Nested accessors and methods

[jackbsteinberg]

Currently when the rewriter encounters nested accessors and methods it will only convert the outermost to its original:

const pathLength = url.pathname.length;
const expressionName = node.getExpression().getSymbol().getName();

---- REWRITTEN ----

const pathLength = Reflect_apply(String_length_get, url.pathName);
const expressionName = Reflect_apply(Symbol_getName, node.getExpression().getSymbol(), []);

This is possibly because parents of observed nodes are being rewritten, which prevents the algorithm from continuing to inspect and properly rewrite all the children.

[domenic]

Solutions discussed:

• First, refactor all codemods so that you never replace the parent node. This might magically solve the problem, depending on the implementation details of ts-morph's forEachDescendant().

• If that does not solve the problem, then implement our own depth-first postorder traversal to replace forEachDescendant(). This depends on the previous step; a depth-first postorder traversal will fail badly if we're replacing the parents of nodes that are in the process of being traversed.

[domenic]

This may be more complicated than just applying the transforms recursively, because the first transform could cause a loss of type information. See #35 (comment) for a similar issue and a proposed solution.

[fergald]

Reopening based on #69 (comment)