return
		}

		// if both arguments are constants, the result is a constant
		if x.mode == constant_ && y.mode == constant_ {
			x.val = constant.BinaryOp(constant.ToFloat(x.val), token.ADD, constant.MakeImag(constant.ToFloat(y.val)))
		} else {
			x.mode = value
		}

		if check.recordTypes() && x.mode != constant_ {
			check.recordBuiltinType(call.Fun, makeSig(resTyp, x.typ, x.typ))
		}

import "go/types"
import "go/constant"

var _ = constant_.Kind
var constant = 23 // Use of new package name.

func f() {
	_ = constant_.MakeBool(true)
}
`,
	},

			return
		}

		// if both arguments are constants, the result is a constant
		if x.mode == constant_ && y.mode == constant_ {
			x.val = constant.BinaryOp(constant.ToFloat(x.val), token.ADD, constant.MakeImag(constant.ToFloat(y.val)))
		} else {
			x.mode = value
		}

		if check.recordTypes() && x.mode != constant_ {
			check.recordBuiltinType(call.Fun, makeSig(resTyp, x.typ, x.typ))
		}

// typexpr    <expr> (               <mode>                    )
//
// constant   <expr> (<untyped kind> <mode>                    )
// constant   <expr> (               <mode>       of type <typ>)
// constant   <expr> (<untyped kind> <mode> <val>              )
// constant   <expr> (               <mode> <val> of type <typ>)
//
// variable   <expr> (<untyped kind> <mode>                    )

// typexpr    <expr> (               <mode>                    )
//
// constant   <expr> (<untyped kind> <mode>                    )
// constant   <expr> (               <mode>       of type <typ>)
// constant   <expr> (<untyped kind> <mode> <val>              )
// constant   <expr> (               <mode> <val> of type <typ>)
//
// variable   <expr> (<untyped kind> <mode>                    )

	case constant.Float:
		i := constant.ToInt(x)
		if i.Kind() != constant.Int {
			v, _ := constant.Float64Val(x)
			return v
		}
		x = i
		fallthrough
	case constant.Int:
		if v, ok := constant.Int64Val(x); ok {
			return v
		}
		if v, ok := constant.Uint64Val(x); ok {
			return v
		}
	case constant.String:
		return constant.StringVal(x)
	case constant.Bool:

	switch typ := under(x.typ).(type) {
	case *Basic:
		if isString(typ) {
			valid = true
			if x.mode == constant_ {
				length = int64(len(constant.StringVal(x.val)))
			}
			// an indexed string always yields a byte value
			// (not a constant) even if the string and the
			// index are constant
			x.mode = value
			x.typ = universeByte // use 'byte' name
		}

	case *Array:
		valid = true
		length = typ.len

	switch typ := under(x.typ).(type) {
	case *Basic:
		if isString(typ) {
			valid = true
			if x.mode == constant_ {
				length = int64(len(constant.StringVal(x.val)))
			}
			// an indexed string always yields a byte value
			// (not a constant) even if the string and the
			// index are constant
			x.mode = value
			x.typ = universeByte // use 'byte' name
		}

	case *Array:
		valid = true
		length = typ.len

		return constant.MakeFloat64(f)
	}
	return nil
}

func fitsFloat64(x constant.Value) bool {
	f, _ := constant.Float64Val(x)
	return !math.IsInf(f, 0)
}

func roundFloat64(x constant.Value) constant.Value {
	f, _ := constant.Float64Val(x)
	if !math.IsInf(f, 0) {
		return constant.MakeFloat64(f)
	}
	return nil
}

// representable checks that a constant operand is representable in the given

	case constant.Float:
		i := constant.ToInt(x)
		if i.Kind() != constant.Int {
			v, _ := constant.Float64Val(x)
			return v
		}
		x = i
		fallthrough
	case constant.Int:
		if v, ok := constant.Int64Val(x); ok {
			return v
		}
		if v, ok := constant.Uint64Val(x); ok {
			return v
		}
	case constant.String:
		return constant.StringVal(x)
	case constant.Bool: