43 lines
786 B
Text
43 lines
786 B
Text
structure A where
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x : Nat
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w : Nat
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structure B extends A where
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y : Nat
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structure C extends B where
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z : Nat
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def f1 (c : C) (a : A) : C :=
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{ c with toA := a, x := 0 } -- Error, `toA` and `x` are both updates to field `x`
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def f2 (c : C) (a : A) : C :=
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{ c with toA := a }
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def f3 (c : C) (a : A) : C :=
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{ a, c with x := 0 }
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theorem ex1 (a : A) (c : C) : (f3 c a).x = 0 :=
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rfl
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theorem ex2 (a : A) (c : C) : (f3 c a).w = a.w :=
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rfl
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def f4 (c : C) (a : A) : C :=
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{ c, a with x := 0 } -- TODO: generate error that `a` was not used?
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theorem ex3 (a : A) (c : C) : (f4 c a).w = c.w :=
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rfl
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theorem ex4 (a : A) (c : C) : (f4 c a).x = 0 :=
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rfl
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def f5 (c : C) (a : A) :=
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{ c, a with x := 0 }
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#check f5
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def f6 (c : C) (a : A) :=
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{ a, c with x := 0 }
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#check f6
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