Switch Default First Or Last

ID

go.switch_default_first_or_last

Severity

info

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Go

Tags

code-style

Description

Reports a switch whose default clause is placed somewhere other than first or last among the case clauses. Applies to both expression switches and type switches; select statements are not considered.

Rationale

The position of default does not change behaviour, but readers expect the catch-all either at the top (stated up front) or at the bottom (the fall-through of last resort). A default buried between ordinary cases is easy to overlook and reads like a normal case, which hurts comprehension and review.

switch n {
case 1:
    // ...
default:   // FLAW — neither first nor last
    // ...
case 2:
    // ...
}

Remediation

Move the default clause to the top or the bottom of the switch. Placing it last is the most common convention.

References