Add Type::spliceArray(), improve splice_array() array type narrowing

[herndlm]

Needs #3959 first

Closes phpstan/phpstan#11917

This is very similar to Type:: sliceArray() and it is used in NodeScopeResolver in a similar fashion as Type::popArray() is. Moving logic to Type deals obviously with all accessory types which were not working properly before too like e.g. list or non-empty-array.

First commit is a tiny refactor I didn't want to cause more noise and dependencies with another PR..

[staabm]

these operations look like they could be expressed on the type-level directly.

but as you said, maybe this would be too much and we leave it less abstract for now and see whether people report new issues

[herndlm]

Can we do such calculations too, can you show me an example maybe? I'm not too confident that I can make it work, but might be also a good follow-up.

[staabm]

maybe

phpstan-src/src/Type/Php/ArraySumFunctionDynamicReturnTypeExtension.php

Lines 36 to 56 in e6d9f0c

	if (count($argType->getConstantArrays()) > 0) {
	foreach ($argType->getConstantArrays() as $constantArray) {
	$node = new Int_(0);
	foreach ($constantArray->getValueTypes() as $i => $type) {
	if ($constantArray->isOptionalKey($i)) {
	$node = new Plus($node, new TypeExpr(TypeCombinator::union($type, new ConstantIntegerType(0))));
	} else {
	$node = new Plus($node, new TypeExpr($type));
	}
	}
	$resultTypes[] = $scope->getType($node);
	}
	} else {
	$itemType = $argType->getIterableValueType();
	$mulNode = new Mul(new TypeExpr($itemType), new TypeExpr(IntegerRangeType::fromInterval(0, null)));
	$resultTypes[] = $scope->getType(new Plus(new TypeExpr($itemType), $mulNode));
	}

or InitializerExprTypeResolver::get(Minus|Plus|...)Type

[herndlm]

can't figure out how to do this now unfortunately, there's also no access to scope in the type. but it's way simpler because non-optional keys don't have to be considered and there's a chance it might work somehow I suppose. maybe still a good follow-up :)

[phpstan-bot]

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[phpstan-bot]

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[herndlm]

the changes here confused me briefly, but it seems to be coming from loop generalization and there's not much I can do about it

[herndlm]

Meh, I'll do one more improvement and also add tests for the return types into the same file. Surely can't hurt and hopefully does not discover slice issues...

[herndlm]

Ok, so I figured out a way to get correct types for array_splice() without using getAllArrays(). But I had to use sliceArray() internally once to deal with the optional offsets.

[phpstan-bot]

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