Calling binaryen.getExpressionInfo(exprRef) with an unreachable function body throws

[fallow64]

Calling binaryen.getExpressionInfo(exprRef) with the reference of the body where it's only instruction is unreachable causes the following JS error:

TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at A.getExpressionInfo (file:///Users/austin/dev/fallow64-binaryen-js-issue-example/node_modules/binaryen/index.js:8:4495)
    at main (/Users/austin/dev/fallow64-binaryen-js-issue-example/src/main.ts:28:38)
    at /Users/austin/dev/fallow64-binaryen-js-issue-example/src/main.ts:34:1
    at async Function.import (/Users/austin/dev/fallow64-binaryen-js-issue-example/node_modules/jiti/dist/jiti.cjs:1:202945)
    at async file:///Users/austin/dev/fallow64-binaryen-js-issue-example/node_modules/jiti/lib/jiti-cli.mjs:31:1

I'm unfamiliar with the codebase so I'm not too sure if it's the expression information resolving that's causing the issue, the function parser, or something else. Seems to be a regression due to 1.124.0. Changing the dependency in package.json of the example to ^123.0.0 resolves the issue.

Example repo: https://github.com/fallow64/fallow64-binaryen-js-issue-example

Tested platforms: MacOS, Windows

Thanks :)

[CountBleck]

This should be reported to [Binaryen. This repo only contains the automated builds and ships the npm package with some TS declarations; the JS bindings themselves are over on the Binaryen repo.

This regression looks like it comes from WebAssembly/binaryen#7525...looks like the new logic doesn't handle unreachable instructions, and it probably doesn't handle a standalone nop instruction either, since neither have "expression wrappers" created by makeExpressionWrapper, and those are necessary for the new logic to work.

As a sidenote (not really relevant to fixing the issue), the reason why adding a nop before the unreachable works in your simple.wat example (I'm guessing; I didn't try it out myself) is because the function body gets represented as a block instruction.

[fallow64]

Ah great thanks!