luau/Analysis/include/Luau/Unifier2.h
Andy Friesen 31a017c5c7
Sync to upstream/release/595 (#1044)
* Rerun clang-format on the code
* Fix the variance on indexer result subtyping. This fixes some issues
with inconsistent error reporting.
* Fix a bug in the normalization logic for intersections of strings

New Type Solver

* New overload selection logic
* Subtype tests now correctly treat a generic as its upper bound within
that generic's scope
* Semantic subtyping for negation types
* Semantic subtyping between strings and compatible table types like
`{lower: (string) -> string}`
* Further work toward finalizing our new subtype test
* Correctly generalize module-scope symbols

Native Codegen

* Lowering statistics for assembly
* Make executable allocation size/limit configurable without a rebuild.
Use `FInt::LuauCodeGenBlockSize` and `FInt::LuauCodeGenMaxTotalSize`.

---------

Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
2023-09-15 10:26:59 -07:00

75 lines
2 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#pragma once
#include "Luau/DenseHash.h"
#include "Luau/NotNull.h"
#include <optional>
#include <vector>
#include <utility>
namespace Luau
{
using TypeId = const struct Type*;
using TypePackId = const struct TypePackVar*;
struct BuiltinTypes;
struct InternalErrorReporter;
struct Scope;
struct TypeArena;
enum class OccursCheckResult
{
Pass,
Fail
};
struct Unifier2
{
NotNull<TypeArena> arena;
NotNull<BuiltinTypes> builtinTypes;
NotNull<InternalErrorReporter> ice;
int recursionCount = 0;
int recursionLimit = 0;
Unifier2(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, NotNull<InternalErrorReporter> ice);
/** Attempt to commit the subtype relation subTy <: superTy to the type
* graph.
*
* @returns true if successful.
*
* Note that incoherent types can and will successfully be unified. We stop
* when we *cannot know* how to relate the provided types, not when doing so
* would narrow something down to never or broaden it to unknown.
*
* Presently, the only way unification can fail is if we attempt to bind one
* free TypePack to another and encounter an occurs check violation.
*/
bool unify(TypeId subTy, TypeId superTy);
// TODO think about this one carefully. We don't do unions or intersections of type packs
bool unify(TypePackId subTp, TypePackId superTp);
std::optional<TypeId> generalize(NotNull<Scope> scope, TypeId ty);
private:
/**
* @returns simplify(left | right)
*/
TypeId mkUnion(TypeId left, TypeId right);
/**
* @returns simplify(left & right)
*/
TypeId mkIntersection(TypeId left, TypeId right);
// Returns true if needle occurs within haystack already. ie if we bound
// needle to haystack, would a cyclic TypePack result?
OccursCheckResult occursCheck(DenseHashSet<TypePackId>& seen, TypePackId needle, TypePackId haystack);
};
} // namespace Luau