/
typecheck.go
1283 lines (1158 loc) · 32.6 KB
/
typecheck.go
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package interp
import (
"errors"
"go/constant"
"go/token"
"math"
"reflect"
)
type opPredicates map[action]func(reflect.Type) bool
// typecheck handles all type checking following "go/types" logic.
//
// Due to variant type systems (itype vs reflect.Type) a single
// type system should used, namely reflect.Type with exception
// of the untyped flag on itype.
type typecheck struct {
scope *scope
}
// op type checks an expression against a set of expression predicates.
func (check typecheck) op(p opPredicates, a action, n, c *node, t reflect.Type) error {
if pred := p[a]; pred != nil {
if !pred(t) {
return n.cfgErrorf("invalid operation: operator %v not defined on %s", n.action, c.typ.id())
}
} else {
return n.cfgErrorf("invalid operation: unknown operator %v", n.action)
}
return nil
}
// assignment checks if n can be assigned to typ.
//
// Use typ == nil to indicate assignment to an untyped blank identifier.
func (check typecheck) assignment(n *node, typ *itype, context string) error {
if n.typ == nil {
return n.cfgErrorf("invalid type in %s", context)
}
if n.typ.untyped {
if typ == nil || isInterface(typ) {
if typ == nil && n.typ.cat == nilT {
return n.cfgErrorf("use of untyped nil in %s", context)
}
typ = n.typ.defaultType(n.rval, check.scope)
}
if err := check.convertUntyped(n, typ); err != nil {
return err
}
}
if typ == nil {
return nil
}
if !n.typ.assignableTo(typ) && typ.str != "*unsafe2.dummy" {
if context == "" {
return n.cfgErrorf("cannot use type %s as type %s", n.typ.id(), typ.id())
}
return n.cfgErrorf("cannot use type %s as type %s in %s", n.typ.id(), typ.id(), context)
}
return nil
}
// assignExpr type checks an assign expression.
//
// This is done per pair of assignments.
func (check typecheck) assignExpr(n, dest, src *node) error {
if n.action == aAssign {
isConst := n.anc.kind == constDecl
if !isConst {
// var operations must be typed
dest.typ = dest.typ.defaultType(src.rval, check.scope)
}
return check.assignment(src, dest.typ, "assignment")
}
// assignment operations.
if n.nleft > 1 || n.nright > 1 {
return n.cfgErrorf("assignment operation %s requires single-valued expressions", n.action)
}
return check.binaryExpr(n)
}
// addressExpr type checks a unary address expression.
func (check typecheck) addressExpr(n *node) error {
c0 := n.child[0]
found := false
for !found {
switch c0.kind {
case parenExpr:
c0 = c0.child[0]
continue
case selectorExpr:
c0 = c0.child[1]
continue
case starExpr:
c0 = c0.child[0]
continue
case indexExpr, sliceExpr:
c := c0.child[0]
if isArray(c.typ) || isMap(c.typ) {
c0 = c
found = true
continue
}
case compositeLitExpr, identExpr:
found = true
continue
}
return n.cfgErrorf("invalid operation: cannot take address of %s [kind: %s]", c0.typ.id(), kinds[c0.kind])
}
return nil
}
// starExpr type checks a star expression on a variable.
func (check typecheck) starExpr(n *node) error {
if n.typ.TypeOf().Kind() != reflect.Ptr {
return n.cfgErrorf("invalid operation: cannot indirect %q", n.name())
}
return nil
}
var unaryOpPredicates = opPredicates{
aInc: isNumber,
aDec: isNumber,
aPos: isNumber,
aNeg: isNumber,
aBitNot: isInt,
aNot: isBoolean,
}
// unaryExpr type checks a unary expression.
func (check typecheck) unaryExpr(n *node) error {
c0 := n.child[0]
if isBlank(c0) {
return n.cfgErrorf("cannot use _ as value")
}
t0 := c0.typ.TypeOf()
if n.action == aRecv {
if !isChan(c0.typ) {
return n.cfgErrorf("invalid operation: cannot receive from non-channel %s", c0.typ.id())
}
if isSendChan(c0.typ) {
return n.cfgErrorf("invalid operation: cannot receive from send-only channel %s", c0.typ.id())
}
return nil
}
return check.op(unaryOpPredicates, n.action, n, c0, t0)
}
// shift type checks a shift binary expression.
