//
// commaok    <expr> (<untyped kind> <mode>                    )
// commaok    <expr> (               <mode>       of type <typ>)
//
// commaerr   <expr> (<untyped kind> <mode>                    )
// commaerr   <expr> (               <mode>       of type <typ>)
//
// cgofunc    <expr> (<untyped kind> <mode>                    )
// cgofunc    <expr> (               <mode>       of type <typ>)

//
// commaok    <expr> (<untyped kind> <mode>                    )
// commaok    <expr> (               <mode>       of type <typ>)
//
// commaerr   <expr> (<untyped kind> <mode>                    )
// commaerr   <expr> (               <mode>       of type <typ>)
//
// cgofunc    <expr> (<untyped kind> <mode>                    )
// cgofunc    <expr> (               <mode>       of type <typ>)

// Builtins are not considered values. Constant values have a non-
// nil Value.
func (tv TypeAndValue) IsValue() bool {
	switch tv.mode {
	case constant_, variable, mapindex, value, commaok, commaerr:
		return true
	}
	return false
}

// IsNil reports whether the corresponding expression denotes the
// predeclared value nil.
func (tv TypeAndValue) IsNil() bool {

// Builtins are not considered values. Constant values have a non-
// nil Value.
func (tv TypeAndValue) IsValue() bool {
	switch tv.mode {
	case constant_, variable, mapindex, value, nilvalue, commaok, commaerr:
		return true
	}
	return false
}

// IsNil reports whether the corresponding expression denotes the
// predeclared value nil. Depending on context, it may have been

	check.singleValue(x)

	switch x.mode {
	case invalid:
		return // error reported before
	case nilvalue:
		assert(isTypes2)
		// ok
	case constant_, variable, mapindex, value, commaok, commaerr:
		// ok
	default:
		// we may get here because of other problems (go.dev/issue/39634, crash 12)
		// TODO(gri) do we need a new "generic" error code here?

	check.singleValue(x)

	switch x.mode {
	case invalid:
		return // error reported before
	case nilvalue:
		assert(isTypes2)
		// ok
	case constant_, variable, mapindex, value, commaok, commaerr:
		// ok
	default:
		// we may get here because of other problems (go.dev/issue/39634, crash 12)
		// TODO(gri) do we need a new "generic" error code here?

		return
	}

	// exactly one (possibly invalid or comma-ok) value
	list = []*operand{&x}
	if allowCommaOk && (x.mode == mapindex || x.mode == commaok || x.mode == commaerr) {
		x2 := &operand{mode: value, expr: e, typ: Typ[UntypedBool]}
		if x.mode == commaerr {
			x2.typ = universeError
		}
		list = append(list, x2)
		commaOk = true
	}

	return
}

		return
	}

	// exactly one (possibly invalid or comma-ok) value
	list = []*operand{&x}
	if allowCommaOk && (x.mode == mapindex || x.mode == commaok || x.mode == commaerr) {
		x2 := &operand{mode: value, expr: e, typ: Typ[UntypedBool]}
		if x.mode == commaerr {
			x2.typ = universeError
		}
		list = append(list, x2)
		commaOk = true
	}

	return
}

		check.recordTypeAndValue(call.Fun, value, sig, nil)
	}

	// determine result
	switch sig.results.Len() {
	case 0:
		x.mode = novalue
	case 1:
		if cgocall {
			x.mode = commaerr
		} else {
			x.mode = value
		}
		x.typ = sig.results.vars[0].typ // unpack tuple
	default:
		x.mode = value
		x.typ = sig.results
	}
	x.expr = call
	check.hasCallOrRecv = true

		check.recordTypeAndValue(call.Fun, value, sig, nil)
	}

	// determine result
	switch sig.results.Len() {
	case 0:
		x.mode = novalue
	case 1:
		if cgocall {
			x.mode = commaerr
		} else {
			x.mode = value
		}
		x.typ = sig.results.vars[0].typ // unpack tuple
	default:
		x.mode = value
		x.typ = sig.results
	}
	x.expr = call
	check.hasCallOrRecv = true