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fix some issues overloading with generics and inheritance (#15211)

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* fix some issues overloading with generics and inheritance

* fix passing procs with subtype matches
This commit is contained in:
jcosborn 2020-08-27 05:56:38 -05:00 • committed by GitHub
commit d11933ad99
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2 changed files with 65 additions and 16 deletions
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45
compiler/sigmatch.nim
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@ -199,6 +199,27 @@ proc copyCandidate(a: var TCandidate, b: TCandidate) =
a.baseTypeMatch = b.baseTypeMatch
copyIdTable(a.bindings, b.bindings)
proc typeRel*(c: var TCandidate, f, aOrig: PType,
flags: TTypeRelFlags = {}): TTypeRelation
proc checkGeneric(a, b: TCandidate): int =
let c = a.c
let aa = a.callee
let bb = b.callee
var winner = 0
for i in 1..<min(aa.len, bb.len):
var ma = newCandidate(c, bb[i])
let tra = typeRel(ma, bb[i], aa[i], {trDontBind})
var mb = newCandidate(c, aa[i])
let trb = typeRel(mb, aa[i], bb[i], {trDontBind})
if tra == isGeneric and trb == isNone:
if winner == -1: return 0
winner = 1
if trb == isGeneric and tra == isNone:
if winner == 1: return 0
winner = -1
result = winner
proc sumGeneric(t: PType): int =
# count the "genericness" so that Foo[Foo[T]] has the value 3
# and Foo[T] has the value 2 so that we know Foo[Foo[T]] is more
@ -296,6 +317,9 @@ proc cmpCandidates*(a, b: TCandidate): int =
# the other way round because of other semantics:
result = b.inheritancePenalty - a.inheritancePenalty
if result != 0: return
# check for generic subclass relation
result = checkGeneric(a, b)
if result != 0: return
# prefer more specialized generic over more general generic:
result = complexDisambiguation(a.callee, b.callee)
# only as a last resort, consider scoping:
@ -336,9 +360,6 @@ proc describeArgs*(c: PContext, n: PNode, startIdx = 1;
result.add(argTypeToString(arg, prefer))
if i != n.len - 1: result.add(", ")
proc typeRel*(c: var TCandidate, f, aOrig: PType,
flags: TTypeRelFlags = {}): TTypeRelation
proc concreteType(c: TCandidate, t: PType; f: PType = nil): PType =
case t.kind
of tyTypeDesc:
@ -357,8 +378,7 @@ proc concreteType(c: TCandidate, t: PType; f: PType = nil): PType =
# proc sort[T](cmp: proc(a, b: T): int = cmp)
if result.kind != tyGenericParam: break
of tyGenericInvocation:
result = t
doAssert(false, "cannot resolve type: " & typeToString(t))
result = nil
of tyOwned:
# bug #11257: the comparison system.`==`[T: proc](x, y: T) works
# better without the 'owned' type:
@ -599,7 +619,8 @@ proc procParamTypeRel(c: var TCandidate, f, a: PType): TTypeRelation =
# if f is metatype.
result = typeRel(c, f, a)
if result <= isSubtype or inconsistentVarTypes(f, a):
# v--- is this correct?
if result <= isIntConv or inconsistentVarTypes(f, a):
result = isNone
#if result == isEqual:
@ -1465,7 +1486,7 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
if baseType != nil:
c.inheritancePenalty += 1
let ret = typeRel(c, f, baseType)
return if ret == isEqual: isSubtype else: ret
return if ret in {isEqual,isGeneric}: isSubtype else: ret
result = isNone
else:
@ -1496,10 +1517,12 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
#echo "inferred ", typeToString(inst), " for ", f
return typeRel(c, inst, a)
if x.kind == tyGenericInvocation or f[0].kind != tyGenericBody:
#InternalError("typeRel: tyGenericInvocation -> tyGenericInvocation")
# simply no match for now:
discard
if x.kind == tyGenericInvocation:
if f[0] == x[0]:
for i in 1..<f.len:
let tr = typeRel(c, f[i], x[i])
if tr <= isSubtype: return
result = isGeneric
elif x.kind == tyGenericInst and f[0] == x[0] and
x.len - 1 == f.len:
for i in 1..<f.len: