[NewErrors] 4.6.0-dev.20211107 vs 4.4.4

[typescript-bot]

The following errors were reported by 4.6.0-dev.20211107, but not by 4.4.4

react-hook-form/react-hook-form

2 of 3 projects failed to build with the old tsc

tsconfig.json

• error TS2322: Type 'UseFormReturn<FormFieldsBig, object>' is not assignable to type 'Omit<UseFormReturn<FormFieldsSmall, object>, "watch">'.
  • src/tests/type.test.tsx#L44
• error TS2322: Type 'UseFormRegister<FieldValues>' is not assignable to type 'UseFormRegister<FormValues>'.
  • src/tests/useForm/register.test.tsx#L756
• error TS2345: Argument of type 'UnpackNestedValue<PathValue<TFieldValues, TFieldName>>' is not assignable to parameter of type 'UnpackNestedValue<PathValue<TFieldValues, Path<TFieldValues>>>'.
  • src/logic/createFormControl.ts#L617
• error TS2322: Type 'PathValue<TFieldValues, TName>' is not assignable to type 'UnpackNestedValue<PathValue<TFieldValues, TName>>'.
  • src/useController.ts#L97
• error TS2322: Type 'Partial<FieldArrayWithId<{ [x: string]: ...; }, TFieldArrayName, TKeyName>>[]' is not assignable to type 'Partial<FieldArrayWithId<TFieldValues, TFieldArrayName, TKeyName>>[]'.
  • src/useFieldArray.ts#L230
• error TS2322: Type 'Partial<FieldArrayWithId<FieldValues, TFieldArrayName, TKeyName>>[]' is not assignable to type 'Partial<FieldArrayWithId<TFieldValues, TFieldArrayName, TKeyName>>[]'.
  • src/useFieldArray.ts#L249

statelyai/xstate

5 of 17 projects failed to build with the old tsc

examples/template-svelte-ts/tsconfig.json

• error TS2307: Cannot find module './App.svelte' or its corresponding type declarations.
  • examples/template-svelte-ts/src/main.ts#L1

examples/todo-mvc-svelte/tsconfig.json

• error TS2307: Cannot find module './App.svelte' or its corresponding type declarations.
  • examples/todo-mvc-svelte/src/main.ts#L1

packages/xstate-inspect/tsconfig.json

• error TS2344: Type 'TSchema["states"][K]' does not satisfy the constraint 'Required<Pick<StateSchema<any>, "states">>'.
  • packages/core/src/types.ts#L170 in packages/core/tsconfig.json

packages/xstate-test/tsconfig.json

• error TS2344: Type 'TSchema["states"][K]' does not satisfy the constraint 'Required<Pick<StateSchema<any>, "states">>'.
  • packages/core/src/types.ts#L170 in packages/core/tsconfig.json

lensapp/lens

4 of 5 projects failed to build with the old tsc

tsconfig.json

• error TS7023: 'steps' implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.
  • src/renderer/components/wizard/wizard.tsx#L55
• error TS7006: Parameter 'stepElem' implicitly has an 'any' type.
  • src/renderer/components/wizard/wizard.tsx#L105

[andrewbranch]

The lens issue is new. The error almost looks correct, except that this assertion is intended to silence it. In 4.4, if you remove the type assertion, you get the same error. In main, the assertion doesn’t silence the error even though it seems like it possibly could or should. This is worth investigating, but should be easy to work around, so I don’t think it’s a major issue for 4.5.

[andrewbranch]

Self-contained repro:

export class Wizard {

  get steps() {
    const steps = undefined! as { props: { wizard?: Wizard } }[];

    return steps.map(step => {
      const stepProps = step.props;

      return {
        wizard: this,
        ...stepProps,
      } as { wizard?: Wizard };
    });
  }
}

[andrewbranch]

Also, the issue isn’t currently in release-4.5, so this is something to investigate for 4.6.

[rbuckton]

The lens issue was already detected in #46939 as a result of #45729. It looks like @RyanCavanaugh was looking into a solution, but also submitted an upstream fix to lens in lensapp/lens#4480.

[RyanCavanaugh]

Probably then fixed in #46981