// typeAssert checks whether dynamic type of itf is instr.AssertedType.
// It returns the extracted value on success, and panics on failure,
// unless instr.CommaOk, in which case it always returns a "value,ok" tuple.
//
func typeAssert(i *interpreter, instr *ssa.TypeAssert, itf iface) value {
var v value
err := ""
if itf.t == nil {
err = fmt.Sprintf("interface conversion: interface is nil, not %s", instr.AssertedType)
} else if idst, ok := instr.AssertedType.Underlying().(*types.Interface); ok {
v = itf
err = checkInterface(i, idst, itf)
} else if types.Identical(itf.t, instr.AssertedType) {
v = copyVal(itf.v) // extract value
} else {
err = fmt.Sprintf("interface conversion: interface is %s, not %s", itf.t, instr.AssertedType)
}
if err != "" {
if !instr.CommaOk {
panic(err)
}
return tuple{zero(instr.AssertedType), false}
}
if instr.CommaOk {
return tuple{v, true}
}
return v
}
// Set sets the map entry for key to val,
// and returns the previous entry, if any.
func (m *Map) Set(key types.Type, value interface{}) (prev interface{}) {
if m.table != nil {
hash := m.hasher.Hash(key)
bucket := m.table[hash]
var hole *entry
for i, e := range bucket {
if e.key == nil {
hole = &bucket[i]
} else if types.Identical(key, e.key) {
prev = e.value
bucket[i].value = value
return
}
}
if hole != nil {
*hole = entry{key, value} // overwrite deleted entry
} else {
m.table[hash] = append(bucket, entry{key, value})
}
} else {
if m.hasher.memo == nil {
m.hasher = MakeHasher()
}
hash := m.hasher.Hash(key)
m.table = map[uint32][]entry{hash: {entry{key, value}}}
}
m.length++
return
}
// computeTrackBits sets a.track to the necessary 'track' bits for the pointer queries.
func (a *analysis) computeTrackBits() {
var queryTypes []types.Type
for v := range a.config.Queries {
queryTypes = append(queryTypes, v.Type())
}
for v := range a.config.IndirectQueries {
queryTypes = append(queryTypes, mustDeref(v.Type()))
}
for _, t := range queryTypes {
switch t.Underlying().(type) {
case *types.Chan:
a.track |= trackChan
case *types.Map:
a.track |= trackMap
case *types.Pointer:
a.track |= trackPtr
case *types.Slice:
a.track |= trackSlice
case *types.Interface:
a.track = trackAll
return
}
if rVObj := a.reflectValueObj; rVObj != nil && types.Identical(t, rVObj.Type()) {
a.track = trackAll
return
}
}
}
// containsAllIdsOf reports whether the method identifiers of T are a
// superset of those in U. If U belongs to an interface type, the
// result is equal to types.Assignable(T, U), but is cheaper to compute.
//
// TODO(gri): make this a method of *types.MethodSet.
//
func containsAllIdsOf(T, U *types.MethodSet) bool {
t, tlen := 0, T.Len()
u, ulen := 0, U.Len()
for t < tlen && u < ulen {
tMeth := T.At(t).Obj()
uMeth := U.At(u).Obj()
tId := tMeth.Id()
uId := uMeth.Id()
if tId > uId {
// U has a method T lacks: fail.
return false
}
if tId < uId {
// T has a method U lacks: ignore it.
t++
continue
}
// U and T both have a method of this Id. Check types.
if !types.Identical(tMeth.Type(), uMeth.Type()) {
return false // type mismatch
}
u++
t++
}
return u == ulen
}
func checkEqualButNotIdentical(t *testing.T, x, y types.Type, comment string) {
if !types.Identical(x, y) {
t.Errorf("%s: not equal: %s, %s", comment, x, y)
}
if x == y {
t.Errorf("%s: identical: %v, %v", comment, x, y)
}
}
// At returns the map entry for the given key.
// The result is nil if the entry is not present.
//
func (m *Map) At(key types.Type) interface{} {
if m != nil && m.table != nil {
for _, e := range m.table[m.hasher.Hash(key)] {
if e.key != nil && types.Identical(key, e.key) {
return e.value
}
}
}
return nil
}
// Delete removes the entry with the given key, if any.
// It returns true if the entry was found.
