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luau/tests/TypeInfer.refinements.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/Normalize.h"
#include "Luau/Scope.h"
#include "Luau/TypeInfer.h"
#include "Fixture.h"
#include "doctest.h"
LUAU_FASTFLAG(DebugLuauDeferredConstraintResolution)
LUAU_FASTFLAG(LuauTypeMismatchInvarianceInError)
using namespace Luau;
namespace
{
std::optional<WithPredicate<TypePackId>> magicFunctionInstanceIsA(
TypeChecker& typeChecker, const ScopePtr& scope, const AstExprCall& expr, WithPredicate<TypePackId> withPredicate)
{
if (expr.args.size != 1)
return std::nullopt;
auto index = expr.func->as<Luau::AstExprIndexName>();
auto str = expr.args.data[0]->as<Luau::AstExprConstantString>();
if (!index || !str)
return std::nullopt;
std::optional<LValue> lvalue = tryGetLValue(*index->expr);
std::optional<TypeFun> tfun = scope->lookupType(std::string(str->value.data, str->value.size));
if (!lvalue || !tfun)
return std::nullopt;
unfreeze(typeChecker.globalTypes);
TypePackId booleanPack = typeChecker.globalTypes.addTypePack({typeChecker.booleanType});
freeze(typeChecker.globalTypes);
return WithPredicate<TypePackId>{booleanPack, {IsAPredicate{std::move(*lvalue), expr.location, tfun->type}}};
}
std::vector<ConnectiveId> dcrMagicRefinementInstanceIsA(MagicRefinementContext ctx)
{
if (ctx.callSite->args.size != 1)
return {};
auto index = ctx.callSite->func->as<Luau::AstExprIndexName>();
auto str = ctx.callSite->args.data[0]->as<Luau::AstExprConstantString>();
if (!index || !str)
return {};
std::optional<DefId> def = ctx.dfg->getDef(index->expr);
if (!def)
return {};
std::optional<TypeFun> tfun = ctx.scope->lookupType(std::string(str->value.data, str->value.size));
if (!tfun)
return {};
return {ctx.connectiveArena->proposition(*def, tfun->type)};
}
struct RefinementClassFixture : BuiltinsFixture
{
RefinementClassFixture()
{
TypeArena& arena = typeChecker.globalTypes;
NotNull<Scope> scope{typeChecker.globalScope.get()};
unfreeze(arena);
TypeId vec3 = arena.addType(ClassTypeVar{"Vector3", {}, std::nullopt, std::nullopt, {}, nullptr, "Test"});
getMutable<ClassTypeVar>(vec3)->props = {
{"X", Property{typeChecker.numberType}},
{"Y", Property{typeChecker.numberType}},
{"Z", Property{typeChecker.numberType}},
};
TypeId inst = arena.addType(ClassTypeVar{"Instance", {}, std::nullopt, std::nullopt, {}, nullptr, "Test"});
TypePackId isAParams = arena.addTypePack({inst, typeChecker.stringType});
TypePackId isARets = arena.addTypePack({typeChecker.booleanType});
TypeId isA = arena.addType(FunctionTypeVar{isAParams, isARets});
getMutable<FunctionTypeVar>(isA)->magicFunction = magicFunctionInstanceIsA;
getMutable<FunctionTypeVar>(isA)->dcrMagicRefinement = dcrMagicRefinementInstanceIsA;
getMutable<ClassTypeVar>(inst)->props = {
{"Name", Property{typeChecker.stringType}},
{"IsA", Property{isA}},
};
TypeId folder = typeChecker.globalTypes.addType(ClassTypeVar{"Folder", {}, inst, std::nullopt, {}, nullptr, "Test"});
TypeId part = typeChecker.globalTypes.addType(ClassTypeVar{"Part", {}, inst, std::nullopt, {}, nullptr, "Test"});
getMutable<ClassTypeVar>(part)->props = {
{"Position", Property{vec3}},
};
typeChecker.globalScope->exportedTypeBindings["Vector3"] = TypeFun{{}, vec3};
typeChecker.globalScope->exportedTypeBindings["Instance"] = TypeFun{{}, inst};
typeChecker.globalScope->exportedTypeBindings["Folder"] = TypeFun{{}, folder};
typeChecker.globalScope->exportedTypeBindings["Part"] = TypeFun{{}, part};
for (const auto& [name, ty] : typeChecker.globalScope->exportedTypeBindings)
persist(ty.type);
freeze(typeChecker.globalTypes);
}
};
} // namespace
TEST_SUITE_BEGIN("RefinementTest");
TEST_CASE_FIXTURE(Fixture, "is_truthy_constraint")
{
CheckResult result = check(R"(
function f(v: string?)
if v then
local s = v
else
local s = v
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & ~(false?)", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("(string?) & ~~(false?)", toString(requireTypeAtPosition({5, 26})));
}
else
{
CHECK_EQ("string", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("nil", toString(requireTypeAtPosition({5, 26})));
}
}
TEST_CASE_FIXTURE(Fixture, "invert_is_truthy_constraint")
{
CheckResult result = check(R"(
function f(v: string?)
