c9239bfaa8
This is "upstreaming" mathlib's `unfold_let` tactic by incorporating its functionality into `unfold`. Now `unfold` can, in addition to unfolding global definitions, unfold local definitions. The PR also updates the `conv` version of the tactic. An improvement over `unfold_let` is that it beta reduces unfolded local functions. Two features not present in `unfold` are that (1) `unfold_let` with no arguments does zeta delta reduction of *all* local definitions, and also (2) `unfold_let` can interleave unfoldings (in contrast, `unfold a b c` is exactly the same as `unfold a; unfold b; unfold c`). Closes RFC #4090
95 lines
1.6 KiB
Text
95 lines
1.6 KiB
Text
/-!
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# Tests of the `unfold` tactic
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-/
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/-!
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Tests adapted from mathlib's `unfold_let` tactic
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-/
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example : let x := 1; let y := 2; x + y = y + x := by
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intro x y
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unfold x
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guard_target =ₛ 1 + y = y + 1
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let z := 3
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have h : z - 3 = 0 := rfl
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unfold z at h
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guard_hyp h :ₛ 3 - 3 = 0
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unfold y
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guard_target =ₛ 1 + 2 = 2 + 1
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rfl
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example : let x := 1; let y := 2; x + y = y + x := by
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intro x y
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unfold x y
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guard_target =ₛ 1 + 2 = 2 + 1
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rfl
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example : let x := 1; let y := 2 + x; y = 3 := by
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intro x y
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unfold y
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guard_target =ₛ 2 + x = 3
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unfold x
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guard_target =ₛ 2 + 1 = 3
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rfl
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example : let x := 1; let y := 2 + x; y = 3 := by
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intro x y
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fail_if_success unfold x y -- wrong order
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unfold y x
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guard_target =ₛ 2 + 1 = 3
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rfl
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/-!
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Do not reorder hypotheses. (`unfold` makes a change)
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-/
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set_option linter.unusedVariables false in
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example : let ty := Int; ty → Nat → Nat := by
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intro ty a a
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unfold ty at *
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exact a
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/-!
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Beta reduction of unfolded local functions
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-/
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example : True := by
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let f (x y : Nat) := x + y
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have : f 1 2 = 3 := by
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unfold f
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guard_target =ₛ 1 + 2 = 3
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rfl
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trivial
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/-!
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Nothing to unfold
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-/
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/--
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error: tactic 'unfold' failed to unfold 'id' at
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True
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-/
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#guard_msgs in
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example : True := by
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unfold id
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/--
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error: tactic 'unfold' failed to unfold 'x' at
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True
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-/
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#guard_msgs in
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example : True := by
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let x := 2
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unfold x
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/-!
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Conv tactic
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-/
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example (h : False) : id true = false := by
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conv => unfold id
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guard_target =ₛ true = false
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exact h.elim
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example : let x := 1; let y := 2; x + y = y + x := by
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intro x y
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conv => unfold x
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guard_target =ₛ 1 + y = y + 1
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rfl
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