Andrew Trick cc07b4ba11 Fix LifetimeDependenceDiagnostics for @out dependencies. ...

Record a forwarding mark_dependence as a local access. This is necessary because
we now emit a mark_dependence for @out arguments, which will be the starting
point for diagnostics:

  %out = alloc_stack
  apply %f(%owned, %out) : $(Owner) -> @lifetime(borrow 0) @out View
  %unused = mark_dependence [unresolved] %out on %owner
  %dependentValue = load %out

This mark_dependence has no uses. Instead, it simply records the dependency of
the in-memory value on the owner. Consequently, simply walking the uses of
LifetimeDependence.dependentValue does fails to diagnose any escapes. Instead,
if the dependentValue is an address-type mark_dependence, treat it as a local
access to the address that it forwards. Then we find any reachable uses of that
local variable as a potential escape.

Fixes rdar://143040479
(Borrow diagnostics not triggered for @out return values)

2025-01-17 11:19:04 -08:00

32 KiB

Raw Permalink Blame History

View Raw