terraform: don't crash if validating orphan

terraform/context.go

@@ -1053,14 +1053,16 @@ func (c *walkContext) validateWalkFn() depgraph.WalkFunc {
 
 			// If the resouce name doesn't match the name regular
 			// expression, show a warning.
-			if !config.NameRegexp.Match([]byte(rn.Config.Name)) {
-				l.Lock()
-				meta.Warns = append(meta.Warns, fmt.Sprintf(
-					"%s: module name can only contain letters, numbers, "+
-						"dashes, and underscores.\n"+
-						"This will be an error in Terraform 0.4",
-					rn.Resource.Id))
-				l.Unlock()
+			if rn.Config != nil {
+				if !config.NameRegexp.Match([]byte(rn.Config.Name)) {
+					l.Lock()
+					meta.Warns = append(meta.Warns, fmt.Sprintf(
+						"%s: module name can only contain letters, numbers, "+
+							"dashes, and underscores.\n"+
+							"This will be an error in Terraform 0.4",
+						rn.Resource.Id))
+					l.Unlock()
+				}
 			}
 
 			log.Printf("[INFO] Validating resource: %s", rn.Resource.Id)