Use copy
ID |
go.use_copy |
Severity |
info |
Remediation Complexity |
trivial |
Remediation Risk |
low |
Remediation Effort |
low |
Resource |
Best Practice |
Language |
Go |
Tags |
best-practice, code-style |
Description
Reports a range loop whose entire body copies one slice into another element by element,
dst[i] = src[i].
Rationale
The builtin copy(dst, src) performs exactly this copy in a single bounds-checked call backed by
memmove, so it is both faster and clearer than the manual loop. The loop form also invites
off-by-one and wrong-variable mistakes that copy removes entirely. Loops that transform elements,
reverse the index, or do more than the plain copy are left untouched.
// Bad
for i := range src {
dst[i] = src[i]
}
// Good
copy(dst, src)Remediation
Replace the loop with copy(dst, src). Note that copy copies min(len(dst), len(src)) elements
and returns that count, which matches the loop’s behaviour when dst is sized to src.