9f4075be72
Recall that currently named arguments suppress all explicit parameters that are dependencies. This PR limits this feature to only apply to true structure projections, except in the case where it is triggered when there are no more positional arguments. This preserves the primary reason for generalizing this feature (issue #1851), while removing the generalized feature, which has led to numerous confusions (issue #1867). This also fixes a bug pointed out [on Zulip](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/.40foo.20.28A.20.3A.3D.20bar.29.20_.20_/near/468564862) where in `@` mode, instance implicit parameter dependencies to named arguments would be suppressed unless the next positional argument was `_`. More detail: * The `NamedArg` structure now has a `suppressDeps : Bool` field. It is set to `true` for the `self` argument in structure projections. If there is such a `NamedArg`, explicit parameters that are dependencies to the named argument are turned into implicit arguments. The consequence is that *all* structure projections are treated as if their type parameters are implicit, even for class projections. This flag is *not* used for generalized field notation. * We preserve the suppression feature when there are no positional arguments remaining. This feature pre-dates the fix to issue #1851, and it is useful when combining named arguments and the eta expansion feature, since dependencies of named arguments cannot be turned into eta arguments. Plus, there are examples of the form `rw [lem (h := foo)]` where `lem` has explicit arguments that `h` depends on. * For instance implicit parameters in explicit mode, now `_` arguments register terminfo and are hoverable. * Now `..` is respected in explicit mode. This implements RFC #5397. The `suppressDeps` flag suggests a future possibility of a named argument syntax that can suppress dependencies.
27 lines
588 B
Text
27 lines
588 B
Text
/-!
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# Tests for app elaborator in explicit mode
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-/
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namespace Test1
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/-!
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Named arguments in explicit mode cause arguments it depends on to become implicit.
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However, inst implicit arguments had odd behavior with `_`, since supplying `_` would override
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the fact that it should be implicit.
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-/
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theorem foo {p : Prop} [Decidable p] (h : ite p x y = x) : p := sorry
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variable {p : Prop} [Decidable p] {α : Type} (x y : α) (h : ite p x y = x)
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example : p := @foo (h := h)
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/--
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error: function expected at
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foo h
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term has type
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p
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-/
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#guard_msgs in
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example : p := @foo (h := h) _
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end Test1
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