//
func (m *Map) Delete(key types.Type) bool {
if m != nil && m.table != nil {
hash := m.hasher.Hash(key)
bucket := m.table[hash]
for i, e := range bucket {
if e.key != nil && types.Identical(key, e.key) {
// We can't compact the bucket as it
// would disturb iterators.
bucket[i] = entry{}
m.length--
return true
}
}
}
return false
}
// isValuePreserving returns true if a conversion from ut_src to
// ut_dst is value-preserving, i.e. just a change of type.
// Precondition: neither argument is a named type.
//
func isValuePreserving(ut_src, ut_dst types.Type) bool {
// Identical underlying types?
if types.Identical(ut_dst, ut_src) {
return true
}
switch ut_dst.(type) {
case *types.Chan:
// Conversion between channel types?
_, ok := ut_src.(*types.Chan)
return ok
case *types.Pointer:
// Conversion between pointers with identical base types?
_, ok := ut_src.(*types.Pointer)
return ok
}
return false
}
func checkConstValue(t *testing.T, prog *ssa.Program, obj *types.Const) {
c := prog.ConstValue(obj)
// fmt.Printf("ConstValue(%s) = %s\n", obj, c) // debugging
if c == nil {
t.Errorf("ConstValue(%s) == nil", obj)
return
}
if !types.Identical(c.Type(), obj.Type()) {
t.Errorf("ConstValue(%s).Type() == %s", obj, c.Type())
return
}
if obj.Name() != "nil" {
if !exact.Compare(c.Value, token.EQL, obj.Val()) {
t.Errorf("ConstValue(%s).Value (%s) != %s",
obj, c.Value, obj.Val())
return
}
}
}
func checkFuncValue(t *testing.T, prog *ssa.Program, obj *types.Func) {
fn := prog.FuncValue(obj)
// fmt.Printf("FuncValue(%s) = %s\n", obj, fn) // debugging
if fn == nil {
if obj.Name() != "interfaceMethod" {
t.Errorf("FuncValue(%s) == nil", obj)
}
return
}
if fnobj := fn.Object(); fnobj != obj {
t.Errorf("FuncValue(%s).Object() == %s; value was %s",
obj, fnobj, fn.Name())
return
}
if !types.Identical(fn.Type(), obj.Type()) {
t.Errorf("FuncValue(%s).Type() == %s", obj, fn.Type())
return
}
}
// findVisibleErrs returns a mapping from each package-level variable of type "error" to nil.
func findVisibleErrs(prog *ssa.Program, qpos *QueryPos) map[*ssa.Global]ssa.Value {
globals := make(map[*ssa.Global]ssa.Value)
for _, pkg := range prog.AllPackages() {
for _, mem := range pkg.Members {
gbl, ok := mem.(*ssa.Global)
if !ok {
continue
}
gbltype := gbl.Type()
// globals are always pointers
if !types.Identical(deref(gbltype), builtinErrorType) {
continue
}
if !isAccessibleFrom(gbl.Object(), qpos.info.Pkg) {
continue
}
globals[gbl] = nil
}
}
return globals
}
// emitCompare emits to f code compute the boolean result of
// comparison comparison 'x op y'.
//
func emitCompare(f *Function, op token.Token, x, y Value, pos token.Pos) Value {
xt := x.Type().Underlying()
yt := y.Type().Underlying()
// Special case to optimise a tagless SwitchStmt so that
// these are equivalent
// switch { case e: ...}
// switch true { case e: ... }
// if e==true { ... }
// even in the case when e's type is an interface.
// TODO(adonovan): opt: generalise to x==true, false!=y, etc.
if x == vTrue && op == token.EQL {
if yt, ok := yt.(*types.Basic); ok && yt.Info()&types.IsBoolean != 0 {
return y
}
}
if types.Identical(xt, yt) {
// no conversion necessary
} else if _, ok := xt.(*types.Interface); ok {
y = emitConv(f, y, x.Type())
} else if _, ok := yt.(*types.Interface); ok {
x = emitConv(f, x, y.Type())
} else if _, ok := x.(*Const); ok {
x = emitConv(f, x, y.Type())
} else if _, ok := y.(*Const); ok {
y = emitConv(f, y, x.Type())
} else {
// other cases, e.g. channels. No-op.
