ede1acfb44
This PR gives anonymous constructor notation (`⟨x,y⟩`) an error recovery mechanism where if there are not enough arguments then synthetic sorries are inserted for the missing arguments and an error is logged, rather than outright failing. Closes #9591.
51 lines
1.4 KiB
Text
51 lines
1.4 KiB
Text
/-!
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# Error recovery for anonymous constructor notation
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https://github.com/leanprover/lean4/issues/9591
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When errToSorry is enabled, and too few arguments are provided, now it inserts `sorry`s
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while logging an error (rather than throwing an error).
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-/
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/--
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error: Insufficient number of fields for `⟨...⟩` constructor: Constructor `Prod.mk` has 2 explicit field, but none were provided
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---
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info: have this := (sorry, sorry);
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this : Nat × Nat
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-/
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#guard_msgs in #check show Nat × Nat from ⟨⟩
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/--
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error: Insufficient number of fields for `⟨...⟩` constructor: Constructor `Prod.mk` has 2 explicit field, but only 1 was provided
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---
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info: have this := (2, sorry);
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this : Nat × Nat
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-/
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#guard_msgs in #check show Nat × Nat from ⟨2⟩
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/--
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error: Insufficient number of fields for `⟨...⟩` constructor: Constructor `Prod.mk` has 2 explicit field, but only 1 was provided
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---
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error: Unknown constant `Nat.su`
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Note: Inferred this name from the expected resulting type of `.su`:
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Nat
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---
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info: have this := (sorry, sorry);
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this : Nat × Nat
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-/
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#guard_msgs in #check show Nat × Nat from ⟨.su⟩
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/--
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info: have this := (2, 3);
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this : Nat × Nat
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-/
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#guard_msgs in #check show Nat × Nat from ⟨2,3⟩
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/-!
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The `first` tactic disables errToSorry, which is how the first `exact` throws an exception rather than logging an error.
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-/
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/--
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info: have this := (2, 3);
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this : Nat × Nat
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-/
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#guard_msgs in #check show Nat × Nat by first | exact ⟨1⟩ | exact ⟨2,3⟩
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