c06af84d9f
This PR resolves a defeq diamond, which caused a problem in Mathlib:
```
import Mathlib
example (R : Type) [I : Ring R] :
@AddCommGroup.toGrindIntModule R (@Ring.toAddCommGroup R I) =
@Lean.Grind.Ring.instIntModule R (@Ring.toGrindRing R I) := rfl -- fails
```
61 lines
824 B
Text
61 lines
824 B
Text
import Std
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/-!
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Ensure that we have not created lossy cast instances.
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-/
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/--
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error: type mismatch
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x
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has type
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Nat
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but is expected to have type
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Fin 8
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-/
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#guard_msgs in
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example (x : Nat) : Fin 8 := x
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/--
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error: type mismatch
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x
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has type
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Nat
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but is expected to have type
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UInt8
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-/
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#guard_msgs in
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example (x : Nat) : UInt8 := x
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/--
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error: type mismatch
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x
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has type
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Nat
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but is expected to have type
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USize
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-/
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#guard_msgs in
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example (x : Nat) : USize := x
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/--
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error: type mismatch
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x
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has type
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Nat
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but is expected to have type
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Int8
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-/
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#guard_msgs in
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example (x : Nat) : Int8 := x
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/--
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error: type mismatch
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x
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has type
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Nat
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but is expected to have type
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ISize
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-/
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#guard_msgs in
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example (x : Nat) : ISize := x
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-- TODO: currently there is a global lossy instance `NatCast (BitVec w)`, that should be removed.
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