Implement iter(), len() and is_empty() for all display-literal AST nodes

[AlexWaygood]

Summary

This PR adds iter(), len() and is_empty() methods to all the AST nodes representing "display literals":

• ExprList
• ExprSet
• ExprTuple
• ExprDict

Each of these nodes wraps an inner Vec of elements; it's rare to use these nodes in linter rules without either iterating over the elements or querying the number of elements. Exposing these methods on the outer nodes makes a lot of our code simpler and more elegant.

Test Plan

cargo test

[codspeed-hq]

CodSpeed Performance Report

Merging #12807 will not alter performance

_{Comparing AlexWaygood:alex/display-len (23b601e) with main (a99a458)}

Summary

✅ 32 untouched benchmarks

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

Formatter (stable)

ℹ️ ecosystem check encountered format errors. (no format changes; 1 project error)

openai/openai-cookbook (error)

warning: Detected debug build without --no-cache.
error: Failed to parse examples/Chat_finetuning_data_prep.ipynb:6:18:25: Unparenthesized generator expression cannot be used here
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_box.ipynb:13:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_confluence.ipynb:15:1:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_gmail.ipynb:15:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_jira.ipynb:15:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_notion.ipynb:15:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_sharepoint_doc.ipynb:28:1:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_sharepoint_text.ipynb:28:1:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_sql_database.ipynb:2:2:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_middleware_azure_function.ipynb:37:1:13: Simple statements must be separated by newlines or semicolons

Formatter (preview)

ℹ️ ecosystem check encountered format errors. (no format changes; 1 project error)

openai/openai-cookbook (error)

ruff format --preview

warning: Detected debug build without --no-cache.
error: Failed to parse examples/Chat_finetuning_data_prep.ipynb:6:18:25: Unparenthesized generator expression cannot be used here
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_box.ipynb:13:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_confluence.ipynb:15:1:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_gmail.ipynb:15:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_jira.ipynb:15:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_notion.ipynb:15:1:1: Expected an expression
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_sharepoint_doc.ipynb:28:1:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_sharepoint_text.ipynb:28:1:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_action_sql_database.ipynb:2:2:5: Simple statements must be separated by newlines or semicolons
error: Failed to parse examples/chatgpt/gpt_actions_library/gpt_middleware_azure_function.ipynb:37:1:13: Simple statements must be separated by newlines or semicolons

[dhruvmanila]

Each of these nodes wraps an inner Vec of elements; it's rare to use these nodes in linter rules without either iterating over the elements or querying the number of elements. Exposing these methods on the outer nodes makes a lot of our code simpler and more elegant.

If it makes sense, we could just implement Deref for these nodes that returns the inner Vec which would automatically expose all these methods (and other methods).

[AlexWaygood]

If it makes sense, we could just implement Deref for these nodes that returns the inner Vec which would automatically expose all these methods (and other methods).

Yeah, it's an interesting idea. I'm not sure if methods like dict.first() and dict.last() make as much sense as being able to iterate over the ExprDict node and directly query its length, though. I think I prefer to only implement a selection of methods that we know make sense.

I considered creating a DisplayLiteral trait for all of these nodes to implement, but in the end I concluded that it just created more complexity and didn't really simplify anything