checkers: rewrite deferUnlambda checker as a StmtListVisitor

[ehsundar]

• fix assigned closure function false-positive issue deferUnlambda: False positive for mutated variable #1401

[cristaloleg]

There are failures in make ci-linter

[ehsundar]

Addressed the issues.
Sorry for repetitive pushes. My IDE is configured to add and end line to every file including the generated one. I would change the code gen to add an empty line at the end in future...

[cristaloleg]

Sorry for the delay, I will take a look tomorrow. Thanks.

[cristaloleg]

SGTM

[quasilyte]

Based on the implementation, I guess it wouldn't "see" the assignment anywhere except the same depth level.

// This assignment inside of the if statement will not be handled.
if cond {
	foo = func() {
		println("should print")
	}
}

The proper analysis is cumbersome at AST level. This is probably one of the cases where SSA would be beneficial.

[ehsundar]

Thank you for your advice. Since this is the first time I work with AST, I'll see if I could figure out a proper solution based on what you mentioned.

[quasilyte]

It's better to check the "objects" for identity, so the shadowing doesn't break anything.
But for a single-level statement scanning name check is probably enough, depending on whether you want to make it recursive or not.

[ehsundar]

I've read a number of other checkers since last week and yet I couldn't find any similar situation to begin with. I also inspected the context using a debugger in which lays several utilities, however none of them helped me with the case. Could you possibly provide me with some reference, doc or code to help me find my way? Talking about accessing "objects" and utilizing SSA approach.

Of course there is always a way to implement something, but given that my little code is already messy and unreadable, I don't feel good about shooting in the dark.

[cristaloleg]

I will make a review today, thank you for the update.