Underlying returns the underlying type of a type.
	// Underlying types are never Named, TypeParam, or Alias types.
	//

// This file contains various functionality that is
// different between go/types and types2. Factoring
// out this code allows more of the rest of the code
// to be shared.

package types2

import (
	"cmd/compile/internal/syntax"
	"go/constant"
	"go/token"
)

const isTypes2 = true

// cmpPos compares the positions p and q and returns a result r as follows:
//

// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package types2

import (
	"cmd/compile/internal/syntax"
	"fmt"
)

// This file should not be copied to go/types.  See go.dev/issue/67477

// RenameResult takes an array of (result) fields and an index, and if the indexed field

// license that can be found in the LICENSE file.

// This file contains various functionality that is
// different between go/types and types2. Factoring
// out this code allows more of the rest of the code
// to be shared.

package types

import (
	"go/ast"
	"go/constant"
	"go/token"
)

const isTypes2 = false

// cmpPos compares the positions p and q and returns a result r as follows:
//
// r <  0: p is before q

// type of all types in its type set if it exists, or nil otherwise. If the
// type set contains only unrestricted and restricted channel types (with
// identical element types), the single underlying type is the restricted
// channel type if the restrictions are always the same, or nil otherwise.
func coreType(t Type) Type {
	t = Unalias(t)
	tpar, _ := t.(*TypeParam)
	if tpar == nil {
		return under(t)

// license that can be found in the LICENSE file.

package types2

import (
	"fmt"
	"go/version"
	"internal/goversion"
)

// A goVersion is a Go language version string of the form "go1.%d"
// where d is the minor version number. goVersion strings don't
// contain release numbers ("go1.20.1" is not a valid goVersion).
type goVersion string

	return t.Underlying()
}

// If t is not a type parameter, coreType returns the underlying type.
// If t is a type parameter, coreType returns the single underlying
// type of all types in its type set if it exists, or nil otherwise. If the
// type set contains only unrestricted and restricted channel types (with
// identical element types), the single underlying type is the restricted
// channel type if the restrictions are always the same, or nil otherwise.

// This file implements (error and trace) message formatting support.

package types2

import (
	"bytes"
	"cmd/compile/internal/syntax"
	"fmt"
	"strconv"
	"strings"
)

func sprintf(qf Qualifier, tpSubscripts bool, format string, args ...any) string {
	for i, arg := range args {
		switch a := arg.(type) {
		case nil:
			arg = "<nil>"
		case operand:
			panic("got operand instead of *operand")

func nextID() uint64 { return uint64(lastID.Add(1)) }

// A TypeParam represents a type parameter type.
type TypeParam struct {
	check *Checker  // for lazy type bound completion
	id    uint64    // unique id, for debugging only
	obj   *TypeName // corresponding type name
	index int       // type parameter index in source order, starting at 0
	bound Type      // any type, but underlying is eventually *Interface for correct programs (see TypeParam.iface)
}

// Underlying returns the [underlying type] of the alias type a, which is the
// underlying type of the aliased type. Underlying types are never Named,
// TypeParam, or Alias types.
//
// [underlying type]: https://go.dev/ref/spec#Underlying_types.
func (a *Alias) Underlying() Type { return unalias(a).Underlying() }

// Origin returns the generic Alias type of which a is an instance.