}
v := &BinOp{
Op: op,
X: x,
Y: y,
}
v.setPos(pos)
v.setType(tBool)
return f.emit(v)
}
func checkVarValue(t *testing.T, prog *ssa.Program, pkg *ssa.Package, ref []ast.Node, obj *types.Var, expKind string, wantAddr bool) {
// The prefix of all assertions messages.
prefix := fmt.Sprintf("VarValue(%s @ L%d)",
obj, prog.Fset.Position(ref[0].Pos()).Line)
v, gotAddr := prog.VarValue(obj, pkg, ref)
// Kind is the concrete type of the ssa Value.
gotKind := "nil"
if v != nil {
gotKind = fmt.Sprintf("%T", v)[len("*ssa."):]
}
// fmt.Printf("%s = %v (kind %q; expect %q) wantAddr=%t gotAddr=%t\n", prefix, v, gotKind, expKind, wantAddr, gotAddr) // debugging
// Check the kinds match.
// "nil" indicates expected failure (e.g. optimized away).
if expKind != gotKind {
t.Errorf("%s concrete type == %s, want %s", prefix, gotKind, expKind)
}
// Check the types match.
// If wantAddr, the expected type is the object's address.
if v != nil {
expType := obj.Type()
if wantAddr {
expType = types.NewPointer(expType)
if !gotAddr {
t.Errorf("%s: got value, want address", prefix)
}
} else if gotAddr {
t.Errorf("%s: got address, want value", prefix)
}
if !types.Identical(v.Type(), expType) {
t.Errorf("%s.Type() == %s, want %s", prefix, v.Type(), expType)
}
}
}
// nil-tolerant variant of types.Identical.
func sameType(x, y types.Type) bool {
if x == nil {
return y == nil
}
return y != nil && types.Identical(x, y)
}
// emitConv emits to f code to convert Value val to exactly type typ,
// and returns the converted value. Implicit conversions are required
// by language assignability rules in assignments, parameter passing,
// etc. Conversions cannot fail dynamically.
//
func emitConv(f *Function, val Value, typ types.Type) Value {
t_src := val.Type()
// Identical types? Conversion is a no-op.
if types.Identical(t_src, typ) {
return val
}
ut_dst := typ.Underlying()
ut_src := t_src.Underlying()
// Just a change of type, but not value or representation?
if isValuePreserving(ut_src, ut_dst) {
c := &ChangeType{X: val}
c.setType(typ)
return f.emit(c)
}
// Conversion to, or construction of a value of, an interface type?
if _, ok := ut_dst.(*types.Interface); ok {
// Assignment from one interface type to another?
if _, ok := ut_src.(*types.Interface); ok {
c := &ChangeInterface{X: val}
c.setType(typ)
return f.emit(c)
}
// Untyped nil constant? Return interface-typed nil constant.
if ut_src == tUntypedNil {
return nilConst(typ)
}
// Convert (non-nil) "untyped" literals to their default type.
if t, ok := ut_src.(*types.Basic); ok && t.Info()&types.IsUntyped != 0 {
val = emitConv(f, val, DefaultType(ut_src))
}
f.Pkg.Prog.needMethodsOf(val.Type())
mi := &MakeInterface{X: val}
mi.setType(typ)
return f.emit(mi)
}
// Conversion of a compile-time constant value?
if c, ok := val.(*Const); ok {
if _, ok := ut_dst.(*types.Basic); ok || c.IsNil() {
// Conversion of a compile-time constant to
// another constant type results in a new
// constant of the destination type and
// (initially) the same abstract value.
// We don't truncate the value yet.
return NewConst(c.Value, typ)
}
// We're converting from constant to non-constant type,
// e.g. string -> []byte/[]rune.
}
// A representation-changing conversion?
// At least one of {ut_src,ut_dst} must be *Basic.
// (The other may be []byte or []rune.)
_, ok1 := ut_src.(*types.Basic)
_, ok2 := ut_dst.(*types.Basic)
if ok1 || ok2 {
c := &Convert{X: val}
c.setType(typ)
return f.emit(c)
}
panic(fmt.Sprintf("in %s: cannot convert %s (%s) to %s", f, val, val.Type(), typ))
}
// Like isTest, but checks the signature too.
func isTestSig(f *Function, prefix string, sig *types.Signature) bool {
return isTest(f.Name(), prefix) && types.Identical(f.Signature, sig)
}
// Ensure that, in debug mode, we can determine the ssa.Value
// corresponding to every ast.Expr.
