// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#include "Luau/TypeInfer.h"
#include "Luau/RecursionCounter.h"
#include "Fixture.h"
#include "doctest.h"
#include <algorithm>
using namespace Luau;
LUAU_FASTFLAG(DebugLuauDeferredConstraintResolution);
LUAU_FASTINT(LuauNormalizeCacheLimit);
LUAU_FASTINT(LuauTarjanChildLimit);
LUAU_FASTINT(LuauTypeInferIterationLimit);
LUAU_FASTINT(LuauTypeInferRecursionLimit);
LUAU_FASTINT(LuauTypeInferTypePackLoopLimit);
TEST_SUITE_BEGIN("ProvisionalTests");
// These tests check for behavior that differs from the final behavior we'd
// like to have. They serve to document the current state of the typechecker.
// When making future improvements, its very likely these tests will break and
// will need to be replaced.
/*
* This test falls into a sort of "do as I say" pit of consequences:
* Technically, the type of the type() function is <T>(T) -> string
*
* We thus infer that the argument to f is a free type.
* While we can still learn something about this argument, we can't seem to infer a union for it.
*
* Is this good? Maybe not, but I'm not sure what else we should do.
*/
TEST_CASE_FIXTURE(Fixture, "typeguard_inference_incomplete")
{
const std::string code = R"(
function f(a)
if type(a) == "boolean" then
local a1 = a
elseif a.fn() then
local a2 = a
end
end
)";
const std::string expected = R"(
function f(a:{fn:()->(a,b...)}): ()
if type(a) == 'boolean'then
local a1:boolean=a
elseif a.fn()then
local a2:{fn:()->(a,b...)}=a
end
end
)";
const std::string expectedWithNewSolver = R"(
function f(a:{fn:()->(unknown,...unknown)}): ()
if type(a) == 'boolean'then
local a1:{fn:()->(unknown,...unknown)}&boolean=a
elseif a.fn()then
local a2:{fn:()->(unknown,...unknown)}&(class|function|nil|number|string|thread|buffer|table)=a
end
end
)";
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK_EQ(expectedWithNewSolver, decorateWithTypes(code));
else
CHECK_EQ(expected, decorateWithTypes(code));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "luau-polyfill.Array.filter")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
// This test exercises the fact that we should reduce sealed/unsealed/free tables
// res is a unsealed table with type {((T & ~nil)?) & any}
// Because we do not reduce it fully, we cannot unify it with `Array<T> = { [number] : T}
// TLDR; reduction needs to reduce the indexer on res so it unifies with Array<T>
CheckResult result = check(R"(
--!strict
-- Implements Javascript's `Array.prototype.filter` as defined below
-- https://developer.cmozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
type Array<T> = { [number]: T }
type callbackFn<T> = (element: T, index: number, array: Array<T>) -> boolean
type callbackFnWithThisArg<T, U> = (thisArg: U, element: T, index: number, array: Array<T>) -> boolean
type Object = { [string]: any }
return function<T, U>(t: Array<T>, callback: callbackFn<T> | callbackFnWithThisArg<T, U>, thisArg: U?): Array<T>
local len = #t
local res = {}
if thisArg == nil then
for i = 1, len do
local kValue = t[i]
if kValue ~= nil then
if (callback :: callbackFn<T>)(kValue, i, t) then
res[i] = kValue
end
end
end
else
end
return res
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "xpcall_returns_what_f_returns")
{
const std::string code = R"(
local a, b, c = xpcall(function() return 1, "foo" end, function() return "foo", 1 end)
)";
const std::string expected = R"(
local a:boolean,b:number,c:string=xpcall(function(): (number,string)return 1,'foo'end,function(): (string,number)return'foo',1 end)
)";
CheckResult result = check(code);
CHECK("boolean" == toString(requireType("a")));
CHECK("number" == toString(requireType("b")));
CHECK("string" == toString(requireType("c")));
CHECK(expected == decorateWithTypes(code));
LUAU_REQUIRE_NO_ERRORS(result);
}
// We had a bug where if you have two type packs that looks like:
// { x, y }, ...
// { x }, ...
// It would infinitely grow the type pack because one WeirdIter is trying to catch up, but can't.
// However, the following snippet is supposed to generate an OccursCheckFailed, but it doesn't.
TEST_CASE_FIXTURE(Fixture, "weirditer_should_not_loop_forever")
{
// this flag is intentionally here doing nothing to demonstrate that we exit early via case detection
ScopedFastInt sfis{FInt::LuauTypeInferTypePackLoopLimit, 50};
CheckResult result = check(R"(
local function toVertexList(vertices, x, y, ...)
if not (x and y) then return vertices end -- no more arguments
vertices[#vertices + 1] = {x = x, y = y} -- set vertex
return toVertexList(vertices, ...) -- recurse
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
// This should also generate an OccursCheckFailed error too, like the above toVertexList snippet.
// at least up until we can get Luau to recognize this code as a valid function that iterates over a list of values in the pack.
TEST_CASE_FIXTURE(Fixture, "it_should_be_agnostic_of_actual_size")
{
CheckResult result = check(R"(
local function f(x, y, ...)
if not y then return x end
return f(x, ...)
end
f(3, 2, 1, 0)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
// Ideally setmetatable's second argument would be an optional free table.
// For now, infer it as just a free table.
TEST_CASE_FIXTURE(BuiltinsFixture, "setmetatable_constrains_free_type_into_free_table")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
CheckResult result = check(R"(
local a = {}
local b
setmetatable(a, b)
b = 1
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
TypeMismatch* tm = get<TypeMismatch>(result.errors[0]);
REQUIRE(tm);
CHECK_EQ("{- -}", toString(tm->wantedType));
CHECK_EQ("number", toString(tm->givenType));
}
// Luau currently doesn't yet know how to allow assignments when the binding was refined.
TEST_CASE_FIXTURE(Fixture, "while_body_are_also_refined")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
CheckResult result = check(R"(
type Node<T> = { value: T, child: Node<T>? }
local function visitor<T>(node: Node<T>, f: (T) -> ())
local current = node
while current do
f(current.value)
current = current.child -- TODO: Can't work just yet. It thinks 'current' can never be nil. :(
end
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ("Type 'Node<T>?' could not be converted into 'Node<T>'", toString(result.errors[0]));
}
// Originally from TypeInfer.test.cpp.
// I dont think type checking the metamethod at every site of == is the correct thing to do.
// We should be type checking the metamethod at the call site of setmetatable.
TEST_CASE_FIXTURE(BuiltinsFixture, "error_on_eq_metamethod_returning_a_type_other_than_boolean")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
CheckResult result = check(R"(
local tab = {a = 1}
setmetatable(tab, {__eq = function(a, b): number
return 1
end})
local tab2 = tab
local a = tab2 == tab
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
GenericError* ge = get<GenericError>(result.errors[0]);
REQUIRE(ge);
CHECK_EQ("Metamethod '__eq' must return type 'boolean'", ge->message);
}
// Belongs in TypeInfer.refinements.test.cpp.
// We need refine both operands as `never` in the `==` branch.
TEST_CASE_FIXTURE(Fixture, "lvalue_equals_another_lvalue_with_no_overlap")
{
CheckResult result = check(R"(
local function f(a: string, b: boolean?)
if a == b then
local foo, bar = a, b
else
local foo, bar = a, b
end
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "string"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "boolean?"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({5, 33})), "string"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({5, 36})), "boolean?"); // a ~= b
}
// Also belongs in TypeInfer.refinements.test.cpp.
// Just needs to fully support equality refinement. Which is annoying without type states.
TEST_CASE_FIXTURE(Fixture, "discriminate_from_x_not_equal_to_nil")
{
CheckResult result = check(R"(
type T = {x: string, y: number} | {x: nil, y: nil}
local function f(t: T)
if t.x ~= nil then
local foo = t
else
local bar = t
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("{ x: string, y: number }", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ("{ x: nil, y: nil }", toString(requireTypeAtPosition({7, 28})));
}
else
{
CHECK_EQ("{| x: string, y: number |}", toString(requireTypeAtPosition({5, 28})));
// Should be {| x: nil, y: nil |}
CHECK_EQ("{| x: nil, y: nil |} | {| x: string, y: number |}", toString(requireTypeAtPosition({7, 28})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "bail_early_if_unification_is_too_complicated" * doctest::timeout(0.5))
{
ScopedFastInt sffi{FInt::LuauTarjanChildLimit, 1};
ScopedFastInt sffi2{FInt::LuauTypeInferIterationLimit, 1};
CheckResult result = check(R"LUA(
local Result
Result = setmetatable({}, {})
Result.__index = Result
function Result.new(okValue)
local self = setmetatable({}, Result)
self:constructor(okValue)
return self
end
function Result:constructor(okValue)
self.okValue = okValue
end
function Result:ok(val) return Result.new(val) end
function Result:a(p0, p1, p2, p3, p4) return Result.new((self.okValue)) or p0 or p1 or p2 or p3 or p4 end
function Result:b(p0, p1, p2, p3, p4) return Result:ok((self.okValue)) or p0 or p1 or p2 or p3 or p4 end
function Result:c(p0, p1, p2, p3, p4) return Result:ok((self.okValue)) or p0 or p1 or p2 or p3 or p4 end
function Result:transpose(a)
return a and self.okValue:z(function(some)
return Result:ok(some)
end) or Result:ok(self.okValue)
end
)LUA");
auto it = std::find_if(
result.errors.begin(),
result.errors.end(),
[](TypeError& a)
{
return nullptr != get<UnificationTooComplex>(a);
}
);
if (it == result.errors.end())
{
dumpErrors(result);
FAIL("Expected a UnificationTooComplex error");
}
}
TEST_CASE_FIXTURE(Fixture, "do_not_ice_when_trying_to_pick_first_of_generic_type_pack")
{
// In-place quantification causes these types to have the wrong types but only because of nasty interaction with prototyping.
