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go/types: remove the concept of finals

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Checker.finals and the corresponding atEnd were added in CL 191418 as a
mechanism to postpone interface type comparison until after all
interfaces were complete. In the intervening CL 195837 we've adopted a
convention of ensuring that interfaces are complete before comparing
them. Since then we've also added the additional case of expansion for
lazily resolving syntax.

Checker.later defers resolution of types until points in the checking
pass where all reachable types can be fully type checked, so the concept
of finals should no longer be necessary.

Change-Id: I58818c1a6b605dccc9b0ecb3a1f6859c138175d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/299590
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This commit is contained in:
Rob Findley 2021-03-08 23:38:42 -05:00 committed by Robert Findley
parent 62cad233a6
commit b3a5640397
2 changed files with 6 additions and 27 deletions
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21
src/go/types/check.go
View File

@ -104,7 +104,6 @@ type Checker struct {
methods map[*TypeName][]*Func // maps package scope type names to associated non-blank (non-interface) methods
untyped map[ast.Expr]exprInfo // map of expressions without final type
delayed []func() // stack of delayed action segments; segments are processed in FIFO order
finals []func() // list of final actions; processed at the end of type-checking the current set of files
objPath []Object // path of object dependencies during type inference (for cycle reporting)
// context within which the current object is type-checked
@ -144,14 +143,6 @@ func (check *Checker) later(f func()) {
check.delayed = append(check.delayed, f)
}
// atEnd adds f to the list of actions processed at the end
// of type-checking, before initialization order computation.
// Actions added by atEnd are processed after any actions
// added by later.
func (check *Checker) atEnd(f func()) {
check.finals = append(check.finals, f)
}
// push pushes obj onto the object path and returns its index in the path.
func (check *Checker) push(obj Object) int {
check.objPath = append(check.objPath, obj)
@ -212,7 +203,6 @@ func (check *Checker) initFiles(files []*ast.File) {
check.methods = nil
check.untyped = nil
check.delayed = nil
check.finals = nil
// determine package name and collect valid files
pkg := check.pkg
@ -269,7 +259,6 @@ func (check *Checker) checkFiles(files []*ast.File) (err error) {
check.packageObjects()
check.processDelayed(0) // incl. all functions
check.processFinals()
check.initOrder()
@ -308,16 +297,6 @@ func (check *Checker) processDelayed(top int) {
check.delayed = check.delayed[:top]
}
func (check *Checker) processFinals() {
n := len(check.finals)
for _, f := range check.finals {
f() // must not append to check.finals
}
if len(check.finals) != n {
panic("internal error: final action list grew")
}
}
func (check *Checker) recordUntyped() {
if !debug && check.Types == nil {
return // nothing to do

12
src/go/types/typexpr.go
View File

@ -140,7 +140,7 @@ func (check *Checker) ordinaryType(pos positioner, typ Type) {
// while we are in the middle of type-checking parameter declarations that
// might belong to interface methods. Delay this check to the end of
// type-checking.
check.atEnd(func() {
check.later(func() {
if t := asInterface(typ); t != nil {
check.completeInterface(pos.Pos(), t) // TODO(gri) is this the correct position?
if t.allTypes != nil {
@ -531,7 +531,7 @@ func (check *Checker) typInternal(e0 ast.Expr, def *Named) (T Type) {
//
// Delay this check because it requires fully setup types;
// it is safe to continue in any case (was issue 6667).
check.atEnd(func() {
check.later(func() {
if !Comparable(typ.key) {
var why string
if asTypeParam(typ.key) != nil {
@ -635,7 +635,7 @@ func (check *Checker) instantiatedType(x ast.Expr, targs []ast.Expr, def *Named)
// make sure we check instantiation works at least once
// and that the resulting type is valid
check.atEnd(func() {
check.later(func() {
t := typ.expand()
check.validType(t, nil)
})
@ -905,7 +905,7 @@ func (check *Checker) completeInterface(pos token.Pos, ityp *Interface) {
// If we're pre-go1.14 (overlapping embeddings are not permitted), report that
// error here as well (even though we could do it eagerly) because it's the same
// error message.
check.atEnd(func() {
check.later(func() {
if !check.allowVersion(m.pkg, 1, 14) || !check.identical(m.typ, other.Type()) {
check.errorf(atPos(pos), _DuplicateDecl, "duplicate method %s", m.name)
check.errorf(atPos(mpos[other.(*Func)]), _DuplicateDecl, "\tother declaration of %s", m.name) // secondary error, \t indented
@ -1119,7 +1119,7 @@ func (check *Checker) structType(styp *Struct, e *ast.StructType) {
embeddedTyp := typ
embeddedPos := f.Type
check.atEnd(func() {
check.later(func() {
t, isPtr := deref(embeddedTyp)
switch t := optype(t).(type) {
case *Basic:
@ -1177,7 +1177,7 @@ func (check *Checker) collectTypeConstraints(pos token.Pos, types []ast.Expr) []
// interfaces, which may not be complete yet. It's ok to do this check at the
// end because it's not a requirement for correctness of the code.
// Note: This is a quadratic algorithm, but type lists tend to be short.
check.atEnd(func() {
check.later(func() {
for i, t := range list {
if t := asInterface(t); t != nil {
check.completeInterface(types[i].Pos(), t)