func (check typecheck) shift(n *node) error {
c0, c1 := n.child[0], n.child[1]
t0, t1 := c0.typ.TypeOf(), c1.typ.TypeOf()
var v0 constant.Value
if c0.typ.untyped && c0.rval.IsValid() {
v0 = constant.ToInt(c0.rval.Interface().(constant.Value))
c0.rval = reflect.ValueOf(v0)
}
if !(c0.typ.untyped && v0 != nil && v0.Kind() == constant.Int || isInt(t0)) {
return n.cfgErrorf("invalid operation: shift of type %v", c0.typ.id())
}
switch {
case c1.typ.untyped:
if err := check.convertUntyped(c1, check.scope.getType("uint")); err != nil {
return n.cfgErrorf("invalid operation: shift count type %v, must be integer", c1.typ.id())
}
case isInt(t1):
// nothing to do
default:
return n.cfgErrorf("invalid operation: shift count type %v, must be integer", c1.typ.id())
}
return nil
}
// comparison type checks a comparison binary expression.
func (check typecheck) comparison(n *node) error {
t0, t1 := n.child[0].typ, n.child[1].typ
if !t0.assignableTo(t1) && !t1.assignableTo(t0) {
return n.cfgErrorf("invalid operation: mismatched types %s and %s", t0.id(), t1.id())
}
ok := false
if !isInterface(t0) && !isInterface(t1) && !t0.isNil() && !t1.isNil() && t0.untyped == t1.untyped && t0.id() != t1.id() && !typeDefined(t0, t1) {
// Non interface types must be really equals.
return n.cfgErrorf("invalid operation: mismatched types %s and %s", t0.id(), t1.id())
}
switch n.action {
case aEqual, aNotEqual:
ok = t0.comparable() && t1.comparable() || t0.isNil() && t1.hasNil() || t1.isNil() && t0.hasNil()
case aLower, aLowerEqual, aGreater, aGreaterEqual:
ok = t0.ordered() && t1.ordered()
}
if !ok {
typ := t0
if typ.isNil() {
typ = t1
}
return n.cfgErrorf("invalid operation: operator %v not defined on %s", n.action, typ.id())
}
return nil
}
var binaryOpPredicates = opPredicates{
aAdd: func(typ reflect.Type) bool { return isNumber(typ) || isString(typ) },
aSub: isNumber,
aMul: isNumber,
aQuo: isNumber,
aRem: isInt,
aAnd: isInt,
aOr: isInt,
aXor: isInt,
aAndNot: isInt,
aLand: isBoolean,
aLor: isBoolean,
}
// binaryExpr type checks a binary expression.
func (check typecheck) binaryExpr(n *node) error {
c0, c1 := n.child[0], n.child[1]
if isBlank(c0) || isBlank(c1) {
return n.cfgErrorf("cannot use _ as value")
}
a := n.action
if isAssignAction(a) {
a--
}
if isShiftAction(a) {
return check.shift(n)
}
switch n.action {
case aAdd:
if n.typ == nil {
break
}
// Catch mixing string and number for "+" operator use.
k, k0, k1 := isNumber(n.typ.TypeOf()), isNumber(c0.typ.TypeOf()), isNumber(c1.typ.TypeOf())
if k != k0 || k != k1 {
return n.cfgErrorf("cannot use type %s as type %s in assignment", c0.typ.id(), n.typ.id())
}
case aRem:
if zeroConst(c1) {
return n.cfgErrorf("invalid operation: division by zero")
}
case aQuo:
if zeroConst(c1) {
return n.cfgErrorf("invalid operation: division by zero")
}
if c0.rval.IsValid() && c1.rval.IsValid() {
// Avoid constant conversions below to ensure correct constant integer quotient.
