you cannot refer to destroy nodes

Outputs and locals cannot refer to destroy nodes. Since those nodes
types do not have different ordering for create and destroy operations,
connecting them directly to destroy nodes can cause cycles.

terraform/node_local.go

@@ -55,7 +55,7 @@ func (n *nodeExpandLocal) ReferenceableAddrs() []addrs.Referenceable {
 // GraphNodeReferencer
 func (n *nodeExpandLocal) References() []*addrs.Reference {
 	refs, _ := lang.ReferencesInExpr(n.Config.Expr)
-	return appendResourceDestroyReferences(refs)
+	return refs
 }
 
 func (n *nodeExpandLocal) DynamicExpand(ctx EvalContext) (*Graph, error) {
@@ -117,7 +117,7 @@ func (n *NodeLocal) ReferenceableAddrs() []addrs.Referenceable {
 // GraphNodeReferencer
 func (n *NodeLocal) References() []*addrs.Reference {
 	refs, _ := lang.ReferencesInExpr(n.Config.Expr)
-	return appendResourceDestroyReferences(refs)
+	return refs
 }
 
 // GraphNodeEvalable

terraform/node_module_expand.go

@@ -68,7 +68,7 @@ func (n *nodeExpandModule) References() []*addrs.Reference {
 		forEachRefs, _ := lang.ReferencesInExpr(n.ModuleCall.ForEach)
 		refs = append(refs, forEachRefs...)
 	}
-	return appendResourceDestroyReferences(refs)
+	return refs
 }
 
 func (n *nodeExpandModule) DependsOn() []*addrs.Reference {

terraform/node_output.go

@@ -96,7 +96,7 @@ func (n *nodeExpandOutput) ReferenceOutside() (selfPath, referencePath addrs.Mod
 
 // GraphNodeReferencer
 func (n *nodeExpandOutput) References() []*addrs.Reference {
-	return appendResourceDestroyReferences(referencesForOutput(n.Config))
+	return referencesForOutput(n.Config)
 }
 
 // NodeApplyableOutput represents an output that is "applyable":
@@ -190,7 +190,7 @@ func referencesForOutput(c *configs.Output) []*addrs.Reference {
 
 // GraphNodeReferencer
 func (n *NodeApplyableOutput) References() []*addrs.Reference {
-	return appendResourceDestroyReferences(referencesForOutput(n.Config))
+	return referencesForOutput(n.Config)
 }
 
 // GraphNodeEvalable

terraform/transform_reference.go

@@ -501,31 +501,6 @@ func ReferencesFromConfig(body hcl.Body, schema *configschema.Block) []*addrs.Re
 	return refs
 }
 
-// appendResourceDestroyReferences identifies resource and resource instance
-// references in the given slice and appends to it the "destroy-phase"
-// equivalents of those references, returning the result.
-//
-// This can be used in the References implementation for a node which must also
-// depend on the destruction of anything it references.
-func appendResourceDestroyReferences(refs []*addrs.Reference) []*addrs.Reference {
-	given := refs
-	for _, ref := range given {
-		switch tr := ref.Subject.(type) {
-		case addrs.Resource:
-			newRef := *ref // shallow copy
-			newRef.Subject = tr.Phase(addrs.ResourceInstancePhaseDestroy)
-			refs = append(refs, &newRef)
-		case addrs.ResourceInstance:
-			newRef := *ref // shallow copy
-			newRef.Subject = tr.Phase(addrs.ResourceInstancePhaseDestroy)
-			refs = append(refs, &newRef)
-		}
-		// FIXME: Using this method in module expansion references,
-		// May want to refactor this method beyond resources
-	}
-	return refs
-}
-
 func modulePrefixStr(p addrs.ModuleInstance) string {
 	return p.String()
 }