// 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")

	}

	x.typ = typ
}

// typ type-checks the type expression e and returns its type, or Typ[Invalid].
// The type must not be an (uninstantiated) generic type.
func (check *Checker) typ(e syntax.Expr) Type {
	return check.definedType(e, nil)
}

// varType type-checks the type expression e and returns its type, or Typ[Invalid].
// The type must not be an (uninstantiated) generic type and it must not be a
// constraint interface.

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.

	{"type t struct{f int}", "t", "type p.t struct{f int}", false},
	{"type t func(int)", "t", "type p.t func(int)", false},
	{"type t[P any] struct{f P}", "t", "type p.t[P any] struct{f P}", false},
	{"type t[P any] struct{f P}", "t.P", "type parameter P any", false},
	{"type C interface{m()}; type t[P C] struct{}", "t.P", "type parameter P p.C", false},

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)
}

func (a *Alias) Obj() *TypeName { return a.orig.obj }

func (a *Alias) String() string { return TypeString(a, nil) }

// 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.

	recvTParamMap map[*syntax.Name]*TypeParam // maps blank receiver type parameters to their type
	brokenAliases map[*TypeName]bool          // set of aliases with broken (not yet determined) types
	unionTypeSets map[*Union]*_TypeSet        // computed type sets for union types
	mono          monoGraph                   // graph for detecting non-monomorphizable instantiation loops