When printing s1, s2, then s3: It does exactly that, yes: https://go.dev/play/p/rs2FeK_QUjs https://go.dev/play/p/rs2FeK_QUjs [a b c] [a b c x] [a

When printing s1, s2, then s3: It does exactly that, yes: https://go.dev/play/p/rs2FeK_QUjs https://go.dev/play/p/rs2FeK_QUjs [a b c] [a b c x] [a b c y] But maybe it doesn't: https://go.dev/play/p/Na-eL0sOV9e https://go.dev/play/p/Na-eL0sOV9e [a b c] [a b c y] <- this is now "y" [a b c y] So... maybe they share the same backing array? Lets try setting s2[0] to "z" after appending with the original code: https://go.dev/play/p/mAB-gUb0shB https://go.dev/play/p/mAB-gUb0shB [a b c] [z b c x] [a b c y] Apparently not. But also apparently yes? https://go.dev/play/p/k1ciGzyS2gc https://go.dev/play/p/k1ciGzyS2gc [z b c] <- this changed too [z b c y] [z b c y] Let's try appending just one more item before redoing ^ that example, where they all shared the same data: https://go.dev/play/p/5JneXHMeUjx https://go.dev/play/p/5JneXHMeUjx [a b c] [z b c x x2] [a b c y y2] Notice that in all of these examples, I haven't explicitly declared a length or capacity. There's nothing "funny looking" or clearly intentionally allowing these different behaviors, it's just simple, very-common slice use. .... so yeah. This is a source of a number of hard-to-track-down bugs.