a3cb98bb27
This PR fixes `inferControlInfoSeq` and `ControlInfo.sequence` to keep aggregating `breaks`/`continues`/`returnsEarly`/`reassigns` past elements whose `ControlInfo` reports `numRegularExits := 0`. Previously the analysis short-circuited at such elements, so any trailing `return`/`break`/`continue` was missing from the inferred info. The elaboration framework only skips subsequent doElems syntactically for top-level `return`/`break`/`continue`; for every other `numRegularExits == 0` case (e.g. a `match`/`if`/`try` whose branches all terminate, or a `repeat` without `break`) the elaborator keeps visiting the continuation and the for/match elaborator then tripped its invariant check with `Early returning ... but the info said there is no early return`. With this change the inferred info matches what the elaborator actually sees, which also removes the need for the `numRegularExits := 1` workaround on `repeat` introduced in #13479.
67 lines
1.9 KiB
Text
67 lines
1.9 KiB
Text
set_option backward.do.legacy false
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-- When an inner doElem's `ControlInfo` has `numRegularExits := 0` (because all branches
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-- `break`/`continue`/`return`, or it is a non-terminating `repeat`), the trailing `return`
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-- inside the enclosing `for` body used to be dropped during inference, and the for elaborator
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-- then threw "Early returning ... but the info said there is no early return" even though the
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-- elaborator does visit the trailing element. `ofSeq`/`ControlInfo.sequence` now aggregate
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-- `breaks`/`continues`/`returnsEarly`/`reassigns` past `numRegularExits == 0` elements, so the
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-- inferred info matches what the elaborator actually sees.
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/--
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warning: This `do` element and its control-flow region are dead code. Consider refactoring your code to remove it.
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-/
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#guard_msgs in
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example (cond : Bool) : IO Nat := do
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for _ in [1, 2] do
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if cond then break else break
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return 42
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return 1
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/--
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warning: This `do` element and its control-flow region are dead code. Consider refactoring your code to remove it.
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-/
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#guard_msgs in
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example (cond : Bool) : IO Nat := do
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for _ in [1, 2] do
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if cond then continue else continue
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return 42
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return 1
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#guard_msgs in
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example (i : Nat) : IO Nat := do
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for _ in [1, 2] do
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match i with
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| 0 => break
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| _ => break
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return 42
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return 1
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/--
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warning: This `do` element and its control-flow region are dead code. Consider refactoring your code to remove it.
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-/
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#guard_msgs in
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example : IO Nat := do
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for _ in [1, 2] do
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try break catch _ => break
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return 42
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return 1
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/--
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warning: This `do` element and its control-flow region are dead code. Consider refactoring your code to remove it.
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-/
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#guard_msgs in
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example (cond : Bool) : IO Nat := do
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for _ in [1, 2] do
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unless cond do break
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if cond then break else break
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return 42
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return 1
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#guard_msgs in
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example : IO Nat := do
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for _ in [1, 2] do
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repeat
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pure ()
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return 42
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return 1
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