Remove unused combination evidence and helpers

internal/engine/inheritance.go

@@ -129,15 +129,11 @@ func projectInheritancePolicyTemplates(templates []collectionPolicyScope, prefix
 	return projected
 }
 
-// A replacement retains the displaced source/derivation record while the
-// effective origin belongs to the child. Value trees are borrowed immutable
-// inputs or detached templates and are budgeted with retained history later.
+// A replacement retains the before and after values for history accounting.
+// The trees are borrowed immutable inputs or detached templates.
 type inheritanceReplacement struct {
-	path      Path
-	before    *document.Node
-	after     *document.Node
-	previous  []displacedDefinition
-	effective Origin
+	before *document.Node
+	after  *document.Node
 }
 
 // A link represents one shared relationship edge. Each contributor retains
@@ -173,11 +169,6 @@ func inheritanceDirective(node *document.Node) (document.Entry, bool) {
 	return document.Entry{}, false
 }
 
-func inheritanceDirectiveLocation(node *document.Node) Location {
-	entry, _ := inheritanceDirective(node)
-	return publicLocation(entry.Value.Location)
-}
-
 func withoutInheritanceDirective(node *document.Node) *document.Node {
 	payload := *node
 	payload.Mapping = make([]document.Entry, 0, len(node.Mapping))