ab606ba754
This PR provides an additional hint when the type of an autobound implicit is required to have function type or equality type — this fails, and the existing error message does not address the fact that the source of the error is an unknown identifier that was automatically bound. ## Example ``` import Lean example : MetaM String := pure "" ``` Current error message: ``` Function expected at MetaM but this term has type ?m Note: Expected a function because this term is being applied to the argument String ``` Additional error message provided by this PR: ``` Hint: The identifier `MetaM` is unknown, and Lean's `autoImplicit` option causes an unknown identifier to be treated as an implicitly bound variable with an unknown type. However, the unknown type cannot be a function, and a function is what Lean expects here. This is often the result of a typo or a missing `import` or `open` statement. ```
7 lines
452 B
Text
7 lines
452 B
Text
autoBoundPostponeLoop.lean:5:12-5:18: error: invalid `▸` notation, argument
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h
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has type
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?m
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equality expected
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Hint: The identifier `h` is unknown, and Lean's `autoImplicit` option causes an unknown identifier to be treated as an implicitly bound variable with an unknown type. However, the unknown type cannot be an equality, and an equality is what Lean expects here. This is often the result of a typo or a missing `import` or `open` statement.
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