LowFile-scopeC# Plug & play

Check query results before accessing indices

Validate collection bounds and query results before indexing; prefer FirstOrDefault/SingleOrDefault with null checks.

Why this matters

Prevents IndexOutOfRangeException and null dereferences.

Side-by-side examples engineers can pattern-match during review.

Avoid

var first = rows[0];

Prefer

var first = rows.FirstOrDefault(); if (first is null) return NotFound();

Bad

var x = list[0];

Good

var x = list.FirstOrDefault(); if(x==null) return;

From the same buckets as this rule.

Critical
Avoid equality operators in loop termination conditions
Check if loops use equality operators (== or !=) in termination conditions. These can lead to infinite loops if the condition is never met exactly. Instead, use relational operators like < or > for safer loop termination.
error-handlingreadability-refactor
Critical
Avoid Returning Null in Non-Async Task Methods
Returning null from a Task or Task<T> method causes a NullReferenceException if awaited. Use Task.CompletedTask or Task.FromResult<T>(null) instead.
error-handlingreadability-refactor+1
Critical
Avoid Using Boolean Expressions in `except` Statements
Detect `except` clauses that use `or` or `and` to catch multiple exceptions. This does not work as intended. Recommend using a tuple of exceptions instead.
error-handlingstack-python