178ab8ef2e
Reported [on Zulip](https://leanprover.zulipchat.com/#narrow/stream/348111-std4/topic/Panics.20in.20Std.2EHashMap.2Efind!/near/406872395). The `dflt` argument of `Option.getD` is not evaluated lazily, as the documentation says, because even after `macro_inline` the expression ```lean match opt, dflt with | some x, _ => x | none, e => e ``` still has the semantics of evaluating `dflt` when `opt` is `some x`.
12 lines
307 B
Text
12 lines
307 B
Text
import Lean.Data.HashMap
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def test (m : Lean.HashMap Nat Nat) : IO (Nat × Nat) := do
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let start := 1
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let mut i := start
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let mut count := 0
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while i != 0 do
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i := (m.find? i).getD (panic! "key is not in the map")
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count := count + 1
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return (i, count)
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#eval test (.ofList [(1,3),(3,2),(2,0)])
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