ba95dbc36b
This PR implements the `zetaUnused` simp and reduction option (added in #6754). True by default, and implied by `zeta`, this can be turned off to make simp even more careful about preserving the expression structure, including unused let and have expressions. Breaking change: The `split` tactic no longer removes unused let and have expressions as a side-effect, in rare cases this may break proofs. `dsimp only` can be used to remove unused have and let expressions.
80 lines
1.8 KiB
Text
80 lines
1.8 KiB
Text
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/--
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info: b : Bool
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⊢ if b = true then
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let_fun unused := ();
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True
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else False
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---
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warning: declaration uses 'sorry'
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-/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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trace_state; sorry
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/--
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info: b : Bool
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⊢ b = true
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---
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warning: declaration uses 'sorry'
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-/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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simp; trace_state; sorry
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/--
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info: b : Bool
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⊢ b = true ∧
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let_fun unused := ();
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True
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---
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warning: declaration uses 'sorry'
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-/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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simp (config := Lean.Meta.Simp.neutralConfig); trace_state; sorry
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/-- error: simp made no progress -/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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simp (config := Lean.Meta.Simp.neutralConfig) only; trace_state; sorry
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/--
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info: b : Bool
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⊢ if b = true then True else False
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---
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warning: declaration uses 'sorry'
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-/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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simp (config := Lean.Meta.Simp.neutralConfig) +zeta only; trace_state; sorry
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/--
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info: b : Bool
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⊢ if b = true then True else False
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---
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warning: declaration uses 'sorry'
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-/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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simp (config := Lean.Meta.Simp.neutralConfig) +zetaUnused only; trace_state; sorry
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-- Before the introduction of zetaUnused, split would do collateral damage to unused letFuns.
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-- Now they are preserved:
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/--
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info: case isTrue
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b : Bool
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h✝ : b = true
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⊢ let_fun unused := ();
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True
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---
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warning: declaration uses 'sorry'
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-/
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#guard_msgs in
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example (b : Bool) : if b then have unused := (); True else False := by
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split
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· trace_state; sorry
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· sorry
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