mirror of
https://github.com/nim-lang/Nim.git
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49 lines
1.2 KiB
Nim
49 lines
1.2 KiB
Nim
discard """
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output: '''@[1, 2, 3]
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@[4.0, 5.0, 6.0]
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@[1, 2, 3]
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@[4.0, 5.0, 6.0]
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@[1, 2, 3]
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@[4, 5, 6]'''
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"""
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# bug #3476
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proc foo[T]: var seq[T] =
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## Problem! Bug with generics makes every call to this proc generate
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## a new seq[T] instead of retrieving the `items {.global.}` variable.
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var items {.global.}: seq[T]
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return items
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proc foo2[T]: ptr seq[T] =
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## Workaround! By returning by `ptr` instead of `var` we can get access to
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## the `items` variable, but that means we have to explicitly deref at callsite.
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var items {.global.}: seq[T]
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return addr items
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proc bar[T]: var seq[int] =
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## Proof. This proc correctly retrieves the `items` variable. Notice the only thing
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## that's changed from `foo` is that it returns `seq[int]` instead of `seq[T]`.
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var items {.global.}: seq[int]
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return items
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foo[int]() = @[1, 2, 3]
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foo[float]() = @[4.0, 5.0, 6.0]
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foo2[int]()[] = @[1, 2, 3]
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foo2[float]()[] = @[4.0, 5.0, 6.0]
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bar[int]() = @[1, 2, 3]
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bar[float]() = @[4, 5, 6]
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echo foo[int]() # prints 'nil' - BUG!
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echo foo[float]() # prints 'nil' - BUG!
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echo foo2[int]()[] # prints '@[1, 2, 3]'
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echo foo2[float]()[] # prints '@[4.0, 5.0, 6.0]'
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echo bar[int]() # prints '@[1, 2, 3]'
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echo bar[float]() # prints '@[4, 5, 6]'
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