func TestValueForExpr(t *testing.T) {
conf := loader.Config{ParserMode: parser.ParseComments}
f, err := conf.ParseFile("testdata/valueforexpr.go", nil)
if err != nil {
t.Error(err)
return
}
conf.CreateFromFiles("main", f)
iprog, err := conf.Load()
if err != nil {
t.Error(err)
return
}
mainInfo := iprog.Created[0]
prog := ssa.Create(iprog, 0)
mainPkg := prog.Package(mainInfo.Pkg)
mainPkg.SetDebugMode(true)
mainPkg.Build()
if false {
// debugging
for _, mem := range mainPkg.Members {
if fn, ok := mem.(*ssa.Function); ok {
fn.WriteTo(os.Stderr)
}
}
}
// Find the actual AST node for each canonical position.
parenExprByPos := make(map[token.Pos]*ast.ParenExpr)
ast.Inspect(f, func(n ast.Node) bool {
if n != nil {
if e, ok := n.(*ast.ParenExpr); ok {
parenExprByPos[e.Pos()] = e
}
}
return true
})
// Find all annotations of form /*@kind*/.
for _, c := range f.Comments {
text := strings.TrimSpace(c.Text())
if text == "" || text[0] != '@' {
continue
}
text = text[1:]
pos := c.End() + 1
position := prog.Fset.Position(pos)
var e ast.Expr
if target := parenExprByPos[pos]; target == nil {
t.Errorf("%s: annotation doesn't precede ParenExpr: %q", position, text)
continue
} else {
e = target.X
}
path, _ := astutil.PathEnclosingInterval(f, pos, pos)
if path == nil {
t.Errorf("%s: can't find AST path from root to comment: %s", position, text)
continue
}
fn := ssa.EnclosingFunction(mainPkg, path)
if fn == nil {
t.Errorf("%s: can't find enclosing function", position)
continue
}
v, gotAddr := fn.ValueForExpr(e) // (may be nil)
got := strings.TrimPrefix(fmt.Sprintf("%T", v), "*ssa.")
if want := text; got != want {
t.Errorf("%s: got value %q, want %q", position, got, want)
}
if v != nil {
T := v.Type()
if gotAddr {
T = T.Underlying().(*types.Pointer).Elem() // deref
}
if !types.Identical(T, mainInfo.TypeOf(e)) {
t.Errorf("%s: got type %s, want %s", position, mainInfo.TypeOf(e), T)
}
}
}
}
func (x rtype) eq(_ types.Type, y interface{}) bool {
return types.Identical(x.t, y.(rtype).t)
}
// whicherrs takes an position to an error and tries to find all types, constants
// and global value which a given error can point to and which can be checked from the
// scope where the error lives.
// In short, it returns a list of things that can be checked against in order to handle
// an error properly.
//
// TODO(dmorsing): figure out if fields in errors like *os.PathError.Err
// can be queried recursively somehow.
func whicherrs(o *Oracle, qpos *QueryPos) (queryResult, error) {
path, action := findInterestingNode(qpos.info, qpos.path)
if action != actionExpr {
return nil, fmt.Errorf("whicherrs wants an expression; got %s",
astutil.NodeDescription(qpos.path[0]))
}
var expr ast.Expr
var obj types.Object
switch n := path[0].(type) {
case *ast.ValueSpec:
// ambiguous ValueSpec containing multiple names
return nil, fmt.Errorf("multiple value specification")
case *ast.Ident:
obj = qpos.info.ObjectOf(n)
expr = n
case ast.Expr:
expr = n
default:
return nil, fmt.Errorf("unexpected AST for expr: %T", n)
}
typ := qpos.info.TypeOf(expr)
if !types.Identical(typ, builtinErrorType) {
return nil, fmt.Errorf("selection is not an expression of type 'error'")
}
// Determine the ssa.Value for the expression.
var value ssa.Value
var err error
if obj != nil {
// def/ref of func/var object
value, _, err = ssaValueForIdent(o.prog, qpos.info, obj, path)
} else {
value, _, err = ssaValueForExpr(o.prog, qpos.info, path)
}
if err != nil {
return nil, err // e.g. trivially dead code
}
buildSSA(o)
globals := findVisibleErrs(o.prog, qpos)
constants := findVisibleConsts(o.prog, qpos)
res := &whicherrsResult{
qpos: qpos,
errpos: expr.Pos(),
}
// Find the instruction which initialized the
// global error. If more than one instruction has stored to the global
// remove the global from the set of values that we want to query.
