go/types: rename Checker.cycle to Checker.validCycle

This is a clean port of CL 362336 to go/types.

Change-Id: Iafeae7024fbb2872b07748affcea9676324ea59e
Reviewed-on: https://go-review.googlesource.com/c/go/+/362755
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>

diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index 8d255dcf3d12bfc78e6b136a9c608a837b1032af..eccdec9a039170d8a960433ea1928bca1b8cbd15 100644 (file)
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -123,7 +123,7 @@ 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
@@ -135,17 +135,17 @@ 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
@@ -155,7 +155,7 @@ 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
@@ -209,9 +209,9 @@ func (check *Checker) objDecl(obj Object, def *Named) {
        }
 }
 
-// cycle checks if the cycle starting with obj is valid and
+// validCycle checks if 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]
@@ -263,7 +263,7 @@ 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")
                        }
                }()
@@ -273,19 +273,18 @@ 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