treeshaker should keep [Symbol.iterator]-members because there are implict...

treeshaker should keep [Symbol.iterator]-members because there are implict references from for-of loops

build/lib/treeshaking.js

@@ -422,6 +422,7 @@ function markNodes(languageService, options) {
                                 || ts.isConstructSignatureDeclaration(member)
                                 || ts.isIndexSignatureDeclaration(member)
                                 || ts.isCallSignatureDeclaration(member)
+                                || memberName === '[Symbol.iterator]'
                                 || memberName === 'toJSON'
                                 || memberName === 'toString'
                                 || memberName === 'dispose' // TODO: keeping all `dispose` methods

build/lib/treeshaking.ts

@@ -540,6 +540,7 @@ function markNodes(languageService: ts.LanguageService, options: ITreeShakingOpt
 								|| ts.isConstructSignatureDeclaration(member)
 								|| ts.isIndexSignatureDeclaration(member)
 								|| ts.isCallSignatureDeclaration(member)
+								|| memberName === '[Symbol.iterator]'
 								|| memberName === 'toJSON'
 								|| memberName === 'toString'
 								|| memberName === 'dispose'// TODO: keeping all `dispose` methods