allFuncs := ssautil.AllFunctions(o.prog)
for fn := range allFuncs {
for _, b := range fn.Blocks {
for _, instr := range b.Instrs {
store, ok := instr.(*ssa.Store)
if !ok {
continue
}
gval, ok := store.Addr.(*ssa.Global)
if !ok {
continue
}
gbl, ok := globals[gval]
if !ok {
continue
}
// we already found a store to this global
// The normal error define is just one store in the init
// so we just remove this global from the set we want to query
if gbl != nil {
delete(globals, gval)
}
globals[gval] = store.Val
}
}
}
o.ptaConfig.AddQuery(value)
for _, v := range globals {
o.ptaConfig.AddQuery(v)
}
ptares := ptrAnalysis(o)
valueptr := ptares.Queries[value]
for g, v := range globals {
ptr, ok := ptares.Queries[v]
if !ok {
continue
}
if !ptr.MayAlias(valueptr) {
continue
}
res.globals = append(res.globals, g)
}
pts := valueptr.PointsTo()
dedup := make(map[*ssa.NamedConst]bool)
for _, label := range pts.Labels() {
// These values are either MakeInterfaces or reflect
// generated interfaces. For the purposes of this
// analysis, we don't care about reflect generated ones
makeiface, ok := label.Value().(*ssa.MakeInterface)
if !ok {
continue
}
constval, ok := makeiface.X.(*ssa.Const)
if !ok {
continue
}
c := constants[*constval]
if c != nil && !dedup[c] {
dedup[c] = true
res.consts = append(res.consts, c)
}
}
concs := pts.DynamicTypes()
concs.Iterate(func(conc types.Type, _ interface{}) {
// go/types is a bit annoying here.
// We want to find all the types that we can
// typeswitch or assert to. This means finding out
// if the type pointed to can be seen by us.
//
// For the purposes of this analysis, the type is always
// either a Named type or a pointer to one.
// There are cases where error can be implemented
// by unnamed types, but in that case, we can't assert to
// it, so we don't care about it for this analysis.
var name *types.TypeName
switch t := conc.(type) {
case *types.Pointer:
named, ok := t.Elem().(*types.Named)
if !ok {
return
}
name = named.Obj()
case *types.Named:
name = t.Obj()
default:
return
}
if !isAccessibleFrom(name, qpos.info.Pkg) {
return
}
res.types = append(res.types, &errorType{conc, name})
})
sort.Sort(membersByPosAndString(res.globals))
sort.Sort(membersByPosAndString(res.consts))
sort.Sort(sorterrorType(res.types))
return res, nil
}
// Implements displays the "implements" relation as it pertains to the
// selected type. If the selection is a method, 'implements' displays
// the corresponding methods of the types that would have been reported
// by an implements query on the receiver type.
//
func implements(o *Oracle, qpos *QueryPos) (queryResult, error) {
// Find the selected type.
path, action := findInterestingNode(qpos.info, qpos.path)
var method *types.Func
var T types.Type // selected type (receiver if method != nil)
switch action {
case actionExpr:
// method?
if id, ok := path[0].(*ast.Ident); ok {
if obj, ok := qpos.info.ObjectOf(id).(*types.Func); ok {
recv := obj.Type().(*types.Signature).Recv()
if recv == nil {
return nil, fmt.Errorf("this function is not a method")
}
method = obj
T = recv.Type()
}
}
case actionType:
T = qpos.info.TypeOf(path[0].(ast.Expr))
}
if T == nil {
return nil, fmt.Errorf("no type or method here")
}
// Find all named types, even local types (which can have
// methods via promotion) and the built-in "error".
//
// TODO(adonovan): include all packages in PTA scope too?
// i.e. don't reduceScope?
//
var allNamed []types.Type
for _, info := range o.typeInfo {
for _, obj := range info.Defs {
if obj, ok := obj.(*types.TypeName); ok {
allNamed = append(allNamed, obj.Type())
}
}
}
allNamed = append(allNamed, types.Universe.Lookup("error").Type())
var msets types.MethodSetCache
// Test each named type.