if not v then
local s = v
else
local s = v
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & ~~(false?)", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("(string?) & ~(false?)", toString(requireTypeAtPosition({5, 26})));
}
else
{
CHECK_EQ("nil", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("string", toString(requireTypeAtPosition({5, 26})));
}
}
TEST_CASE_FIXTURE(Fixture, "parenthesized_expressions_are_followed_through")
{
CheckResult result = check(R"(
function f(v: string?)
if (not v) then
local s = v
else
local s = v
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & ~~(false?)", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("(string?) & ~(false?)", toString(requireTypeAtPosition({5, 26})));
}
else
{
CHECK_EQ("nil", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("string", toString(requireTypeAtPosition({5, 26})));
}
}
TEST_CASE_FIXTURE(Fixture, "and_constraint")
{
CheckResult result = check(R"(
function f(a: string?, b: number?)
if a and b then
local x = a
local y = b
else
local x = a
local y = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & ~(false?)", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("(number?) & ~(false?)", toString(requireTypeAtPosition({4, 26})));
}
else
{
CHECK_EQ("string", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("number", toString(requireTypeAtPosition({4, 26})));
}
CHECK_EQ("string?", toString(requireTypeAtPosition({6, 26})));
CHECK_EQ("number?", toString(requireTypeAtPosition({7, 26})));
}
TEST_CASE_FIXTURE(Fixture, "not_and_constraint")
{
CheckResult result = check(R"(
function f(a: string?, b: number?)
if not (a and b) then
local x = a
local y = b
else
local x = a
local y = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("string?", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("number?", toString(requireTypeAtPosition({4, 26})));
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & ~(false?)", toString(requireTypeAtPosition({6, 26})));
CHECK_EQ("(number?) & ~(false?)", toString(requireTypeAtPosition({7, 26})));
}
else
{
CHECK_EQ("string", toString(requireTypeAtPosition({6, 26})));
CHECK_EQ("number", toString(requireTypeAtPosition({7, 26})));
}
}
TEST_CASE_FIXTURE(Fixture, "or_predicate_with_truthy_predicates")
{
CheckResult result = check(R"(
function f(a: string?, b: number?)
if a or b then
local x = a
local y = b
else
local x = a
local y = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("string?", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("number?", toString(requireTypeAtPosition({4, 26})));
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & ~~(false?)", toString(requireTypeAtPosition({6, 26})));
CHECK_EQ("(number?) & ~~(false?)", toString(requireTypeAtPosition({7, 26})));
}
else
{
CHECK_EQ("nil", toString(requireTypeAtPosition({6, 26})));
CHECK_EQ("nil", toString(requireTypeAtPosition({7, 26})));
}
}
TEST_CASE_FIXTURE(Fixture, "a_and_b_or_a_and_c")
{
CheckResult result = check(R"(
function f(a: string?, b: number?, c: boolean)
if (a and b) or (a and c) then
local foo = a
local bar = b
local baz = c
else
local foo = a
local bar = b
local baz = c
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string?) & (~(false?) | ~(false?))", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("number?", toString(requireTypeAtPosition({4, 28})));
CHECK_EQ("boolean", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ("string?", toString(requireTypeAtPosition({7, 28})));
CHECK_EQ("number?", toString(requireTypeAtPosition({8, 28})));
CHECK_EQ("boolean", toString(requireTypeAtPosition({9, 28})));
}
else
{
CHECK_EQ("string", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("number?", toString(requireTypeAtPosition({4, 28})));
CHECK_EQ("true", toString(requireTypeAtPosition({5, 28}))); // oh no! :(
CHECK_EQ("string?", toString(requireTypeAtPosition({7, 28})));
CHECK_EQ("number?", toString(requireTypeAtPosition({8, 28})));
CHECK_EQ("boolean", toString(requireTypeAtPosition({9, 28})));
}
}
TEST_CASE_FIXTURE(Fixture, "type_assertion_expr_carry_its_constraints")
{
CheckResult result = check(R"(
function g(a: number?, b: string?)
if (a :: any) and (b :: any) then
local x = a
local y = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("number?", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("string?", toString(requireTypeAtPosition({4, 26})));
}
else
{
// We're going to drop support for type refinements through type assertions.
CHECK_EQ("number", toString(requireTypeAtPosition({3, 26})));
CHECK_EQ("string", toString(requireTypeAtPosition({4, 26})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "typeguard_in_if_condition_position")
{
CheckResult result = check(R"(
function f(s: any)
if type(s) == "number" then
local n = s
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("any & number", toString(requireTypeAtPosition({3, 26})));
}
else
{
CHECK_EQ("number", toString(requireTypeAtPosition({3, 26})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "typeguard_in_assert_position")
{
CheckResult result = check(R"(
local a
assert(type(a) == "number")
local b = a
)");
LUAU_REQUIRE_NO_ERRORS(result);
REQUIRE_EQ("number", toString(requireType("b")));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "call_an_incompatible_function_after_using_typeguard")
{
CheckResult result = check(R"(
local function f(x: number)
return x
end
local function g(x: any)
if type(x) == "string" then
f(x)
end
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ("Type 'string' could not be converted into 'number'", toString(result.errors[0]));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "impossible_type_narrow_is_not_an_error")
{
// This unit test serves as a reminder to not implement this warning until Luau is intelligent enough.