// The type of f is initially () -> free1...
// Then the prototype iterator advances, and checks the function expression assigned to g, which has the type () -> free2...
// In the body it calls f and returns what f() returns. This binds free2... with free1..., causing f and g to have same types.
// We then quantify g, leaving it with the final type <a...>() -> a...
// Because free1... and free2... were bound, in combination with in-place quantification, f's return type was also turned into a...
// Then the check iterator catches up, and checks the body of f, and attempts to quantify it too.
// Alas, one of the requirements for quantification is that a type must contain free types. () -> a... has no free types.
// Thus the quantification for f was no-op, which explains why f does not have any type parameters.
// Calling f() will attempt to instantiate the function type, which turns generics in type binders into to free types.
// However, instantiations only converts generics contained within the type binders of a function, so instantiation was also no-op.
// Which means that calling f() simply returned a... rather than an instantiation of it. And since the call site was not in tail position,
// picking first element in a... triggers an ICE because calls returning generic packs are unexpected.
CheckResult result = check(R"(
local function f() end
local g = function() return f() end
local x = (f()) -- should error: no return values to assign from the call to f
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK("() -> ()" == toString(requireType("f")));
CHECK("() -> ()" == toString(requireType("g")));
CHECK("nil" == toString(requireType("x")));
}
else
{
// f and g should have the type () -> ()
CHECK_EQ("() -> (a...)", toString(requireType("f")));
CHECK_EQ("<a...>() -> (a...)", toString(requireType("g")));
CHECK_EQ("any", toString(requireType("x"))); // any is returned instead of ICE for now
}
}
TEST_CASE_FIXTURE(Fixture, "specialization_binds_with_prototypes_too_early")
{
CheckResult result = check(R"(
local function id(x) return x end
local n2n: (number) -> number = id
local s2s: (string) -> string = id
)");
if (FFlag::DebugLuauDeferredConstraintResolution)
LUAU_REQUIRE_NO_ERRORS(result);
else
LUAU_REQUIRE_ERRORS(result); // Should not have any errors.
}
TEST_CASE_FIXTURE(Fixture, "weird_fail_to_unify_type_pack")
{
ScopedFastFlag sff[] = {
// I'm not sure why this is broken without DCR, but it seems to be fixed
// when DCR is enabled.
{FFlag::DebugLuauDeferredConstraintResolution, false},
};
CheckResult result = check(R"(
local function f() return end
local g = function() return f() end
)");
LUAU_REQUIRE_ERRORS(result); // Should not have any errors.
}
// Belongs in TypeInfer.builtins.test.cpp.
TEST_CASE_FIXTURE(BuiltinsFixture, "pcall_returns_at_least_two_value_but_function_returns_nothing")
{
CheckResult result = check(R"(
local function f(): () end
local ok, res = pcall(f)
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ("Function only returns 1 value, but 2 are required here", toString(result.errors[0]));
// LUAU_REQUIRE_NO_ERRORS(result);
// CHECK_EQ("boolean", toString(requireType("ok")));
// CHECK_EQ("any", toString(requireType("res")));
}
// Belongs in TypeInfer.builtins.test.cpp.
TEST_CASE_FIXTURE(BuiltinsFixture, "choose_the_right_overload_for_pcall")
{
CheckResult result = check(R"(
local function f(): number
if math.random() > 0.5 then
return 5
else
error("something")
end
end
local ok, res = pcall(f)
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("boolean", toString(requireType("ok")));
CHECK_EQ("number", toString(requireType("res")));
// CHECK_EQ("any", toString(requireType("res")));
}
// Belongs in TypeInfer.builtins.test.cpp.
