• 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

typeTestTest1=ReadonlyArray<string>&Readonly<{foo:string;}>;typeTestTest2=Readonly<ReadonlyArray<string>>&Readonly<{foo:string;}>;

isTypeReadonly(checker,type,{})

Expected Result

isTypeReadonly should returntrue

Actual Result

isTypeReadonly returnsfalse

Additional Info

The error seems to be that TypeScript treatsReadonly<ReadonlyArray<string>> the same asReadonlyArray<string> and thus the methods are still mutable. We need a special case to handle intersections with readonly arrays.

Versions