A function where related statements are scattered with interleaved unrelated work — assignments to logically-coupled variables separated by lines that don't share their concern.
A function whose related statements are interleaved with unrelated work; the agent reasoning about any sub-step must track state across non-adjacent lines.
Related statements sit next to each other; the function reads as a sequence of cohesive sub-steps that are easy to extract.
Related statements sit next to each other; the agent reads the function as a sequence of cohesive blocks ready for extraction.
Before the refactoring
const basePrice = qty * itemPrice;logPriceCalc(basePrice);const tax = basePrice * 0.1;logTaxCalc(tax);
After the refactoring
const basePrice = qty * itemPrice;const tax = basePrice * 0.1;logPriceCalc(basePrice);logTaxCalc(tax);
Reader must hold partial sub-step state in working memory across unrelated statements; the implicit grouping inside the function stays implicit and obstructs further refactoring.
The agent holds partial sub-step state across non-adjacent lines; reasoning about any single concern requires tracking the others through the interleave.
Reordering can change behavior if statements aren't actually independent — verify side effects and dependencies before sliding.
Sliding can silently change behavior if statements aren't truly independent (hidden side effects, timing dependencies, observer effects); the agent verifying the slide must confirm independence at every gap.
Setup for Extract Function becomes trivial; the implicit grouping inside the function becomes explicit.
Statements that depend on one another sit next to each other; the agent reads each cluster as a unit without tracking state across non-adjacent lines to follow data flow.
Reordering statements without verifying independence — sliding past a statement with hidden side effects (logging that observes state, time-sensitive read) silently changes behavior.
Aggressive sliding without verifying side-effect ordering — observer logs, time reads, async dispatch — silently changes behavior the agent's local tests may not catch.