trb/prefer-conditional-transfer

Prefer a conditional control-transfer statement when a simple if guard contains exactly one return, break, or next.

• Default: warning
• Recommended: yes
• First available: TypeRB 0.3.25
• Safe fix: yes, for the cases reported by the initial rule

Why

Guard clauses keep the main path at the surrounding indentation level. The conditional-transfer syntax expresses that shape directly without making trailing if a general modifier for calls or assignments.

Examples

The rule reports:

if cached != nil
	return cached
end

Use:

return cached if cached != nil

The same rule applies inside a loop:

next if item.hidden?()
break if complete

Fix boundary

The initial rule reports only a block that can be rewritten without moving or discarding comments, joining multiline expressions, or producing a line over 120 display columns. Tabs and Unicode display width are included. The edit replaces the complete if/end block, preserves the existing leading indentation, and retains the original transfer and condition text. More complex guards remain valid and are left unchanged.

The 120-column boundary is a conservative limit on when this rule may collapse a block into one line. It is not a general maximum line length for TypeRB source.

This rule does not report if with else or elsif, multiple body statements, value-producing if, or an already-authored conditional transfer.