feat: move nil check to call sites

[SoulPancake]

This addresses

// TODO(rbuckton): Move node != niltest to call sites
@rbuckton Can you please review this
I can undo the stylistic whitespace changes in the internal/ast/utilities.g
but I think they're for the better, LMK what you think

[SoulPancake]

@rbuckton Can you take a look at this?

[SaadiSave]

@SoulPancake Sorry for jumping on here for a slightly tangential issue, but I noticed that nil checks are inconsistent throughout the codebase. For example,

https://github.com/microsoft/typescript-go/blob/main/internal%2Fast%2Fast.go#L15-L31

type Visitor func(*Node) bool

func visit(v Visitor, node *Node) bool {
        if node != nil {
                return v(node)
        }
        return false
}

func visitNodes(v Visitor, nodes []*Node) bool {
        for _, node := range nodes {
                if v(node) {
                        return true
                }
        }
        return false
}

visit checks for nils, but the for loop doesn't check if node is nil. Do you have clear documentation on whether Visitors are supposed to handle nils? Because visit assumes they don't, and visitNodes assumes they do, which are mutually incompatible assumptions.

[SoulPancake]

@SaadiSave Agreed, I will add the nil check in the loop

[SaadiSave]

@SoulPancake is there a lint to enforce nil checks?

[SoulPancake]

Don't think so @SaadiSave

[jakebailey]

This PR has gotten out of date as main changed. Could you update it, or close it if you don't plan on working on this anymore?

[SoulPancake]

I will update it asap @jakebailey

[SoulPancake]

@jakebailey Done, Can you take a look at this?

[jakebailey]

I feel like most of these are redundant; I would think we'd only want ones that correspond to undefined checks in the original code.

[Copilot]

Pull Request Overview

This PR addresses a TODO comment by moving nil checks from the IsFunctionLike and IsFunctionLikeDeclaration utility functions to their call sites, improving code clarity and potentially performance by avoiding redundant nil checks.

Key changes:

• Removed internal nil checks from IsFunctionLike and IsFunctionLikeDeclaration functions
• Added explicit nil checks at all call sites where these functions are used
• Updated function documentation to clarify the nil check requirement

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal/ast/utilities.go	Removed nil checks from IsFunctionLike and IsFunctionLikeDeclaration, added documentation comments
internal/checker/checker.go	Added nil checks before calling IsFunctionLike and IsFunctionLikeDeclaration functions
internal/checker/grammarchecks.go	Added nil checks before calling IsFunctionLikeDeclaration and IsFunctionLike functions
internal/checker/flow.go	Added nil check before calling IsFunctionLike function
internal/binder/binder.go	Added nil check before calling IsFunctionLike function

[Copilot]

The nil check is only applied to the first condition in the OR expression. The call to ast.IsClassLike(parent) and other functions on subsequent lines also need nil checks for parent.

[Copilot]

The nil check is only applied to the first condition in the OR expression. The call to ast.IsAccessor(node.Parent) also needs a nil check for node.Parent.

Suggested change

	if !links.hasReportedStatementInAmbientContext && (node.Parent != nil && ast.IsFunctionLike(node.Parent) || ast.IsAccessor(node.Parent)) {
	if !links.hasReportedStatementInAmbientContext && node.Parent != nil && (ast.IsFunctionLike(node.Parent) || ast.IsAccessor(node.Parent)) {

[SoulPancake]

@jakebailey I guess these aren't needed or helpful as you mentioned, do you suggest I remove the TODO comments and remove the changes?

[SoulPancake]

Otherwise I am happy to close this PR @jakebailey