return nil
}
}
_ = check.convertUntyped(c0, c1.typ)
_ = check.convertUntyped(c1, c0.typ)
if isComparisonAction(a) {
return check.comparison(n)
}
if !c0.typ.equals(c1.typ) {
return n.cfgErrorf("invalid operation: mismatched types %s and %s", c0.typ.id(), c1.typ.id())
}
t0 := c0.typ.TypeOf()
return check.op(binaryOpPredicates, a, n, c0, t0)
}
func zeroConst(n *node) bool {
return n.typ.untyped && constant.Sign(n.rval.Interface().(constant.Value)) == 0
}
func (check typecheck) index(n *node, max int) error {
if err := check.convertUntyped(n, check.scope.getType("int")); err != nil {
return err
}
if !isInt(n.typ.TypeOf()) {
return n.cfgErrorf("index %s must be integer", n.typ.id())
}
if !n.rval.IsValid() || max < 1 {
return nil
}
if int(vInt(n.rval)) >= max {
return n.cfgErrorf("index %s is out of bounds", n.typ.id())
}
return nil
}
// arrayLitExpr type checks an array composite literal expression.
func (check typecheck) arrayLitExpr(child []*node, typ *itype) error {
cat := typ.cat
length := typ.length
typ = typ.val
visited := make(map[int]bool, len(child))
index := 0
for _, c := range child {
n := c
switch {
case c.kind == keyValueExpr:
if err := check.index(c.child[0], length); err != nil {
return c.cfgErrorf("index %s must be integer constant", c.child[0].typ.id())
}
n = c.child[1]
index = int(vInt(c.child[0].rval))
case cat == arrayT && index >= length:
return c.cfgErrorf("index %d is out of bounds (>= %d)", index, length)
}
if visited[index] {
return n.cfgErrorf("duplicate index %d in array or slice literal", index)
}
visited[index] = true
index++
if err := check.assignment(n, typ, "array or slice literal"); err != nil {
return err
}
}
return nil
}
// mapLitExpr type checks an map composite literal expression.
func (check typecheck) mapLitExpr(child []*node, ktyp, vtyp *itype) error {
visited := make(map[interface{}]bool, len(child))
for _, c := range child {
if c.kind != keyValueExpr {
return c.cfgErrorf("missing key in map literal")
}
key, val := c.child[0], c.child[1]
if err := check.assignment(key, ktyp, "map literal"); err != nil {
return err
}
if key.rval.IsValid() {
kval := key.rval.Interface()
if visited[kval] {
return c.cfgErrorf("duplicate key %s in map literal", kval)
}
visited[kval] = true
}
if err := check.assignment(val, vtyp, "map literal"); err != nil {
return err
}
}
return nil
}
// structLitExpr type checks a struct composite literal expression.
func (check typecheck) structLitExpr(child []*node, typ *itype) error {
if len(child) == 0 {
return nil
}
if child[0].kind == keyValueExpr {
// All children must be keyValueExpr
visited := make([]bool, len(typ.field))
for _, c := range child {
if c.kind != keyValueExpr {
return c.cfgErrorf("mixture of field:value and value elements in struct literal")
}
key, val := c.child[0], c.child[1]
name := key.ident
if name == "" {
return c.cfgErrorf("invalid field name %s in struct literal", key.typ.id())
}
i := typ.fieldIndex(name)
if i < 0 {
return c.cfgErrorf("unknown field %s in struct literal", name)
}
field := typ.field[i]
if err := check.assignment(val, field.typ, "struct literal"); err != nil {
return err
}
if visited[i] {
return c.cfgErrorf("duplicate field name %s in struct literal", name)
}
visited[i] = true
}
return nil
}
// No children can be keyValueExpr
for i, c := range child {
if c.kind == keyValueExpr {
return c.cfgErrorf("mixture of field:value and value elements in struct literal")
}
if i >= len(typ.field) {
return c.cfgErrorf("too many values in struct literal")
}
field := typ.field[i]
// TODO(nick): check if this field is not exported and in a different package.
if err := check.assignment(c, field.typ, "struct literal"); err != nil {
return err
}
}
if len(child) < len(typ.field) {
return child[len(child)-1].cfgErrorf("too few values in struct literal")
}
return nil
}
// structBinLitExpr type checks a struct composite literal expression on a binary type.
