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18 lines
375 B
Nim
18 lines
375 B
Nim
# Covariance is not type safe:
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type
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TA = object of TObject
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a: int
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TB = object of TA
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b: array[0..5000_000, int]
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proc ap(x: var TA) = x.a = -1
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proc bp(x: var TB) = x.b[high(x.b)] = -1
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# in Nim proc (x: TB) is compatible to proc (x: TA),
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# but this is not type safe:
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var f = cast[proc (x: var TA) {.nimcall.}](bp)
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var a: TA
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f(a) # bp expects a TB, but gets a TA
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