37 lines
686 B
Text
37 lines
686 B
Text
theorem CongrGood {x y: Nat}: x + y = y + x := by
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conv =>
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congr
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. rw [Nat.add_comm]
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. rfl
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theorem CongrBad {x y: Nat}: x + y = y + x := by
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have I: True := True.intro;
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conv =>
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congr
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. rw [Nat.add_comm]
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. rfl
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theorem CongrBad' {x y: Nat}: x + y = y + x := by
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let I: True := True.intro;
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conv =>
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congr
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. rw [Nat.add_comm]
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. rfl
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theorem CongrBad'' {x y: Nat}: x + y = y + x := by
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let I: True := True.intro;
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try rfl;
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conv =>
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congr
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. rw [Nat.add_comm]
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. rfl
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theorem CongrGood' {x y: Nat}: x + y = y + x := by
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cases x;
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have I: True := True.intro;
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rw [Nat.add_comm]
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conv =>
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congr
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. rw [Nat.add_comm]
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. rfl
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