func (check typecheck) structBinLitExpr(child []*node, typ reflect.Type) error {
if len(child) == 0 {
return nil
}
if child[0].kind == keyValueExpr {
// All children must be keyValueExpr
visited := make(map[string]bool, typ.NumField())
for _, c := range child {
if c.kind != keyValueExpr {
return c.cfgErrorf("mixture of field:value and value elements in struct literal")
}
key, val := c.child[0], c.child[1]
name := key.ident
if name == "" {
return c.cfgErrorf("invalid field name %s in struct literal", key.typ.id())
}
field, ok := typ.FieldByName(name)
if !ok {
return c.cfgErrorf("unknown field %s in struct literal", name)
}
if err := check.assignment(val, valueTOf(field.Type), "struct literal"); err != nil {
return err
}
if visited[field.Name] {
return c.cfgErrorf("duplicate field name %s in struct literal", name)
}
visited[field.Name] = true
}
return nil
}
// No children can be keyValueExpr
for i, c := range child {
if c.kind == keyValueExpr {
return c.cfgErrorf("mixture of field:value and value elements in struct literal")
}
if i >= typ.NumField() {
return c.cfgErrorf("too many values in struct literal")
}
field := typ.Field(i)
if !canExport(field.Name) {
return c.cfgErrorf("implicit assignment to unexported field %s in %s literal", field.Name, typ)
}
if err := check.assignment(c, valueTOf(field.Type), "struct literal"); err != nil {
return err
}
}
if len(child) < typ.NumField() {
return child[len(child)-1].cfgErrorf("too few values in struct literal")
}
return nil
}
// sliceExpr type checks a slice expression.
func (check typecheck) sliceExpr(n *node) error {
for _, c := range n.child {
if isBlank(c) {
return n.cfgErrorf("cannot use _ as value")
}
}
c, child := n.child[0], n.child[1:]
t := c.typ.TypeOf()
var low, high, max *node
if len(child) >= 1 {
if n.action == aSlice {
low = child[0]
} else {
high = child[0]
}
}
if len(child) >= 2 {
if n.action == aSlice {
high = child[1]
} else {
max = child[1]
}
}
if len(child) == 3 && n.action == aSlice {
max = child[2]
}
l := -1
valid := false
switch t.Kind() {
case reflect.String:
valid = true
if c.rval.IsValid() {
l = len(vString(c.rval))
}
if max != nil {
return max.cfgErrorf("invalid operation: 3-index slice of string")
}
case reflect.Array:
valid = true
l = t.Len()
// TODO(marc): check addressable status of array object (i.e. composite arrays are not).
case reflect.Slice:
valid = true
case reflect.Ptr:
if t.Elem().Kind() == reflect.Array {
valid = true
l = t.Elem().Len()
}
}
if !valid {
return c.cfgErrorf("cannot slice type %s", c.typ.id())
}
var ind [3]int64
for i, nod := range []*node{low, high, max} {
x := int64(-1)
switch {
case nod != nil:
max := -1
if l >= 0 {
max = l + 1
}
if err := check.index(nod, max); err != nil {
return err
}
if nod.rval.IsValid() {
x = vInt(nod.rval)
}
case i == 0:
x = 0
case l >= 0:
x = int64(l)
}
ind[i] = x
}
for i, x := range ind[:len(ind)-1] {
if x <= 0 {
continue
}
for _, y := range ind[i+1:] {
if y < 0 || x <= y {
continue
}
return n.cfgErrorf("invalid index values, must be low <= high <= max")
}
}
return nil
}
// typeAssertionExpr type checks a type assert expression.
func (check typecheck) typeAssertionExpr(n *node, typ *itype) error {
// TODO(nick): This type check is not complete and should be revisited once
// https://github.com/golang/go/issues/39717 lands. It is currently impractical to
// type check Named types as they cannot be asserted.
if rt := n.typ.TypeOf(); rt.Kind() != reflect.Interface && rt != valueInterfaceType {
return n.cfgErrorf("invalid type assertion: non-interface type %s on left", n.typ.id())
}
ims := n.typ.methods()
if len(ims) == 0 {
// Empty interface must be a dynamic check.
