377 lines
9.9 KiB
C++
377 lines
9.9 KiB
C++
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
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#pragma once
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#include <unordered_set>
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#include "Luau/DenseHash.h"
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#include "Luau/RecursionCounter.h"
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#include "Luau/TypePack.h"
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#include "Luau/TypeVar.h"
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LUAU_FASTINT(LuauVisitRecursionLimit)
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LUAU_FASTFLAG(LuauNormalizeFlagIsConservative)
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LUAU_FASTFLAG(LuauCompleteVisitor);
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namespace Luau
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{
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namespace visit_detail
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{
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/**
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* Apply f(tid, t, seen) if doing so would pass type checking, else apply f(tid, t)
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*
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* We do this to permit (but not require) TypeVar visitors to accept the seen set as an argument.
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*/
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template<typename F, typename A, typename B, typename C>
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auto apply(A tid, const B& t, C& c, F& f) -> decltype(f(tid, t, c))
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{
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return f(tid, t, c);
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}
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template<typename A, typename B, typename C, typename F>
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auto apply(A tid, const B& t, C&, F& f) -> decltype(f(tid, t))
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{
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return f(tid, t);
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}
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inline bool hasSeen(std::unordered_set<void*>& seen, const void* tv)
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{
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void* ttv = const_cast<void*>(tv);
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return !seen.insert(ttv).second;
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}
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inline bool hasSeen(DenseHashSet<void*>& seen, const void* tv)
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{
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void* ttv = const_cast<void*>(tv);
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if (seen.contains(ttv))
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return true;
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seen.insert(ttv);
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return false;
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}
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inline void unsee(std::unordered_set<void*>& seen, const void* tv)
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{
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void* ttv = const_cast<void*>(tv);
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seen.erase(ttv);
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}
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inline void unsee(DenseHashSet<void*>& seen, const void* tv)
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{
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// When DenseHashSet is used for 'visitTypeVarOnce', where don't forget visited elements
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}
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} // namespace visit_detail
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template<typename S>
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struct GenericTypeVarVisitor
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{
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using Set = S;
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Set seen;
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int recursionCounter = 0;
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GenericTypeVarVisitor() = default;
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explicit GenericTypeVarVisitor(Set seen)
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: seen(std::move(seen))
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{
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}
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virtual void cycle(TypeId) {}
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virtual void cycle(TypePackId) {}
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virtual bool visit(TypeId ty)
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{
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return true;
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}
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virtual bool visit(TypeId ty, const BoundTypeVar& btv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const FreeTypeVar& ftv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const GenericTypeVar& gtv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const ErrorTypeVar& etv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const ConstrainedTypeVar& ctv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const PrimitiveTypeVar& ptv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const FunctionTypeVar& ftv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const TableTypeVar& ttv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const MetatableTypeVar& mtv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const ClassTypeVar& ctv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const AnyTypeVar& atv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const UnknownTypeVar& utv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const NeverTypeVar& ntv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const UnionTypeVar& utv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const IntersectionTypeVar& itv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const BlockedTypeVar& btv)
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{
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return visit(ty);
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}
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virtual bool visit(TypeId ty, const SingletonTypeVar& stv)
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{
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return visit(ty);
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}
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virtual bool visit(TypePackId tp)
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{
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return true;
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}
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virtual bool visit(TypePackId tp, const BoundTypePack& btp)
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{
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return visit(tp);
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}
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virtual bool visit(TypePackId tp, const FreeTypePack& ftp)
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{
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return visit(tp);
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}
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virtual bool visit(TypePackId tp, const GenericTypePack& gtp)
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{
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return visit(tp);
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}
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virtual bool visit(TypePackId tp, const Unifiable::Error& etp)
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{
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return visit(tp);
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}
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virtual bool visit(TypePackId tp, const TypePack& pack)
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{
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return visit(tp);
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}
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virtual bool visit(TypePackId tp, const VariadicTypePack& vtp)
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{
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return visit(tp);
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}
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void traverse(TypeId ty)
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{
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RecursionLimiter limiter{&recursionCounter, FInt::LuauVisitRecursionLimit};
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if (visit_detail::hasSeen(seen, ty))
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{
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cycle(ty);
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return;
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}
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if (auto btv = get<BoundTypeVar>(ty))
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{
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if (visit(ty, *btv))
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traverse(btv->boundTo);
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}
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else if (auto ftv = get<FreeTypeVar>(ty))
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visit(ty, *ftv);
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else if (auto gtv = get<GenericTypeVar>(ty))
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visit(ty, *gtv);
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else if (auto etv = get<ErrorTypeVar>(ty))
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visit(ty, *etv);
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else if (auto ctv = get<ConstrainedTypeVar>(ty))
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{
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if (visit(ty, *ctv))
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{
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for (TypeId part : ctv->parts)
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traverse(part);
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}
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}
