}
			if val != nil {
				*val = constant.MakeString(string(codepoint))
			}
			return true
		}
		return false
	}

	var ok bool
	var cause string
	switch {
	case constArg && isConstType(T):
		// constant conversion
		ok = constConvertibleTo(T, &x.val)
		// A conversion from an integer constant to an integer type
		// can only fail if there's overflow. Give a concise error.
		// (go.dev/issue/63563)

			}
			if val != nil {
				*val = constant.MakeString(string(codepoint))
			}
			return true
		}
		return false
	}

	var ok bool
	var cause string
	switch {
	case constArg && isConstType(T):
		// constant conversion
		ok = constConvertibleTo(T, &x.val)
		// A conversion from an integer constant to an integer type
		// can only fail if there's overflow. Give a concise error.
		// (go.dev/issue/63563)

	if rhs, ok := want.(*types.Basic); ok && rhs.Info()&types.IsUntyped > 0 {
		if lhs, ok := got.Underlying().(*types.Basic); ok {
			return rhs.Info()&types.IsConstType == lhs.Info()&types.IsConstType
		}
	}
	return types.AssignableTo(want, got)
}

// MakeReadFile returns a simple implementation of the Pass.ReadFile function.

func isString(t Type) bool         { return isBasic(t, IsString) }
func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
func isConstType(t Type) bool      { return isBasic(t, IsConstType) }

// isBasic reports whether under(t) is a basic type with the specified info.
// If t is a type parameter the result is false; i.e.,
// isBasic does not look inside a type parameter.

func isString(t Type) bool         { return isBasic(t, IsString) }
func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
func isConstType(t Type) bool      { return isBasic(t, IsConstType) }

// isBasic reports whether under(t) is a basic type with the specified info.
// If t is a type parameter the result is false; i.e.,
// isBasic does not look inside a type parameter.

	assert(typ != nil)
	if mode == invalid {
		return // omit
	}
	if mode == constant_ {
		assert(val != nil)
		// We check allBasic(typ, IsConstType) here as constant expressions may be
		// recorded as type parameters.
		assert(!isValid(typ) || allBasic(typ, IsConstType))
	}
	if m := check.Types; m != nil {
		m[x] = TypeAndValue{mode, typ, val}
	}
}

	assert(typ != nil)
	if mode == invalid {
		return // omit
	}
	if mode == constant_ {
		assert(val != nil)
		// We check allBasic(typ, IsConstType) here as constant expressions may be
		// recorded as type parameters.
		assert(!isValid(typ) || allBasic(typ, IsConstType))
	}
	if m := check.Types; m != nil {
		m[x] = TypeAndValue{mode, typ, val}
	}
	if check.StoreTypesInSyntax {
		tv := TypeAndValue{mode, typ, val}

	typ = r.typ()
	if r.p.exportVersion >= iexportVersionGo1_18 {
		// TODO: add support for using the kind
		_ = constant.Kind(r.int64())
	}

	switch b := typ.Underlying().(*types.Basic); b.Info() & types.IsConstType {
	case types.IsBoolean:
		val = constant.MakeBool(r.bool())

	case types.IsString:
		val = constant.MakeString(r.string())

	case types.IsInteger:
		var x big.Int
		r.mpint(&x, b)

	check.errpos = nopos

	// provide valid constant value under all circumstances
	obj.val = constant.MakeUnknown()

	// determine type, if any
	if typ != nil {
		t := check.typ(typ)
		if !isConstType(t) {
			// don't report an error if the type is an invalid C (defined) type
			// (go.dev/issue/22090)
			if isValid(under(t)) {
				check.errorf(typ, InvalidConstType, "invalid constant type %s", t)
			}

	check.errpos = nil

	// provide valid constant value under all circumstances
	obj.val = constant.MakeUnknown()

	// determine type, if any
	if typ != nil {
		t := check.typ(typ)
		if !isConstType(t) {
			// don't report an error if the type is an invalid C (defined) type
			// (go.dev/issue/22090)
			if isValid(under(t)) {
				check.errorf(typ, InvalidConstType, "invalid constant type %s", t)
			}