1659f3bfe2
In patterns, ellipsis should always fill in each remaining argument as an implicit argument, even if it is an optparam or autoparam. This prevents examples such as the one in #4555 from failing: ```lean match e with | .internal .. => sorry | .error .. => sorry ``` The `internal` constructor has an optparam (`| internal (id : InternalExceptionId) (extra : KVMap := {})`). We may consider having ellipsis suppress optparams and autoparams in general. We avoid doing so for now since it's possible to opt-out of them individually (for example with `.internal (extra := _) ..`) but it's not possible to opt-in, and it is plausible that `..` with optparams is useful in contexts such as the `refine` tactic. With patterns however, it is hard to imagine a use case that offsets the inconvenience of optparams being eagerly supplied. Closes #4555
16 lines
332 B
Text
16 lines
332 B
Text
import Lean.Exception
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/-!
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# In pattern, `..` shouldn't make use of opt-params
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https://github.com/leanprover/lean4/issues/4555
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-/
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open Lean
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/-!
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The `.internal` constructor has an opt-param, which caused this to be a non-exhaustive match.
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-/
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example (e : Exception) : Nat :=
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match e with
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| .internal .. => 0
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| .error .. => 1
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