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8b73c98286
The above referenced issue was causing a compiler crash when writing differentiable protocols and corresponding implementers, without importing the `_Differentiation` module. Changes in this CR fix the issue by marking any `@differentiable` attributes as invalid, if the `_Differentiation` module has not been imported. This ignores the `@differentiable` attributes when the protocol witnesses are being verified. Witness verification was previously leading to an error (due to missing `@differentiable` attribute on the protocol requirement implementer), and the corresponding diagnostic emission code was then leading to a crash, because it was expecting the `_Differentiation` module to be present.
17 lines
656 B
Swift
17 lines
656 B
Swift
// RUN: %target-typecheck-verify-swift
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protocol P {
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@differentiable(reverse) // expected-error {{@differentiable attribute used without importing module '_Differentiation'}}
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func req()
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}
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struct S: P {
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// Had the `_Differentiation` module been imported, this conformance
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// requirement would have generated an error, complaining about the
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// missing `@derivative` attribute. However, because the `_Differentiation`
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// module import is missing, the `@differential` attribute on `P` is marked
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// invalid and therefore not used while validating witnesses (specifically `S.req()`)
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// for the `P.req()` requirement.
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public func req() {}
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}
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