7c809a94af
This PR avoids a `let` in the elaboration of `forIn`. It was introduced in https://github.com/leanprover/lean4/commit/f51328ff112 but nothing seems to break when I simplify the code. This removes an unexpected `let col✝ :=…` from the “Expected type” view in the Info View and from the termination proofs.
79 lines
1.6 KiB
Text
79 lines
1.6 KiB
Text
set_option pp.mvars.anonymous false
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/--
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error: failed to construct 'ForIn' instance for collection
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?_
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and monad
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Id
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-/
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#guard_msgs in
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example {c} := Id.run do
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for x in c do
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pure ()
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pure ()
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/--
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error: don't know how to synthesize implicit argument 'ρ'
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@forIn Id (List ?_) ?_ instForInOfForIn' PUnit Id.instMonad [] PUnit.unit fun x r => do
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pure ()
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pure (ForInStep.yield PUnit.unit)
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context:
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⊢ Type _
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---
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error: failed to infer binder type
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---
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error: don't know how to synthesize implicit argument 'α'
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@List.nil ?_
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context:
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⊢ Type _
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-/
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#guard_msgs in
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example : Unit := Id.run do
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for x in [] do
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pure ()
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pure ()
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/--
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error: failed to construct `ForIn'` instance for collection
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?_
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and monad
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Id
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-/
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#guard_msgs in
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example {c} := Id.run do
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for h : x in c do
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pure ()
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pure ()
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/--
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error: don't know how to synthesize implicit argument 'd'
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@forIn' Id (List ?_) ?_ inferInstance List.instForIn'InferInstanceMembership PUnit Id.instMonad [] PUnit.unit
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fun x h r => do
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pure ()
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pure (ForInStep.yield PUnit.unit)
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context:
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⊢ outParam (Membership ?_ (List ?_))
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---
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error: don't know how to synthesize implicit argument 'ρ'
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@forIn' Id (List ?_) ?_ inferInstance List.instForIn'InferInstanceMembership PUnit Id.instMonad [] PUnit.unit
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fun x h r => do
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pure ()
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pure (ForInStep.yield PUnit.unit)
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context:
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⊢ Type _
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---
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error: failed to infer binder type
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---
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error: failed to infer binder type
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---
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error: don't know how to synthesize implicit argument 'α'
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@List.nil ?_
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context:
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⊢ Type _
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-/
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#guard_msgs in
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example : Unit := Id.run do
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for h : x in [] do
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pure ()
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pure ()
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