TEST_CASE_FIXTURE(BuiltinsFixture, "function_returns_many_things_but_first_of_it_is_forgotten")
{
CheckResult result = check(R"(
local function f(): (number, string, boolean)
if math.random() > 0.5 then
return 5, "hello", true
else
error("something")
end
end
local ok, res, s, b = pcall(f)
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("boolean", toString(requireType("ok")));
CHECK_EQ("number", toString(requireType("res")));
// CHECK_EQ("any", toString(requireType("res")));
CHECK_EQ("string", toString(requireType("s")));
CHECK_EQ("boolean", toString(requireType("b")));
}
TEST_CASE_FIXTURE(Fixture, "free_is_not_bound_to_any")
{
CheckResult result = check(R"(
local function foo(f: (any) -> (), x)
f(x)
end
)");
CHECK_EQ("((any) -> (), any) -> ()", toString(requireType("foo")));
}
TEST_CASE_FIXTURE(Fixture, "dcr_can_partially_dispatch_a_constraint")
{
ScopedFastFlag sff[] = {
{FFlag::DebugLuauDeferredConstraintResolution, true},
};
CheckResult result = check(R"(
local function hasDivisors(value: number)
end
function prime_iter(state, index)
hasDivisors(index)
index += 1
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Solving this requires recognizing that we can't dispatch a constraint
// like this without doing further work:
//
// (*blocked*) -> () <: (number) -> (b...)
//
// We solve this by searching both types for BlockedTypes and block the
// constraint on any we find. It also gets the job done, but I'm worried
// about the efficiency of doing so many deep type traversals and it may
// make us more prone to getting stuck on constraint cycles.
//
// If this doesn't pan out, a possible solution is to go further down the
// path of supporting partial constraint dispatch. The way it would work is
// that we'd dispatch the above constraint by binding b... to (), but we
// would append a new constraint number <: *blocked* to the constraint set
// to be solved later. This should be faster and theoretically less prone
// to cyclic constraint dependencies.
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK("(unknown, number) -> ()" == toString(requireType("prime_iter")));
else
CHECK("<a>(a, number) -> ()" == toString(requireType("prime_iter")));
}
TEST_CASE_FIXTURE(Fixture, "free_options_cannot_be_unified_together")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
TypeArena arena;
TypeId nilType = builtinTypes->nilType;
std::unique_ptr scope = std::make_unique<Scope>(builtinTypes->anyTypePack);
TypeId free1 = arena.addType(FreeType{scope.get()});
TypeId option1 = arena.addType(UnionType{{nilType, free1}});
TypeId free2 = arena.addType(FreeType{scope.get()});
TypeId option2 = arena.addType(UnionType{{nilType, free2}});
InternalErrorReporter iceHandler;
UnifierSharedState sharedState{&iceHandler};
Normalizer normalizer{&arena, builtinTypes, NotNull{&sharedState}};
Unifier u{NotNull{&normalizer}, NotNull{scope.get()}, Location{}, Variance::Covariant};
if (FFlag::DebugLuauDeferredConstraintResolution)
u.enableNewSolver();
u.tryUnify(option1, option2);
CHECK(!u.failure);
u.log.commit();
ToStringOptions opts;
CHECK("a?" == toString(option1, opts));
// CHECK("a?" == toString(option2, opts)); // This should hold, but does not.
CHECK("b?" == toString(option2, opts)); // This should not hold.
}
TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop_with_zero_iterators")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
CheckResult result = check(R"(
function no_iter() end
for key in no_iter() do end -- This should not be ok
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
// Ideally, we would not try to export a function type with generic types from incorrect scope
TEST_CASE_FIXTURE(BuiltinsFixture, "generic_type_leak_to_module_interface")
{
fileResolver.source["game/A"] = R"(
local wrapStrictTable
local metatable = {
__index = function(self, key)
local value = self.__tbl[key]
if type(value) == "table" then
-- unification of the free 'wrapStrictTable' with this function type causes generics of this function to leak out of scope
return wrapStrictTable(value, self.__name .. "." .. key)
end
return value
end,
}
return wrapStrictTable
)";
frontend.check("game/A");
fileResolver.source["game/B"] = R"(
local wrapStrictTable = require(game.A)
local Constants = {}
return wrapStrictTable(Constants, "Constants")
)";
frontend.check("game/B");
ModulePtr m = frontend.moduleResolver.getModule("game/B");
REQUIRE(m);
std::optional<TypeId> result = first(m->returnType);
REQUIRE(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK_EQ("unknown", toString(*result));
else
CHECK_MESSAGE(get<AnyType>(*result), *result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "generic_type_leak_to_module_interface_variadic")
{
fileResolver.source["game/A"] = R"(
local wrapStrictTable
local metatable = {
__index = function<T>(self, key, ...: T)
local value = self.__tbl[key]
if type(value) == "table" then
-- unification of the free 'wrapStrictTable' with this function type causes generics of this function to leak out of scope
return wrapStrictTable(value, self.__name .. "." .. key)
end
return ...
