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fixes #21753 [backport] (#21802)

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This commit is contained in:
Andreas Rumpf
2023-05-06 21:25:45 +02:00
committed by GitHub
parent 365a753eed
commit d0c62fa169
1 changed files with 6 additions and 3 deletions
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9
compiler/types.nim
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@@ -396,9 +396,9 @@ proc canFormAcycleAux(marker: var IntSet, typ: PType, startId: int): bool =
result = true
elif not containsOrIncl(marker, t.id):
for i in 0..<t.len:
result = canFormAcycleAux(marker, t[i], startId)
result = canFormAcycleAux(marker, t[i], abs startId)
if result: return
if t.n != nil: result = canFormAcycleNode(marker, t.n, startId)
if t.n != nil: result = canFormAcycleNode(marker, t.n, abs startId)
# Inheritance can introduce cyclic types, however this is not relevant
# as the type that is passed to 'new' is statically known!
# er but we use it also for the write barrier ...
@@ -415,7 +415,10 @@ proc isFinal*(t: PType): bool =
proc canFormAcycle*(typ: PType): bool =
var marker = initIntSet()
let t = skipTypes(typ, abstractInst+{tyOwned}-{tyTypeDesc})
result = canFormAcycleAux(marker, t, t.id)
# startId begins with a negative value that is only in the first recursion
# and the following recursions set to its real value. This fixes
# bug #21753:
result = canFormAcycleAux(marker, t, -t.id)
proc mutateTypeAux(marker: var IntSet, t: PType, iter: TTypeMutator,
closure: RootRef): PType