8d3be96024
A pending tactic mvar managed to escape into an unexpected context in
specific circumstances.
```lean
example : True := by
· rw [show 0 = 0 by rfl]
```
* Term elaboration of the `show` creates a pending mvar for the `by rfl`
proof
* `rw` fails with an exception because the pattern does not occur in the
target
* `cdot` catches the exception and admits the goal
* `Term.runTactic` [synthesizes all pending mvars from the tactic's
execution](5f9dedfe5e/src/Lean/Elab/SyntheticMVars.lean (L350)),
including the `by rfl` proof. But this would not have happened without
`cdot` as the exception would have skipped that invocation!
* Now incrementality is confused because the nested `by rfl` proof is
unexpectedly run in the same context as the top-level proof, writing to
the wrong promise, and the error message is lost
Solution: disable incrementality for these pending mvars
82 lines
2.1 KiB
Text
82 lines
2.1 KiB
Text
/-! Basic incremental reuse in top-level tactic block -/
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-- set_option trace.Elab.reuse true
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def basic : True := by
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dbg_trace "b 0"
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apply id
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dbg_trace "b 1"
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apply id
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dbg_trace "b 2"
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--^ sync
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--^ insert: ".5"
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/-!
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Ideally trailing whitespace should be ignored. CURRENTLY NOT WORKING as we use `Syntax.eqWithInfo`;
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we will need to patch old syntax info stored in the info tree to go back to `Syntax.structRangeEq`.
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-/
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-- RESET
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def trailingWhitespace : True := by
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dbg_trace "t 0"
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dbg_trace "t 1"
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dbg_trace "t 2"
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--^ sync
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--^ insert: "\n "
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-- RESET
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-- this used to restore the wrong elab state because of input context mis-tracking
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def haveBug : True := by
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have (a : Nat) : Nat → True := by
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intro n m
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--^ sync
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--^ delete: "intro n m"
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--^ sync
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--^ insert: "intro n m"
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--^ collectDiagnostics
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exact m
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/-! incremental reporting should obey `showPartialSyntaxErrors` -/
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-- RESET
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def partialSyntax : True := by apply (
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--^ collectDiagnostics
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/-! A tactic block not supported by incrementality should not accidentally swallow messages. -/
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-- RESET
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def otherMessage : Nat × Nat where
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fst := no
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snd := by skip
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--^ collectDiagnostics
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/-! Starting to type a comment should not invalidate the state above it. -/
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-- RESET
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def strayToken : True := by
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dbg_trace "s"
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unfold f
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--^ sync
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--^ insert: " -"
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/-!
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Insufficient reuse checking of trailing whitespace info in the info tree led to the goal view
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showing multiple tactics as they all claimed to be at the end of the file (which they were in prior
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versions).
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-/
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-- RESET
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def dup_goals : True := by
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show True
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--^ sync
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--^ insert: "show True\n show True\n show True\n show True\n "
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--^ sync
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--^ goals
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-- (note that request positions are computed relative to the original document, so the checks above
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-- will point at a `show` at run time)
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/-!
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A tactic mvar may sometimes escape the term elaboration it was created from and should not break
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incremental reporting in this case.
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-/
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-- RESET
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def tacInTermInTac : True := by
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· rw [show 0 = 0 by rfl]
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--^ collectDiagnostics
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