end,
}
return wrapStrictTable
)";
frontend.check("game/A");
fileResolver.source["game/B"] = R"(
local wrapStrictTable = require(game.A)
local Constants = {}
return wrapStrictTable(Constants, "Constants")
)";
frontend.check("game/B");
ModulePtr m = frontend.moduleResolver.getModule("game/B");
REQUIRE(m);
std::optional<TypeId> result = first(m->returnType);
REQUIRE(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK("unknown" == toString(*result));
else
CHECK("any" == toString(*result));
}
namespace
{
struct IsSubtypeFixture : Fixture
{
bool isSubtype(TypeId a, TypeId b)
{
ModulePtr module = getMainModule();
REQUIRE(module);
if (!module->hasModuleScope())
FAIL("isSubtype: module scope data is not available");
return ::Luau::isSubtype(a, b, NotNull{module->getModuleScope().get()}, builtinTypes, ice);
}
};
} // namespace
TEST_CASE_FIXTURE(IsSubtypeFixture, "intersection_of_functions_of_different_arities")
{
check(R"(
type A = (any) -> ()
type B = (any, any) -> ()
type T = A & B
local a: A
local b: B
local t: T
)");
[[maybe_unused]] TypeId a = requireType("a");
[[maybe_unused]] TypeId b = requireType("b");
// CHECK(!isSubtype(a, b)); // !!
// CHECK(!isSubtype(b, a));
CHECK("((any) -> ()) & ((any, any) -> ())" == toString(requireType("t")));
}
TEST_CASE_FIXTURE(IsSubtypeFixture, "functions_with_mismatching_arity")
{
check(R"(
local a: (number) -> ()
local b: () -> ()
local c: () -> number
)");
TypeId a = requireType("a");
TypeId b = requireType("b");
TypeId c = requireType("c");
// CHECK(!isSubtype(b, a));
// CHECK(!isSubtype(c, a));
CHECK(!isSubtype(a, b));
// CHECK(!isSubtype(c, b));
CHECK(!isSubtype(a, c));
CHECK(!isSubtype(b, c));
}
TEST_CASE_FIXTURE(IsSubtypeFixture, "functions_with_mismatching_arity_but_optional_parameters")
{
/*
* (T0..TN) <: (T0..TN, A?)
* (T0..TN) <: (T0..TN, any)
* (T0..TN, A?) </: (T0..TN) We don't technically need to spell this out, but it's quite important.
* T <: T
* if A <: B and B <: C then A <: C
* T -> R <: U -> S if U <: T and R <: S
* A | B <: T if A <: T and B <: T
* T <: A | B if T <: A or T <: B
*/
check(R"(
local a: (number?) -> ()
local b: (number) -> ()
local c: (number, number?) -> ()
)");
TypeId a = requireType("a");
TypeId b = requireType("b");
TypeId c = requireType("c");
/*
* (number) -> () </: (number?) -> ()
* because number? </: number (because number <: number, but nil </: number)
*/
CHECK(!isSubtype(b, a));
/*
* (number, number?) </: (number?) -> ()
* because number? </: number (as above)
*/
CHECK(!isSubtype(c, a));
/*
* (number?) -> () <: (number) -> ()
* because number <: number? (because number <: number)
*/
CHECK(isSubtype(a, b));
/*
* (number, number?) -> () <: (number) -> (number)
* The packs have inequal lengths, but (number) <: (number, number?)
