Go: Don't extract objects for type aliases

Author: mbg

go/extractor/extractor.go

@@ -522,14 +522,14 @@ func extractObjectTypes(tw *trap.Writer) {
 // For more information on objects, see:
 // https://github.com/golang/example/blob/master/gotypes/README.md#objects
 func extractObjectType(tw *trap.Writer, obj types.Object, lbl trap.Label) {
-	if tp := obj.Type(); tp != nil {
+	if tp := obj.Type(); tp != nil && !isAlias(tp) {
 		extractType(tw, tp)
 	}
 }
 
 // emitObjectType emits the type information for a given object
 func emitObjectType(tw *trap.Writer, obj types.Object, lbl trap.Label) {
-	if tp := obj.Type(); tp != nil {
+	if tp := obj.Type(); tp != nil && !isAlias(tp) {
 		dbscheme.ObjectTypesTable.Emit(tw, lbl, extractType(tw, tp))
 	}
 }
@@ -1516,7 +1516,7 @@ func isAlias(tp types.Type) bool {
 // If the given type is a type alias, this function resolves it to its underlying type.
 func resolveTypeAlias(tp types.Type) types.Type {
 	if isAlias(tp) {
-		return tp.Underlying()
+		return types.Unalias(tp) // tp.Underlying()
 	}
 	return tp
 }