Typescript development problem: Is specialized knowledge required to solve fourslash errors?

[craigphicks]

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I have a pull #56281 which involves changing src/lib/rs5.d.ts.
I think because it changes that file, there are a few fourslash errors similar to this one:

         fourslash tests
           tests/cases/fourslash/completionListInTypeParameterOfClassExpression1.ts
             fourslash test completionListInTypeParameterOfClassExpression1.ts runs correctly:
     AssertionError: At marker "4": expected [ 'D', 'any', 'Array', …(138) ] to deeply equal [ 'D', 'any', 'Array', …(137) ]
      at _TestState.verifyCompletionsAreExactly (src/harness/fourslashImpl.ts:1213:16)
      at _TestState.verifyCompletionsWorker (src/harness/fourslashImpl.ts:1074:18)
      at _TestState.verifyCompletions (src/harness/fourslashImpl.ts:1009:25)
      at Verify.completions (src/harness/fourslashInterfaceImpl.ts:251:31)
      at eval (completionListInTypeParameterOfClassExpression1.js:8:8)
      at runCode (src/harness/fourslashImpl.ts:4607:9)
      at runFourSlashTestContent (src/harness/fourslashImpl.ts:4565:5)
      at runFourSlashTest (src/harness/fourslashImpl.ts:4548:5)
      at Context.<anonymous> (src/testRunner/fourslashRunner.ts:60:39)
      at processImmediate (node:internal/timers:478:21)

They don't go away after hereby baseline-accept.
Does this require changing the LKG?
Otherwise, how to inspect the differences and modify the baseline?

[jakebailey]

If you read the test case, you'll see it mention globalTypesPlus, which depends on

TypeScript/src/harness/fourslashInterfaceImpl.ts

Line 1108 in 73bc0eb

const globalTypeDecls: readonly ExpectedCompletionEntryObject[] = [

and would need to be updated. Most (nearly all) PRs do not modify the globals in such a way that this hardcoded list changes.

[jakebailey]

However, needing to modify this may indicate that something is wrong with the PR (which I have not read; I am not sure anything has changed to make filter(Boolean) any more acceptable than before).

[craigphicks]

However, needing to modify this may indicate that something is wrong with the PR (which I have not read; I am not sure anything has changed to make filter(Boolean) any more acceptable than before).

I had added a BooleanConverter interface which has only the conversion with no constructor, to use as filter predicate. The idea being to be as specific as possible. However, based on your advice about the cost of changing globals, which I agree with, I have removed it now, and it is using BooleanConstructor without issue.

[typescript-bot]

This issue has been marked as "Question" and has seen no recent activity. It has been automatically closed for house-keeping purposes.