* and number <: number
*/
// CHECK(!isSubtype(c, b));
/*
* (number?) -> () </: (number, number?) -> ()
* because (number, number?) </: (number)
*/
// CHECK(!isSubtype(a, c));
/*
* (number) -> () </: (number, number?) -> ()
* because (number, number?) </: (number)
*/
// CHECK(!isSubtype(b, c));
}
TEST_CASE_FIXTURE(IsSubtypeFixture, "functions_with_mismatching_arity_but_any_is_an_optional_param")
{
check(R"(
local a: (number?) -> ()
local b: (number) -> ()
local c: (number, any) -> ()
)");
TypeId a = requireType("a");
TypeId b = requireType("b");
TypeId c = requireType("c");
/*
* (number) -> () </: (number?) -> ()
* because number? </: number (because number <: number, but nil </: number)
*/
CHECK(!isSubtype(b, a));
/*
* (number, any) </: (number?) -> ()
* because number? </: number (as above)
*/
CHECK(!isSubtype(c, a));
/*
* (number?) -> () <: (number) -> ()
* because number <: number? (because number <: number)
*/
CHECK(isSubtype(a, b));
/*
* (number, any) -> () </: (number) -> (number)
* The packs have inequal lengths
*/
// CHECK(!isSubtype(c, b));
/*
* (number?) -> () </: (number, any) -> ()
* The packs have inequal lengths
*/
// CHECK(!isSubtype(a, c));
/*
* (number) -> () </: (number, any) -> ()
* The packs have inequal lengths
*/
// CHECK(!isSubtype(b, c));
}
TEST_CASE_FIXTURE(Fixture, "assign_table_with_refined_property_with_a_similar_type_is_illegal")
{
CheckResult result = check(R"(
local t: {x: number?} = {x = nil}
if t.x then
local u: {x: number} = t
end
)");
if (FFlag::DebugLuauDeferredConstraintResolution)
LUAU_REQUIRE_NO_ERRORS(result); // This is wrong. We should be rejecting this assignment.
else
{
LUAU_REQUIRE_ERROR_COUNT(1, result);
const std::string expected = R"(Type
'{| x: number? |}'
could not be converted into
'{| x: number |}'
caused by:
Property 'x' is not compatible.
Type 'number?' could not be converted into 'number' in an invariant context)";
CHECK_EQ(expected, toString(result.errors[0]));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "table_insert_with_a_singleton_argument")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
CheckResult result = check(R"(
local function foo(t, x)
if x == "hi" or x == "bye" then
table.insert(t, x)
end
return t
end
local t = foo({}, "hi")
table.insert(t, "totally_unrelated_type" :: "totally_unrelated_type")
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK_EQ("{string}", toString(requireType("t")));
else
{
// We'd really like for this to be {string}
CHECK_EQ("{string | string}", toString(requireType("t")));
}
}
// We really should be warning on this. We have no guarantee that T has any properties.
TEST_CASE_FIXTURE(Fixture, "lookup_prop_of_intersection_containing_unions_of_tables_that_have_the_prop")
{
CheckResult result = check(R"(
local function mergeOptions<T>(options: T & ({variable: string} | {variable: number}))
return options.variable
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
// LUAU_REQUIRE_ERROR_COUNT(1, result);
// const UnknownProperty* unknownProp = get<UnknownProperty>(result.errors[0]);
// REQUIRE(unknownProp);
// CHECK("variable" == unknownProp->key);
}
TEST_CASE_FIXTURE(Fixture, "expected_type_should_be_a_helpful_deduction_guide_for_function_calls")
{
CheckResult result = check(R"(
type Ref<T> = { val: T }
local function useRef<T>(x: T): Ref<T?>
return { val = x }
end
local x: Ref<number?> = useRef(nil)
)");
if (FFlag::DebugLuauDeferredConstraintResolution)
{
// This bug is fixed in the new solver.
LUAU_REQUIRE_ERROR_COUNT(1, result);
}
else
{
// This is actually wrong! Sort of. It's doing the wrong thing, it's actually asking whether
// `{| val: number? |} <: {| val: nil |}`
// instead of the correct way, which is
// `{| val: nil |} <: {| val: number? |}`
LUAU_REQUIRE_NO_ERRORS(result);
}
}
TEST_CASE_FIXTURE(Fixture, "floating_generics_should_not_be_allowed")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
CheckResult result = check(R"(
local assign : <T, U, V, W>(target: T, source0: U?, source1: V?, source2: W?, ...any) -> T & U & V & W = (nil :: any)
-- We have a big problem here: The generics U, V, and W are not bound to anything!
