Regression: RangeError: Maximum call stack size exceeded in type instantiation with recursive types and intersections

🔎 Search Terms

Maximum call stack size exceeded

instantiateTypeWithAlias

Infinite recursion crash

Regression 5.9

🕗 Version & Regression Information

5.7.3: Works (Emits TS2589)

5.8.3: Works (Emits TS2589)

5.9.3: Crashes

Nightly: Crashes

⏯ Playground Link

https://www.typescriptlang.org/zh/play/?target=7&ts=6.0.0-dev.20260108#code/PTAECUFMAcCcHtQDMEFtQGIDMBGAHAExYCwAUJAB7TywAuotAntJKAAqwyQB2AJgDwBRADaoANKAAqoSrR68AzqACu3ANbd4Ad24BtALoA+UAF4yUmRTl8lqjdu6gA-OYAUrgIawA5gC5QIuKgAHShnAq0-pIAlKbGAG7wAJa8sbLySu6hwV7eCv5J3EiQsFIEsSYJyanOZaD+5tyQ8SX1jc0lANxklNR0DMysghQeAMa0w7SwY7T8khIAqsYmoK7S6TagC7XbG4oWThb+TS2lxx2wsQBkoBGwhd7dpEwsoADC8Nzxc4umUsugcwAb1AAAZ-LpJPpOqAcP4OFw+D93p9vsMZpNpuN+AsJJJDATOgBfXS7KwZA5g+qw6FAA

💻 Code

// Repro from #31823
export type Prepend<Elm, T extends unknown[]> =
 T extends unknown ?
 ((arg: Elm, ...rest: T) => void) extends ((...args: infer T2) => void) ? T2 : 
 never :
 never;
//export type ExactExtract<T, U> = (T extends U ? U extends T ? T : never : never) & boolean;
export type ExactExtract<T, U> = (T extends U ? U extends T ? T : never : never) & string;
type Conv<T, U = T> = 
 { 0: [T]; 1: Prepend<T, Conv<ExactExtract<U, T>>>;}[U extends T ? 0 : 1];

🙁 Actual behavior

 .\ts-versions\nightly\node_modules\.bin\tsc.cmd  C:\Users\aw\Desktop\itr-new\result0\mutated\infiniteConstraints_mutated_iter9.ts
D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:123181
      throw e;
      ^

RangeError: Maximum call stack size exceeded
    at instantiateType (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63527:27)                                                                                                 
    at instantiateList (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63154:24)                                                                                                 
    at instantiateTypes (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63168:12)                                                                                                
    at instantiateTypeWorker (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63592:24)                                                                                           
    at instantiateTypeWithAlias (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63560:20)                                                                                        
    at instantiateType (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63528:29)                                                                                                 
    at getMappedType (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63208:67)                                                                                                   
    at D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63513:66
    at map (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:196:19)                                                                                                               
    at getConditionalTypeInstantiation (D:\do\typeFuzz\ts-versions\nightly\node_modules\typescript\lib\_tsc.js:63513:29)                                                                                 

Node.js v22.19.0

If I change the intersection type in ExactExtract from & string to & boolean, the compiler's behavior changes from a crash to a hang.

🙂 Expected behavior

The compiler should not crash.

Additional information about the issue

No response