return nil
}
if isInterface(typ) {
// Asserting to an interface is a dynamic check as we must look to the
// underlying struct.
return nil
}
for name := range ims {
im := lookupFieldOrMethod(n.typ, name)
tm := lookupFieldOrMethod(typ, name)
if im == nil {
// This should not be possible.
continue
}
if tm == nil {
// Lookup for non-exported methods is impossible
// for bin types, ignore them as they can't be used
// directly by the interpreted programs.
if !token.IsExported(name) && isBin(typ) {
continue
}
return n.cfgErrorf("impossible type assertion: %s does not implement %s (missing %v method)", typ.id(), n.typ.id(), name)
}
if tm.recv != nil && tm.recv.TypeOf().Kind() == reflect.Ptr && typ.TypeOf().Kind() != reflect.Ptr {
return n.cfgErrorf("impossible type assertion: %s does not implement %s as %q method has a pointer receiver", typ.id(), n.typ.id(), name)
}
if im.cat != funcT || tm.cat != funcT {
// It only makes sense to compare in/out parameter types if both types are functions.
continue
}
err := n.cfgErrorf("impossible type assertion: %s does not implement %s", typ.id(), n.typ.id())
if im.numIn() != tm.numIn() || im.numOut() != tm.numOut() {
return err
}
for i := 0; i < im.numIn(); i++ {
if !im.in(i).equals(tm.in(i)) {
return err
}
}
for i := 0; i < im.numOut(); i++ {
if !im.out(i).equals(tm.out(i)) {
return err
}
}
}
return nil
}
// conversion type checks the conversion of n to typ.
func (check typecheck) conversion(n *node, typ *itype) error {
var c constant.Value
if n.rval.IsValid() {
if con, ok := n.rval.Interface().(constant.Value); ok {
c = con
}
}
var ok bool
switch {
case c != nil && isConstType(typ):
switch t := typ.TypeOf(); {
case representableConst(c, t):
ok = true
case isInt(n.typ.TypeOf()) && isString(t):
codepoint := int64(-1)
if i, ok := constant.Int64Val(c); ok {
codepoint = i
}
n.rval = reflect.ValueOf(constant.MakeString(string(rune(codepoint))))
ok = true
}
case n.typ.convertibleTo(typ):
ok = true
}
if !ok {
return n.cfgErrorf("cannot convert expression of type %s to type %s", n.typ.id(), typ.id())
}
if !n.typ.untyped || c == nil {
return nil
}
if isInterface(typ) || !isConstType(typ) {
typ = n.typ.defaultType(n.rval, check.scope)
}
return check.convertUntyped(n, typ)
}
type param struct {
nod *node
typ *itype
}
func (p param) Type() *itype {
if p.typ != nil {
return p.typ
}
return p.nod.typ
}
// unpackParams unpacks child parameters into a slice of param.
// If there is only 1 child and it is a callExpr with an n-value return,
// the return types are returned, otherwise the original child nodes are
// returned with nil typ.
