“Lexical environment is not suspended” when visitEachChile

[cqzooge]

🔎 Search Terms

Lexical environment is not suspended

🕗 Version & Regression Information

• This is a crash (assert error) 4.9.5 I try to use the master bransh, and have the same problem

⏯ Playground Link

No response

💻 Code

function f(): {get a(): void} | void {}

🙁 Actual behavior

function f(): {get a(): void} | void {}

this code won't report error in playground, but if we parse this code and use visitEachChild to visit each node with transform context we will have crash like

Error: Debug Failure. False expression: Lexical environment is suspended.

the test code:

const ts = require("typescript")

function test2() {
    const sourceCode = "function f(): {get a(): void} | void {}";
    const result = ts.transpileModule(sourceCode, {
        transformers: {before: [createVisiter] }
    })
    console.log(result.outputText);
}

function createVisiter(context) {
    return (node) => visit(node);
    function visit(node) {
        return ts.visitEachChild(node, visit, context);
    }
}

test2()

🙂 Expected behavior

don't have assert error when we visitEachChild

Additional information about the issue

seems the reason is that we set lexicalEnvironmentSuspended as true after visit ParameterList, and before visit FunctionBody. But if we have something between ParameterList and FunctionBody and need check lexicalEnvironmentSuspended, we will have assert error. like get/set accessor

so if we add a objectliteral type with get/set accessor as the return type of a function or method or get/set accessor, we will have crash when we use visitEachChild to visit the nodes

Is it a bug? or I use something wrong?

[rbuckton]

This certainly looks like a bug, we try to push a new lexical environment for the get/set while processing them as declarations in a type when we shouldn't.

[cqzooge]

thanks，when will this problem fixed？

by the way, what does lexicalEnvironmentSuspended used for?

[fatcerberus]

wait, why are we visiting Chile again

[RyanCavanaugh]

'cuz I'm a forEach chile ya hear, lord knows I'm a forEach chile

https://youtu.be/rb53-sDII0o