luau/Analysis/src/TypeUtils.cpp
Arseny Kapoulkine f2e6a8f4a5
Sync to upstream/release/507-pre (#286)
This doesn't contain all changes for 507 yet but we might want to do the
Luau 0.507 release a bit earlier to end the year sooner.

Changes:

- Type ascription (::) now permits casts between related types in both directions, allowing to refine or loosen the type (RFC #56)
- Fix type definition for tonumber to return number? since the input string isn't guaranteed to contain a valid number
- Fix type refinements for field access via []
- Many stability fixes for type checker
- Provide extra information in error messages for type mismatches in more cases
- Improve performance of type checking for large unions when union members are string literals
- Add coverage reporting support to Repl (--coverage command line argument) and lua_getcoverage C API
- Work around code signing issues during Makefile builds on macOS
- Improve performance of truthiness checks in some cases, particularly on Apple M1, resulting in 10-25% perf gains on qsort benchmark depending on the CPU/compiler
- Fix support for little-endian systems; IBM s390x here we go!
2021-12-10 14:05:05 -08:00

79 lines
2.4 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#include "Luau/TypeUtils.h"
#include "Luau/Scope.h"
#include "Luau/ToString.h"
#include "Luau/TypeInfer.h"
namespace Luau
{
std::optional<TypeId> findMetatableEntry(ErrorVec& errors, const ScopePtr& globalScope, TypeId type, std::string entry, Location location)
{
type = follow(type);
std::optional<TypeId> metatable = getMetatable(type);
if (!metatable)
return std::nullopt;
TypeId unwrapped = follow(*metatable);
if (get<AnyTypeVar>(unwrapped))
return getSingletonTypes().anyType;
const TableTypeVar* mtt = getTableType(unwrapped);
if (!mtt)
{
errors.push_back(TypeError{location, GenericError{"Metatable was not a table."}});
return std::nullopt;
}
auto it = mtt->props.find(entry);
if (it != mtt->props.end())
return it->second.type;
else
return std::nullopt;
}
std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, const ScopePtr& globalScope, TypeId ty, Name name, Location location)
{
if (get<AnyTypeVar>(ty))
return ty;
if (const TableTypeVar* tableType = getTableType(ty))
{
const auto& it = tableType->props.find(name);
if (it != tableType->props.end())
return it->second.type;
}
std::optional<TypeId> mtIndex = findMetatableEntry(errors, globalScope, ty, "__index", location);
while (mtIndex)
{
TypeId index = follow(*mtIndex);
if (const auto& itt = getTableType(index))
{
const auto& fit = itt->props.find(name);
if (fit != itt->props.end())
return fit->second.type;
}
else if (const auto& itf = get<FunctionTypeVar>(index))
{
std::optional<TypeId> r = first(follow(itf->retType));
if (!r)
return getSingletonTypes().nilType;
else
return *r;
}
else if (get<AnyTypeVar>(index))
return getSingletonTypes().anyType;
else
errors.push_back(TypeError{location, GenericError{"__index should either be a function or table. Got " + toString(index)}});
mtIndex = findMetatableEntry(errors, globalScope, *mtIndex, "__index", location);
}
return std::nullopt;
}
} // namespace Luau