var to, from, fromPtr []types.Type
for _, U := range allNamed {
if isInterface(T) {
if msets.MethodSet(T).Len() == 0 {
continue // empty interface
}
if isInterface(U) {
if msets.MethodSet(U).Len() == 0 {
continue // empty interface
}
// T interface, U interface
if !types.Identical(T, U) {
if types.AssignableTo(U, T) {
to = append(to, U)
}
if types.AssignableTo(T, U) {
from = append(from, U)
}
}
} else {
// T interface, U concrete
if types.AssignableTo(U, T) {
to = append(to, U)
} else if pU := types.NewPointer(U); types.AssignableTo(pU, T) {
to = append(to, pU)
}
}
} else if isInterface(U) {
if msets.MethodSet(U).Len() == 0 {
continue // empty interface
}
// T concrete, U interface
if types.AssignableTo(T, U) {
from = append(from, U)
} else if pT := types.NewPointer(T); types.AssignableTo(pT, U) {
fromPtr = append(fromPtr, U)
}
}
}
var pos interface{} = qpos
if nt, ok := deref(T).(*types.Named); ok {
pos = nt.Obj()
}
// Sort types (arbitrarily) to ensure test determinism.
sort.Sort(typesByString(to))
sort.Sort(typesByString(from))
sort.Sort(typesByString(fromPtr))
var toMethod, fromMethod, fromPtrMethod []*types.Selection // contain nils
if method != nil {
for _, t := range to {
toMethod = append(toMethod,
types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
}
for _, t := range from {
fromMethod = append(fromMethod,
types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
}
for _, t := range fromPtr {
fromPtrMethod = append(fromPtrMethod,
types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
}
}
return &implementsResult{qpos, T, pos, to, from, fromPtr, method, toMethod, fromMethod, fromPtrMethod}, nil
}
// peers enumerates, for a given channel send (or receive) operation,
// the set of possible receives (or sends) that correspond to it.
//
// TODO(adonovan): support reflect.{Select,Recv,Send,Close}.
// TODO(adonovan): permit the user to query based on a MakeChan (not send/recv),
// or the implicit receive in "for v := range ch".
func peers(o *Oracle, qpos *QueryPos) (queryResult, error) {
opPos := findOp(qpos)
if opPos == token.NoPos {
return nil, fmt.Errorf("there is no channel operation here")
}
buildSSA(o)
var queryOp chanOp // the originating send or receive operation
var ops []chanOp // all sends/receives of opposite direction
// Look at all channel operations in the whole ssa.Program.
// Build a list of those of same type as the query.
allFuncs := ssautil.AllFunctions(o.prog)
for fn := range allFuncs {
for _, b := range fn.Blocks {
for _, instr := range b.Instrs {
for _, op := range chanOps(instr) {
ops = append(ops, op)
if op.pos == opPos {
queryOp = op // we found the query op
}
}
}
}
}
if queryOp.ch == nil {
return nil, fmt.Errorf("ssa.Instruction for send/receive not found")
}
// Discard operations of wrong channel element type.
// Build set of channel ssa.Values as query to pointer analysis.
// We compare channels by element types, not channel types, to
// ignore both directionality and type names.
queryType := queryOp.ch.Type()
queryElemType := queryType.Underlying().(*types.Chan).Elem()
o.ptaConfig.AddQuery(queryOp.ch)
i := 0
for _, op := range ops {
if types.Identical(op.ch.Type().Underlying().(*types.Chan).Elem(), queryElemType) {
o.ptaConfig.AddQuery(op.ch)
ops[i] = op
i++
}
}
ops = ops[:i]
// Run the pointer analysis.
ptares := ptrAnalysis(o)
// Find the points-to set.
queryChanPtr := ptares.Queries[queryOp.ch]
// Ascertain which make(chan) labels the query's channel can alias.
var makes []token.Pos
for _, label := range queryChanPtr.PointsTo().Labels() {
makes = append(makes, label.Pos())
}
sort.Sort(byPos(makes))
// Ascertain which channel operations can alias the same make(chan) labels.
var sends, receives, closes []token.Pos
for _, op := range ops {
if ptr, ok := ptares.Queries[op.ch]; ok && ptr.MayAlias(queryChanPtr) {
switch op.dir {
case types.SendOnly:
sends = append(sends, op.pos)
case types.RecvOnly:
receives = append(receives, op.pos)
case types.SendRecv:
closes = append(closes, op.pos)
}
}
}
sort.Sort(byPos(sends))
sort.Sort(byPos(receives))
sort.Sort(byPos(closes))
return &peersResult{
queryPos: opPos,
queryType: queryType,
makes: makes,
sends: sends,
receives: receives,
closes: closes,
}, nil
}