Don't include completions for current and later parameters

[zardoy]

Tried to find oldest completion issue :)

Fixes #1858

[DanielRosenwasser]

The test file should be renamed:

tests/cases/fourslash/noIncorrectParamaterCompletions.ts
tests/cases/fourslash/noCompletionsForCurrentOrLaterParameters.ts

[DanielRosenwasser]

Can you just switch the helper function to just be getVariableOrParameterDeclaration and make decisions based on that?

[zardoy]

So your decision is to unify variableDeclaration and parameterDeclaration?

eg

const variableOrParameterDeclaration = getVariableOrParameterDeclaration(location, contextToken)

But what about this case then?:

const foo = (a = foo/*no foo suggestion*/) => {
    console.log(foo)
}

[zardoy]

BTW its fully valid location for foo suggestion, so maybe you're right

[zardoy]

I switched to getVariableOrParameterDeclaration(contextToken: Node | undefined). I'm using only contextToken to fit logic in single findAncestor. I don't really the idea of dropping location as I feel it can introduce a lot of breakage, though I'll look at tests and try to fix them

[zardoy]

BTW its fully valid location for foo suggestion, so maybe you're right

FYI

TypeScript/tests/cases/fourslash/completionListWithoutVariableinitializer.ts

Line 50 in 0791bb0

excludes: ["fn"],

[DanielRosenwasser]

I wonder if you could just get await with using the node positions.

Suggested change

	// Filter out parameters from their own initializers
	// `function f(a = /* no 'a' here */) { }`
	if (symbol.valueDeclaration === parameterDeclaration) {
	return false;
	}
	// Filter out parameters from other parameters' initializers
	// `function f(a = /* no 'b' here */, b) { }`
	const parameters = parameterDeclaration.parent.parameters;
	const currentParamIdx = parameters.indexOf(parameterDeclaration);
	if (parameters.slice(currentParamIdx).some((p) => symbol.valueDeclaration === p)) {
	return false;
	}
	const declarationPos = symbol.valueDeclaration.pos;
	if (parameterDeclaration.pos <= declarationPos && declarationPos < parameters.end) {
	return false;
	}

[zardoy]

Seems to be good idea! but I still wonder why do we need declarationPos < parameters.end check?

[zardoy]

Didn't expect so many failing tests 😅 , will look again at them in a few days

[zardoy]

It seems using contextToken in new implementation improved quality in some test cases, I'm happy with result

[zardoy]

Also I have a quick question. Speaking of getVariableOrParameterDeclaration I wonder wether the logic can be extracted for codefixes in future. Just for motivation consider this issue:

let fileName

const foo = (displayName = fileNam/*<-*/, fileName2) => {
    // ERROR: Cannot find name 'fileNam'. Did you mean 'fileName2'?

    // super annoying sometimes, would be cool if codefixes were smarter
}

[zardoy]

@DanielRosenwasser I'm sorry to bother you, but I wanted to do the same for type parameters. Would it be better to do it in this PR or create another one after its get merged? Its just a matter of adding an extra check 😉.

[jakebailey]

I'm sorry to bother you, but I wanted to do the same for type parameters. Would it be better to do it in this PR or create another one after its get merged? Its just a matter of adding an extra check 😉.

How simple are we talking? If it's not too bad, I don't think it's a big deal to include it here.

[zardoy]

How simple are we talking? If it's not too bad, I don't think it's a big deal to include it here.

Okay, I think it's done

[sandersn]

Very nice and small change. I had some questions and suggestions.

[zardoy]

I see it's in waiting on author. Is anything else required here from my side?

[sandersn]

I was waiting on a review from @DanielRosenwasser since he previously requested changes.