copy operands in Bytes.Add to avoid aliasing the receiver#1381
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Bytes values are immutable, but Add grew the receiver with append. When the receiver's backing array had spare capacity the second operand was written into it and the returned slice aliased the receiver, so two concatenations sharing a receiver corrupted each other. Allocate a fresh slice and copy both operands, matching list concatenation.
TristonianJones
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Jul 23, 2026
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Aliased backing array in Bytes.Add
Bytes.Addgrows the receiver withappend, so when a bound bytes value's backing array has spare capacity the second operand is written into that capacity and the result aliases the receiver rather than being a fresh copy. Evaluating[b + b"\x01", b + b"\x02"]against such a value returns[b+0x02, b+0x02]because the second concatenation overwrites the first. The concatenation now allocates its own slice sized to both operands, the same immutable-view guarantee list concatenation already provides.