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else if (auto ptv = get<PrimitiveTypeVar>(ty))
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visit(ty, *ptv);
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else if (auto ftv = get<FunctionTypeVar>(ty))
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{
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if (visit(ty, *ftv))
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{
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traverse(ftv->argTypes);
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traverse(ftv->retTypes);
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}
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}
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else if (auto ttv = get<TableTypeVar>(ty))
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{
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// Some visitors want to see bound tables, that's why we traverse the original type
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if (visit(ty, *ttv))
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{
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if (ttv->boundTo)
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{
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traverse(*ttv->boundTo);
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}
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else
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{
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for (auto& [_name, prop] : ttv->props)
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traverse(prop.type);
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if (ttv->indexer)
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{
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traverse(ttv->indexer->indexType);
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traverse(ttv->indexer->indexResultType);
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}
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}
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}
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}
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else if (auto mtv = get<MetatableTypeVar>(ty))
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{
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if (visit(ty, *mtv))
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{
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traverse(mtv->table);
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traverse(mtv->metatable);
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}
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}
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else if (auto ctv = get<ClassTypeVar>(ty))
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{
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if (visit(ty, *ctv))
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{
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for (const auto& [name, prop] : ctv->props)
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traverse(prop.type);
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if (ctv->parent)
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traverse(*ctv->parent);
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if (ctv->metatable)
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traverse(*ctv->metatable);
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}
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}
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else if (auto atv = get<AnyTypeVar>(ty))
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visit(ty, *atv);
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else if (auto utv = get<UnionTypeVar>(ty))
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{
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if (visit(ty, *utv))
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{
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for (TypeId optTy : utv->options)
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traverse(optTy);
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}
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}
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else if (auto itv = get<IntersectionTypeVar>(ty))
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{
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if (visit(ty, *itv))
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{
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for (TypeId partTy : itv->parts)
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traverse(partTy);
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}
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}
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else if (!FFlag::LuauCompleteVisitor)
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return visit_detail::unsee(seen, ty);
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else if (get<LazyTypeVar>(ty))
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{
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// Visiting into LazyTypeVar may necessarily cause infinite expansion, so we don't do that on purpose.
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// Asserting also makes no sense, because the type _will_ happen here, most likely as a property of some ClassTypeVar
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// that doesn't need to be expanded.
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}
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else if (auto stv = get<SingletonTypeVar>(ty))
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visit(ty, *stv);
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else if (auto btv = get<BlockedTypeVar>(ty))
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visit(ty, *btv);
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else if (auto utv = get<UnknownTypeVar>(ty))
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visit(ty, *utv);
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else if (auto ntv = get<NeverTypeVar>(ty))
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visit(ty, *ntv);
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else
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LUAU_ASSERT(!"GenericTypeVarVisitor::traverse(TypeId) is not exhaustive!");
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visit_detail::unsee(seen, ty);
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}
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void traverse(TypePackId tp)
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{
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if (visit_detail::hasSeen(seen, tp))
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{
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cycle(tp);
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return;
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}
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if (auto btv = get<BoundTypePack>(tp))
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{
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if (visit(tp, *btv))
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traverse(btv->boundTo);
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}
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else if (auto ftv = get<Unifiable::Free>(tp))
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visit(tp, *ftv);
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else if (auto gtv = get<Unifiable::Generic>(tp))
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visit(tp, *gtv);
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else if (auto etv = get<Unifiable::Error>(tp))
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visit(tp, *etv);
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else if (auto pack = get<TypePack>(tp))
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{
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bool res = visit(tp, *pack);
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if (!FFlag::LuauNormalizeFlagIsConservative || res)
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{
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for (TypeId ty : pack->head)
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traverse(ty);
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if (pack->tail)
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traverse(*pack->tail);
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}
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}
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else if (auto pack = get<VariadicTypePack>(tp))
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{
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bool res = visit(tp, *pack);
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if (!FFlag::LuauNormalizeFlagIsConservative || res)
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traverse(pack->ty);
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}
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else
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LUAU_ASSERT(!"GenericTypeVarVisitor::traverse(TypePackId) is not exhaustive!");
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visit_detail::unsee(seen, tp);
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}
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};
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/** Visit each type under a given type. Skips over cycles and keeps recursion depth under control.
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*
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* The same type may be visited multiple times if there are multiple distinct paths to it. If this is undesirable, use
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* TypeVarOnceVisitor.
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*/
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struct TypeVarVisitor : GenericTypeVarVisitor<std::unordered_set<void*>>
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{
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};
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/// Visit each type under a given type. Each type will only be checked once even if there are multiple paths to it.
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struct TypeVarOnceVisitor : GenericTypeVarVisitor<DenseHashSet<void*>>
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{
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TypeVarOnceVisitor()
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: GenericTypeVarVisitor{DenseHashSet<void*>{nullptr}}
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{
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}
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};
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} // namespace Luau
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