luau/tests/Unifier2.test.cpp

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// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#include "Luau/Scope.h"
#include "Luau/ToString.h"
#include "Luau/TypeArena.h"
#include "Luau/Unifier2.h"
#include "Luau/Error.h"
#include "ScopedFlags.h"
#include "doctest.h"
using namespace Luau;
struct Unifier2Fixture
{
TypeArena arena;
BuiltinTypes builtinTypes;
Scope scope{builtinTypes.anyTypePack};
InternalErrorReporter iceReporter;
Unifier2 u2{NotNull{&arena}, NotNull{&builtinTypes}, NotNull{&iceReporter}};
ToStringOptions opts;
ScopedFastFlag sff{"DebugLuauDeferredConstraintResolution", true};
std::pair<TypeId, FreeType*> freshType()
{
FreeType ft{&scope, builtinTypes.neverType, builtinTypes.unknownType};
TypeId ty = arena.addType(ft);
FreeType* ftv = getMutable<FreeType>(ty);
REQUIRE(ftv != nullptr);
return {ty, ftv};
}
std::string toString(TypeId ty)
{
return ::Luau::toString(ty, opts);
}
};
TEST_SUITE_BEGIN("Unifier2");
TEST_CASE_FIXTURE(Unifier2Fixture, "T <: number")
{
auto [left, freeLeft] = freshType();
CHECK(u2.unify(left, builtinTypes.numberType));
CHECK("never" == toString(freeLeft->lowerBound));
CHECK("number" == toString(freeLeft->upperBound));
}
TEST_CASE_FIXTURE(Unifier2Fixture, "number <: T")
{
auto [right, freeRight] = freshType();
CHECK(u2.unify(builtinTypes.numberType, right));
CHECK("number" == toString(freeRight->lowerBound));
CHECK("unknown" == toString(freeRight->upperBound));
}
TEST_CASE_FIXTURE(Unifier2Fixture, "T <: U")
{
auto [left, freeLeft] = freshType();
auto [right, freeRight] = freshType();
CHECK(u2.unify(left, right));
CHECK("t1 where t1 = ('a <: (t1 <: 'b))" == toString(left));
CHECK("t1 where t1 = (('a <: t1) <: 'b)" == toString(right));
CHECK("never" == toString(freeLeft->lowerBound));
CHECK("t1 where t1 = (('a <: t1) <: 'b)" == toString(freeLeft->upperBound));
CHECK("t1 where t1 = ('a <: (t1 <: 'b))" == toString(freeRight->lowerBound));
CHECK("unknown" == toString(freeRight->upperBound));
}
TEST_CASE_FIXTURE(Unifier2Fixture, "(string) -> () <: (X) -> Y...")
{
TypeId stringToUnit = arena.addType(FunctionType{arena.addTypePack({builtinTypes.stringType}), arena.addTypePack({})});
auto [x, xFree] = freshType();
TypePackId y = arena.freshTypePack(&scope);
TypeId xToY = arena.addType(FunctionType{arena.addTypePack({x}), y});
u2.unify(stringToUnit, xToY);
CHECK("string" == toString(xFree->upperBound));
const TypePack* yPack = get<TypePack>(follow(y));
REQUIRE(yPack != nullptr);
CHECK(0 == yPack->head.size());
CHECK(!yPack->tail);
}
TEST_CASE_FIXTURE(Unifier2Fixture, "generalize_a_type_that_is_bounded_by_another_generalizable_type")
{
auto [t1, ft1] = freshType();
auto [t2, ft2] = freshType();
// t2 <: t1 <: unknown
// unknown <: t2 <: t1
ft1->lowerBound = t2;
ft2->upperBound = t1;
ft2->lowerBound = builtinTypes.unknownType;
auto t2generalized = u2.generalize(NotNull{&scope}, t2);
REQUIRE(t2generalized);
CHECK(follow(t1) == follow(t2));
auto t1generalized = u2.generalize(NotNull{&scope}, t1);
REQUIRE(t1generalized);
CHECK(builtinTypes.unknownType == follow(t1));
CHECK(builtinTypes.unknownType == follow(t2));
}
// Same as generalize_a_type_that_is_bounded_by_another_generalizable_type
// except that we generalize the types in the opposite order
TEST_CASE_FIXTURE(Unifier2Fixture, "generalize_a_type_that_is_bounded_by_another_generalizable_type_in_reverse_order")
{
auto [t1, ft1] = freshType();
auto [t2, ft2] = freshType();
// t2 <: t1 <: unknown
// unknown <: t2 <: t1
ft1->lowerBound = t2;
ft2->upperBound = t1;
ft2->lowerBound = builtinTypes.unknownType;
auto t1generalized = u2.generalize(NotNull{&scope}, t1);
REQUIRE(t1generalized);
CHECK(follow(t1) == follow(t2));
auto t2generalized = u2.generalize(NotNull{&scope}, t2);
REQUIRE(t2generalized);
CHECK(builtinTypes.unknownType == follow(t1));
CHECK(builtinTypes.unknownType == follow(t2));
}
TEST_SUITE_END();