func (check typecheck) unpackParams(child []*node) (params []param) {
if len(child) == 1 && isCall(child[0]) && child[0].child[0].typ.numOut() > 1 {
c0 := child[0]
ftyp := child[0].child[0].typ
for i := 0; i < ftyp.numOut(); i++ {
params = append(params, param{nod: c0, typ: ftyp.out(i)})
}
return params
}
for _, c := range child {
params = append(params, param{nod: c})
}
return params
}
var builtinFuncs = map[string]struct {
args int
variadic bool
}{
bltnAlignof: {args: 1, variadic: false},
bltnAppend: {args: 1, variadic: true},
bltnCap: {args: 1, variadic: false},
bltnClose: {args: 1, variadic: false},
bltnComplex: {args: 2, variadic: false},
bltnImag: {args: 1, variadic: false},
bltnCopy: {args: 2, variadic: false},
bltnDelete: {args: 2, variadic: false},
bltnLen: {args: 1, variadic: false},
bltnMake: {args: 1, variadic: true},
bltnNew: {args: 1, variadic: false},
bltnOffsetof: {args: 1, variadic: false},
bltnPanic: {args: 1, variadic: false},
bltnPrint: {args: 0, variadic: true},
bltnPrintln: {args: 0, variadic: true},
bltnReal: {args: 1, variadic: false},
bltnRecover: {args: 0, variadic: false},
bltnSizeof: {args: 1, variadic: false},
}
func (check typecheck) builtin(name string, n *node, child []*node, ellipsis bool) error {
fun := builtinFuncs[name]
if ellipsis && name != bltnAppend {
return n.cfgErrorf("invalid use of ... with builtin %s", name)
}
var params []param
nparams := len(child)
switch name {
case bltnMake, bltnNew:
// Special param handling
default:
params = check.unpackParams(child)
nparams = len(params)
}
if nparams < fun.args {
return n.cfgErrorf("not enough arguments in call to %s", name)
} else if !fun.variadic && nparams > fun.args {
return n.cfgErrorf("too many arguments for %s", name)
}
switch name {
case bltnAppend:
typ := params[0].Type()
t := typ.TypeOf()
if t == nil || t.Kind() != reflect.Slice {
return params[0].nod.cfgErrorf("first argument to append must be slice; have %s", typ.id())
}
if nparams == 1 {
return nil
}
// Special case append([]byte, "test"...) is allowed.
t1 := params[1].Type()
if nparams == 2 && ellipsis && t.Elem().Kind() == reflect.Uint8 && t1.TypeOf().Kind() == reflect.String {
if t1.untyped {
return check.convertUntyped(params[1].nod, check.scope.getType("string"))
}
return nil
}
fun := &node{
typ: &itype{
cat: funcT,
arg: []*itype{
typ,
{cat: variadicT, val: valueTOf(t.Elem())},
},
ret: []*itype{typ},
},
ident: "append",
}
return check.arguments(n, child, fun, ellipsis)
case bltnCap, bltnLen:
typ := arrayDeref(params[0].Type())
ok := false
switch typ.TypeOf().Kind() {
case reflect.Array, reflect.Slice, reflect.Chan:
ok = true
case reflect.String, reflect.Map:
ok = name == bltnLen
}
if !ok {
return params[0].nod.cfgErrorf("invalid argument for %s", name)
}
case bltnClose:
p := params[0]
typ := p.Type()
t := typ.TypeOf()
if t.Kind() != reflect.Chan {
return p.nod.cfgErrorf("invalid operation: non-chan type %s", p.nod.typ.id())
}
if t.ChanDir() == reflect.RecvDir {
return p.nod.cfgErrorf("invalid operation: cannot close receive-only channel")
}
case bltnComplex:
var err error
p0, p1 := params[0], params[1]
typ0, typ1 := p0.Type(), p1.Type()
switch {
case typ0.untyped && !typ1.untyped:
err = check.convertUntyped(p0.nod, typ1)
case !typ0.untyped && typ1.untyped:
err = check.convertUntyped(p1.nod, typ0)
case typ0.untyped && typ1.untyped:
fltType := untypedFloat(nil)
err = check.convertUntyped(p0.nod, fltType)
if err != nil {
break
}
err = check.convertUntyped(p1.nod, fltType)
}
if err != nil {
return err
}
// check we have the correct types after conversion.