-- Things get strange because of this.
local benchmark = assign({})
local options = benchmark.options
do
local resolve2: any = nil
options.fn({
resolve = function(...)
resolve2(...)
end,
})
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "free_options_can_be_unified_together")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
TypeArena arena;
TypeId nilType = builtinTypes->nilType;
std::unique_ptr scope = std::make_unique<Scope>(builtinTypes->anyTypePack);
TypeId free1 = arena.addType(FreeType{scope.get()});
TypeId option1 = arena.addType(UnionType{{nilType, free1}});
TypeId free2 = arena.addType(FreeType{scope.get()});
TypeId option2 = arena.addType(UnionType{{nilType, free2}});
InternalErrorReporter iceHandler;
UnifierSharedState sharedState{&iceHandler};
Normalizer normalizer{&arena, builtinTypes, NotNull{&sharedState}};
Unifier u{NotNull{&normalizer}, NotNull{scope.get()}, Location{}, Variance::Covariant};
if (FFlag::DebugLuauDeferredConstraintResolution)
u.enableNewSolver();
u.tryUnify(option1, option2);
CHECK(!u.failure);
u.log.commit();
ToStringOptions opts;
CHECK("a?" == toString(option1, opts));
CHECK("b?" == toString(option2, opts)); // should be `a?`.
}
TEST_CASE_FIXTURE(Fixture, "unify_more_complex_unions_that_include_nil")
{
CheckResult result = check(R"(
type Record = {prop: (string | boolean)?}
function concatPagination(prop: (string | boolean | nil)?): Record
return {prop = prop}
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "optional_class_instances_are_invariant_old_solver")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
createSomeClasses(&frontend);
CheckResult result = check(R"(
function foo(ref: {current: Parent?})
end
function bar(ref: {current: Child?})
foo(ref)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "optional_class_instances_are_invariant_new_solver")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, true};
createSomeClasses(&frontend);
CheckResult result = check(R"(
function foo(ref: {read current: Parent?})
end
function bar(ref: {read current: Child?})
foo(ref)
end
)");
LUAU_REQUIRE_ERROR_COUNT(0, result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "luau-polyfill.Map.entries")
{
fileResolver.source["Module/Map"] = R"(
--!strict
type Object = { [any]: any }
type Array<T> = { [number]: T }
type Table<T, V> = { [T]: V }
type Tuple<T, V> = Array<T | V>
local Map = {}
export type Map<K, V> = {
size: number,
-- method definitions
set: (self: Map<K, V>, K, V) -> Map<K, V>,
get: (self: Map<K, V>, K) -> V | nil,
clear: (self: Map<K, V>) -> (),
delete: (self: Map<K, V>, K) -> boolean,
has: (self: Map<K, V>, K) -> boolean,
keys: (self: Map<K, V>) -> Array<K>,
values: (self: Map<K, V>) -> Array<V>,
entries: (self: Map<K, V>) -> Array<Tuple<K, V>>,
ipairs: (self: Map<K, V>) -> any,
[K]: V,
_map: { [K]: V },
_array: { [number]: K },
}
function Map:entries()
return {}
end
local function coerceToTable(mapLike: Map<any, any> | Table<any, any>): Array<Tuple<any, any>>
local e = mapLike:entries();
return e
end
)";
CheckResult result = frontend.check("Module/Map");
LUAU_REQUIRE_NO_ERRORS(result);
}
// We would prefer this unification to be able to complete, but at least it should not crash
TEST_CASE_FIXTURE(BuiltinsFixture, "table_unification_infinite_recursion")
{
// The new solver doesn't recurse as heavily in this situation.
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, false};
#if defined(_NOOPT) || defined(_DEBUG)
ScopedFastInt LuauTypeInferRecursionLimit{FInt::LuauTypeInferRecursionLimit, 100};
#endif
fileResolver.source["game/A"] = R"(
local tbl = {}
function tbl:f1(state)
self.someNonExistentvalue2 = state
end
function tbl:f2()
self.someNonExistentvalue:Dc()
end
function tbl:f3()
self:f2()
self:f1(false)
end
return tbl
)";
fileResolver.source["game/B"] = R"(
local tbl = require(game.A)
tbl:f3()
)";
CheckResult result = frontend.check("game/B");
LUAU_REQUIRE_ERROR_COUNT(1, result);
}
// Ideally, unification with any will not cause a 2^n normalization of a function overload
TEST_CASE_FIXTURE(BuiltinsFixture, "normalization_limit_in_unify_with_any")
{
ScopedFastFlag sff[] = {
{FFlag::DebugLuauDeferredConstraintResolution, true},
};
// With default limit, this test will take 10 seconds in NoOpt
ScopedFastInt luauNormalizeCacheLimit{FInt::LuauNormalizeCacheLimit, 1000};
// Build a function type with a large overload set
const int parts = 100;
std::string source;
for (int i = 0; i < parts; i++)
formatAppend(source, "type T%d = { f%d: number }\n", i, i);
source += "type Instance = { new: (('s0', extra: Instance?) -> T0)";
for (int i = 1; i < parts; i++)
formatAppend(source, " & (('s%d', extra: Instance?) -> T%d)", i, i);
source += " }\n";
source += R"(
local Instance: Instance = {} :: any
local function foo(a: typeof(Instance.new)) return if a then 2 else 3 end
foo(1 :: any)
)";
CheckResult result = check(source);
LUAU_REQUIRE_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "luau_roact_useState_nilable_state_1")
{
ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, true};
CheckResult result = check(R"(
type Dispatch<A> = (A) -> ()
type BasicStateAction<S> = ((S) -> S) | S
type ScriptConnection = { Disconnect: (ScriptConnection) -> () }
local blah = nil :: any
local function useState<S>(
initialState: (() -> S) | S,
...
