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cmd/compile/internal/types2: rename Checker.cycle to Checker.validCycle

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Also, invert the boolean result. This matches Checker.validType;
it's also easier to understand. Preparation for the next CL which
detects cycles through type parameter lists.

Change-Id: I00a75d2359ca20827c9bf406945508716c826fc4
Reviewed-on: https://go-review.googlesource.com/c/go/+/362336
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer 2021-11-08 20:17:22 -08:00
parent ec86bb52ba
commit 318c024b49
1 changed files with 11 additions and 12 deletions
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23
src/cmd/compile/internal/types2/decl.go
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@ -124,7 +124,7 @@ func (check *Checker) objDecl(obj Object, def *Named) {
fallthrough
case grey:
// We have a cycle.
// We have a (possibly invalid) cycle.
// In the existing code, this is marked by a non-nil type
// for the object except for constants and variables whose
// type may be non-nil (known), or nil if it depends on the
@ -136,17 +136,17 @@ func (check *Checker) objDecl(obj Object, def *Named) {
// order code.
switch obj := obj.(type) {
case *Const:
if check.cycle(obj) || obj.typ == nil {
if !check.validCycle(obj) || obj.typ == nil {
obj.typ = Typ[Invalid]
}
case *Var:
if check.cycle(obj) || obj.typ == nil {
if !check.validCycle(obj) || obj.typ == nil {
obj.typ = Typ[Invalid]
}
case *TypeName:
if check.cycle(obj) {
if !check.validCycle(obj) {
// break cycle
// (without this, calling underlying()
// below may lead to an endless loop
@ -156,7 +156,7 @@ func (check *Checker) objDecl(obj Object, def *Named) {
}
case *Func:
if check.cycle(obj) {
if !check.validCycle(obj) {
// Don't set obj.typ to Typ[Invalid] here
// because plenty of code type-asserts that
// functions have a *Signature type. Grey
@ -210,9 +210,9 @@ func (check *Checker) objDecl(obj Object, def *Named) {
}
}
// cycle checks if the cycle starting with obj is valid and
// validCycle reports whether the cycle starting with obj is valid and
// reports an error if it is not.
func (check *Checker) cycle(obj Object) (isCycle bool) {
func (check *Checker) validCycle(obj Object) (valid bool) {
// The object map contains the package scope objects and the non-interface methods.
if debug {
info := check.objMap[obj]
@ -264,7 +264,7 @@ func (check *Checker) cycle(obj Object) (isCycle bool) {
check.trace(obj.Pos(), "## cycle detected: objPath = %s->%s (len = %d)", pathString(cycle), obj.Name(), len(cycle))
check.trace(obj.Pos(), "## cycle contains: %d values, %d type definitions", nval, ndef)
defer func() {
if isCycle {
if !valid {
check.trace(obj.Pos(), "=> error: cycle is invalid")
}
}()
@ -274,19 +274,18 @@ func (check *Checker) cycle(obj Object) (isCycle bool) {
// ignore them here because they are reported via the initialization
// cycle check.
if nval == len(cycle) {
return false
return true
}
// A cycle involving only types (and possibly functions) must have at least
// one type definition to be permitted: If there is no type definition, we
// have a sequence of alias type names which will expand ad infinitum.
if nval == 0 && ndef > 0 {
return false // cycle is permitted
return true
}
check.cycleError(cycle)
return true
return false
}
type typeInfo uint