• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I haveread the FAQ and my problem is not listed.

Repro

{"rules": {"@typescript-eslint/no-non-null-asserted-optional-chain":"error"  }}

letfoo1:{bar:{baz:string}}|undefined;console.log(foo1?.bar!.baz);

Expected Result

ESLint reports error.

Actual Result

Infinite Loop.

Additional Info

I am using ESLint programmatically:

import{CLIEngine,Linter}from'eslint';constcli=newCLIEngine({});cli.executeOnFiles('/path/to/the/file.ts');

But the script never ended. However this problem was not present in VSCode ESLint Plugin. I have no idea about what's happening. I am not sure the above code can reproduce the problem (because it is extracted from a large codebase).

I used the debugger to pause when infinite loop occurred. It ended up here:

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/src/rules/no-non-null-asserted-optional-chain.ts#L116

There is an obvious logical error: thebreak only breaks theswitch statement, meanwhilecurrent.optional is truthy, meaningcurrent is truthy. TheoreticallyTHE LOOP WILL NEVER STOP WHEN A OPTIONAL CHAIN IS FOUND.

while(current){switch(current.type){caseAST_NODE_TYPES.MemberExpression:if(current.optional){// found an optional chain! stop traversingbreak;}current=current.object;continue;caseAST_NODE_TYPES.CallExpression:if(current.optional){// found an optional chain! stop traversingbreak;}current=current.callee;continue;default:// something that's not a ChainElement, which means this is not an optional chain we want to checkreturn;}}

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