): (S, Dispatch<BasicStateAction<S>>)
return blah, blah
end
local a, b = useState(nil :: ScriptConnection?)
if a then
a:Disconnect()
b(nil :: ScriptConnection?)
end
)");
if (FFlag::DebugLuauDeferredConstraintResolution)
LUAU_REQUIRE_NO_ERRORS(result);
else
{
// This is a known bug in the old solver.
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK(Location{{19, 14}, {19, 41}} == result.errors[0].location);
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "luau_roact_useState_minimization")
{
// We don't expect this test to work on the old solver, but it also does not yet work on the new solver.
// So, we can't just put a scoped fast flag here, or it would block CI.
if (!FFlag::DebugLuauDeferredConstraintResolution)
return;
CheckResult result = check(R"(
type BasicStateAction<S> = ((S) -> S) | S
type Dispatch<A> = (A) -> ()
local function useState<S>(
initialState: (() -> S) | S
): (S, Dispatch<BasicStateAction<S>>)
-- fake impl that obeys types
local val = if type(initialState) == "function" then initialState() else initialState
return val, function(value)
return value
end
end
local test, setTest = useState(nil :: string?)
setTest(nil) -- this line causes the type to be narrowed in the old solver!!!
local function update(value: string)
print(test)
setTest(value)
end
update("hello")
)");
// We actually expect this code to be fine.
LUAU_REQUIRE_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "bin_prov")
{
CheckResult result = check(R"(
local Bin = {}
function Bin:add(item)
self.head = { item = item}
return item
end
function Bin:destroy()
while self.head do
local item = self.head.item
if type(item) == "function" then
item()
elseif item.Destroy ~= nil then
end
self.head = self.head.next
end
end
)");
}
TEST_CASE_FIXTURE(BuiltinsFixture, "update_phonemes_minimized")
{
CheckResult result = check(R"(
local video
function(response)
for index = 1, #response do
video = video
end
return video
end
)");
LUAU_REQUIRE_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "table_containing_non_final_type_is_erroneously_cached")
{
TypeArena arena;
Scope globalScope(builtinTypes->anyTypePack);
UnifierSharedState sharedState{&ice};
Normalizer normalizer{&arena, builtinTypes, NotNull{&sharedState}};
TypeId tableTy = arena.addType(TableType{});
TableType* table = getMutable<TableType>(tableTy);
REQUIRE(table);
TypeId freeTy = arena.freshType(&globalScope);
table->props["foo"] = Property::rw(freeTy);
std::shared_ptr<const NormalizedType> n1 = normalizer.normalize(tableTy);
std::shared_ptr<const NormalizedType> n2 = normalizer.normalize(tableTy);
// This should not hold
CHECK(n1 == n2);
}
// This is doable with the new solver, but there are some problems we have to work out first.
// CLI-111113
TEST_CASE_FIXTURE(Fixture, "we_cannot_infer_functions_that_return_inconsistently")
{
CheckResult result = check(R"(
function find_first<T>(tbl: {T}, el)
for i, e in tbl do
if e == el then
return i
end
end
return nil
end
)");
#if 0
// This #if block describes what should happen.
LUAU_CHECK_NO_ERRORS(result);
// The second argument has type unknown because the == operator does not
// constrain the type of el.
CHECK("<T>({T}, unknown) -> number?" == toString(requireType("find_first")));
#else
// This is what actually happens right now.
if (FFlag::DebugLuauDeferredConstraintResolution)
{
LUAU_CHECK_ERROR_COUNT(2, result);
// The second argument should be unknown. CLI-111111
CHECK("<T>({T}, 'b) -> number" == toString(requireType("find_first")));
}
else
{
LUAU_CHECK_ERROR_COUNT(1, result);
CHECK("<T, b>({T}, b) -> number" == toString(requireType("find_first")));
}
#endif
}
TEST_SUITE_END();