3acd77a154
Floris van Doorn [reported on Zulip](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/have.20tactic.20error.20recovery/near/425283053) that it is confusing that the `have : T := e` tactic completely fails if the body `e` is not of type `T`. This is in contrast to `have : T := by exact e`, which does not completely fail when `e` is not of type `T`. This ends up being caused by `elabTermEnsuringType` throwing an error when it fails to insert a coercion. Now, it detects this case, and it checks the `errToSorry` flag to decide whether to throw the error or to log the error and insert a `sorry`. This is justified by `elabTermEnsuringType` being a frontend to `elabTerm`, which inserts `sorry` on error. An alternative would be to make `ensureType` respect `errToSorry`, but there exists code that expects being able to catch when `ensureType` fails. Making such code manipulate `errToSorry` seems error prone, and this function is not a main entry point to the term elaborator, unlike `elabTermEnsuringType`.
22 lines
1.1 KiB
Text
22 lines
1.1 KiB
Text
issue2260.lean:8:20-8:21: error: The termination argument depends on the function's varying parameters. Try using `sizeOf` explicitly:
|
|
The termination argument has type
|
|
DNat i : Type
|
|
but is expected to have type
|
|
?β : Sort ?u
|
|
issue2260.lean:15:20-15:21: error: The termination argument types differ for the different functions, or depend on the function's varying parameters. Try using `sizeOf` explicitly:
|
|
The termination argument has type
|
|
DNat i : Type
|
|
but is expected to have type
|
|
?β : Sort ?u
|
|
issue2260.lean:31:20-31:21: error: The termination argument types differ for the different functions, or depend on the function's varying parameters. Try using `sizeOf` explicitly:
|
|
The termination argument has type
|
|
DNat i : Type
|
|
but is expected to have type
|
|
Nat : Type
|
|
issue2260.lean:26:15-26:21: error: failed to prove termination, possible solutions:
|
|
- Use `have`-expressions to prove the remaining goals
|
|
- Use `termination_by` to specify a different well-founded relation
|
|
- Use `decreasing_by` to specify your own tactic for discharging this kind of goal
|
|
n✝ : Nat
|
|
n : DNat n✝
|
|
⊢ sorryAx Nat true < 1 + n✝ + sizeOf n
|