Plumb through set rather than converting to slice

pkg/composableschemadsl/compiler/translator.go

@@ -23,7 +23,7 @@ type translationContext struct {
 	mapper           input.PositionMapper
 	schemaString     string
 	skipValidate     bool
-	existingNames    []string
+	existingNames    *mapz.Set[string]
 	sourceFolder     string
 }
 
@@ -51,7 +51,9 @@ func translate(tctx translationContext, root *dslNode) (*CompiledSchema, error)
 	var objectDefinitions []*core.NamespaceDefinition
 	var caveatDefinitions []*core.CaveatDefinition
 
-	names := mapz.NewSet(tctx.existingNames...)
+	// Copy the name set so that we're not mutating the parent's context
+	// as we do our walk
+	names := tctx.existingNames.Copy()
 
 	for _, topLevelNode := range root.GetChildren() {
 		switch topLevelNode.GetType() {