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cleanup of in/out covariance handling

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This commit is contained in:
Andreas Rumpf 2017-05-17 20:54:53 +02:00
commit 7a95c961a7
6 changed files with 32 additions and 37 deletions
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18
compiler/semstmts.nim
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@ -758,7 +758,7 @@ proc checkCovariantParamsUsages(genericType: PType) =
case t.kind
of tyGenericParam:
t.sym.flags.incl sfWeakCovariant
t.flags.incl tfWeakCovariant
return true
of tyObject:
@ -783,17 +783,17 @@ proc checkCovariantParamsUsages(genericType: PType) =
for i in 1 .. <t.len:
let param = t[i]
if param.kind == tyGenericParam:
if sfCovariant in param.sym.flags:
let formalFlags = targetBody[i-1].sym.flags
if sfCovariant notin formalFlags:
if tfCovariant in param.flags:
let formalFlags = targetBody[i-1].flags
if tfCovariant notin formalFlags:
error("covariant param '" & param.sym.name.s &
"' used in a non-covariant position")
elif sfWeakCovariant in formalFlags:
param.sym.flags.incl sfWeakCovariant
elif tfWeakCovariant in formalFlags:
param.flags.incl tfWeakCovariant
result = true
elif sfContravariant in param.sym.flags:
elif tfContravariant in param.flags:
let formalParam = targetBody[i-1].sym
if sfContravariant notin formalParam.flags:
if tfContravariant notin formalParam.typ.flags:
error("contravariant param '" & param.sym.name.s &
"' used in a non-contravariant position")
result = true
@ -865,7 +865,7 @@ proc typeSectionRightSidePass(c: PContext, n: PNode) =
body.sym = s
body.size = -1 # could not be computed properly
s.typ.sons[sonsLen(s.typ) - 1] = body
if sfCovariant in s.flags:
if tfCovariant in s.typ.flags:
checkCovariantParamsUsages(s.typ)
# XXX: This is a temporary limitation:
# The codegen currently produces various failures with