typ0, typ1 = p0.Type(), p1.Type()
if !typ0.equals(typ1) {
return n.cfgErrorf("invalid operation: mismatched types %s and %s", typ0.id(), typ1.id())
}
if !isFloat(typ0.TypeOf()) {
return n.cfgErrorf("invalid operation: arguments have type %s, expected floating-point", typ0.id())
}
case bltnImag, bltnReal:
p := params[0]
typ := p.Type()
if typ.untyped {
if err := check.convertUntyped(p.nod, untypedComplex(nil)); err != nil {
return err
}
}
typ = p.Type()
if !isComplex(typ.TypeOf()) {
return p.nod.cfgErrorf("invalid argument type %s for %s", typ.id(), name)
}
case bltnCopy:
typ0, typ1 := params[0].Type(), params[1].Type()
var t0, t1 reflect.Type
if t := typ0.TypeOf(); t.Kind() == reflect.Slice {
t0 = t.Elem()
}
switch t := typ1.TypeOf(); t.Kind() {
case reflect.String:
t1 = reflect.TypeOf(byte(1))
case reflect.Slice:
t1 = t.Elem()
}
if t0 == nil || t1 == nil {
return n.cfgErrorf("copy expects slice arguments")
}
if !reflect.DeepEqual(t0, t1) {
return n.cfgErrorf("arguments to copy have different element types %s and %s", typ0.id(), typ1.id())
}
case bltnDelete:
typ := params[0].Type()
if typ.TypeOf().Kind() != reflect.Map {
return params[0].nod.cfgErrorf("first argument to delete must be map; have %s", typ.id())
}
ktyp := params[1].Type()
if typ.key != nil && !ktyp.assignableTo(typ.key) {
return params[1].nod.cfgErrorf("cannot use %s as type %s in delete", ktyp.id(), typ.key.id())
}
case bltnMake:
var min int
switch child[0].typ.TypeOf().Kind() {
case reflect.Slice:
min = 2
case reflect.Map, reflect.Chan:
min = 1
default:
return child[0].cfgErrorf("cannot make %s; type must be slice, map, or channel", child[0].typ.id())
}
if nparams < min {
return n.cfgErrorf("not enough arguments in call to make")
} else if nparams > min+1 {
return n.cfgErrorf("too many arguments for make")
}
var sizes []int
for _, c := range child[1:] {
if err := check.index(c, -1); err != nil {
return err
}
if c.rval.IsValid() {
sizes = append(sizes, int(vInt(c.rval)))
}
}
for len(sizes) == 2 && sizes[0] > sizes[1] {
return n.cfgErrorf("len larger than cap in make")
}
case bltnPanic:
return check.assignment(params[0].nod, check.scope.getType("interface{}"), "argument to panic")
case bltnPrint, bltnPrintln:
for _, param := range params {
if param.typ != nil {
continue
}
if err := check.assignment(param.nod, nil, "argument to "+name); err != nil {
return err
}
}
case bltnRecover, bltnNew, bltnAlignof, bltnOffsetof, bltnSizeof:
// Nothing to do.
default:
return n.cfgErrorf("unsupported builtin %s", name)
}
return nil
}
// arrayDeref returns A if typ is *A, otherwise typ.
func arrayDeref(typ *itype) *itype {
if typ.cat == valueT && typ.TypeOf().Kind() == reflect.Ptr {
t := typ.TypeOf()
if t.Elem().Kind() == reflect.Array {
return valueTOf(t.Elem())
}
return typ
}
if typ.cat == ptrT && typ.val.cat == arrayT {
return typ.val
}
return typ
}
// arguments type checks the call expression arguments.
func (check typecheck) arguments(n *node, child []*node, fun *node, ellipsis bool) error {
params := check.unpackParams(child)
l := len(child)
if ellipsis {
if !fun.typ.isVariadic() {
return n.cfgErrorf("invalid use of ..., corresponding parameter is non-variadic")
}
if len(params) > l {
return child[0].cfgErrorf("cannot use ... with %d-valued %s", child[0].child[0].typ.numOut(), child[0].child[0].typ.id())
}
}
var cnt int
for i, param := range params {
ellip := i == l-1 && ellipsis
if err := check.argument(param, fun.typ, cnt, l, ellip); err != nil {
return err
}
cnt++
}
if fun.typ.isVariadic() {
cnt++
}
if cnt < fun.typ.numIn() {
return n.cfgErrorf("not enough arguments in call to %s", fun.name())
}
return nil
}
func (check typecheck) argument(p param, ftyp *itype, i, l int, ellipsis bool) error {
atyp := getArg(ftyp, i)
if atyp == nil {
return p.nod.cfgErrorf("too many arguments")
}
if p.typ == nil && isCall(p.nod) && p.nod.child[0].typ.numOut() != 1 {
if l == 1 {
return p.nod.cfgErrorf("cannot use %s as type %s", p.nod.child[0].typ.id(), getArgsID(ftyp))
}
return p.nod.cfgErrorf("cannot use %s as type %s", p.nod.child[0].typ.id(), atyp.id())
}