// For instance, getting a value out of the indexer and checking whether the value exists is not an error.
CheckResult result = check(R"(
local t: {string} = {"a", "b", "c"}
local v = t[4]
if not v then
t[4] = "d"
else
print(v)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "truthy_constraint_on_properties")
{
CheckResult result = check(R"(
local t: {x: number?} = {x = 1}
if t.x then
local t2 = t
local foo = t.x
end
local bar = t.x
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK("{| x: number? |} & {| x: ~(false?) |}" == toString(requireTypeAtPosition({4, 23})));
CHECK("(number?) & ~(false?)" == toString(requireTypeAtPosition({5, 26})));
}
CHECK_EQ("number?", toString(requireType("bar")));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "index_on_a_refined_property")
{
CheckResult result = check(R"(
local t: {x: {y: string}?} = {x = {y = "hello!"}}
if t.x then
print(t.x.y)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "assert_non_binary_expressions_actually_resolve_constraints")
{
CheckResult result = check(R"(
local foo: string? = "hello"
assert(foo)
local bar: string = foo
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
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
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
if (FFlag::LuauTypeMismatchInvarianceInError)
{
CHECK_EQ(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)",
toString(result.errors[0]));
}
else
{
CHECK_EQ(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')",
toString(result.errors[0]));
}
}
TEST_CASE_FIXTURE(Fixture, "lvalue_is_equal_to_another_lvalue")
{
CheckResult result = check(R"(
local function f(a: (string | number)?, b: boolean?)
if a == b then
local foo, bar = a, b
else
local foo, bar = a, b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "((number | string)?) & unknown"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "(boolean?) & unknown"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({5, 33})), "((number | string)?) & unknown"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({5, 36})), "(boolean?) & unknown"); // a ~= b
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "(number | string)?"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "boolean?"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({5, 33})), "(number | string)?"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({5, 36})), "boolean?"); // a ~= b
}
}
TEST_CASE_FIXTURE(Fixture, "lvalue_is_equal_to_a_term")
{
CheckResult result = check(R"(
local function f(a: (string | number)?)
if a == 1 then
local foo = a
else
local foo = a
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(toString(requireTypeAtPosition({3, 28})), "((number | string)?) & unknown"); // a == 1
CHECK_EQ(toString(requireTypeAtPosition({5, 28})), "((number | string)?) & unknown"); // a ~= 1
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({3, 28})), "(number | string)?"); // a == 1;
CHECK_EQ(toString(requireTypeAtPosition({5, 28})), "(number | string)?"); // a ~= 1
}
}
TEST_CASE_FIXTURE(Fixture, "term_is_equal_to_an_lvalue")
{
CheckResult result = check(R"(
local function f(a: (string | number)?)
if "hello" == a then
local foo = a
else
local foo = a
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(toString(requireTypeAtPosition({3, 28})), R"("hello" & ((number | string)?))"); // a == "hello"
CHECK_EQ(toString(requireTypeAtPosition({5, 28})), R"(((number | string)?) & ~"hello")"); // a ~= "hello"
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({3, 28})), R"("hello")"); // a == "hello"
CHECK_EQ(toString(requireTypeAtPosition({5, 28})), R"((number | string)?)"); // a ~= "hello"
}
}
TEST_CASE_FIXTURE(Fixture, "lvalue_is_not_nil")
{
CheckResult result = check(R"(
local function f(a: (string | number)?)
if a ~= nil then
local foo = a
else
local foo = a
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(toString(requireTypeAtPosition({3, 28})), "((number | string)?) & ~nil"); // a ~= nil
CHECK_EQ(toString(requireTypeAtPosition({5, 28})), "((number | string)?) & unknown"); // a == nil
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({3, 28})), "number | string"); // a ~= nil
CHECK_EQ(toString(requireTypeAtPosition({5, 28})), "(number | string)?"); // a == nil
}
}
TEST_CASE_FIXTURE(Fixture, "free_type_is_equal_to_an_lvalue")
{
CheckResult result = check(R"(
local function f(a, b: string?)
if a == b then
local foo, bar = a, b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
ToStringOptions opts;
CHECK_EQ(toString(requireTypeAtPosition({3, 33}), opts), "a & unknown"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({3, 36}), opts), "(string?) & unknown"); // a == b
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "a"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "string?"); // a == b
}
}
TEST_CASE_FIXTURE(Fixture, "unknown_lvalue_is_not_synonymous_with_other_on_not_equal")
{
CheckResult result = check(R"(
local function f(a: any, b: {x: number}?)
if a ~= b then
local foo, bar = a, b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "any & unknown"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "({| x: number |}?) & unknown"); // a ~= b
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "any"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "{| x: number |}?"); // a ~= b
}
}
TEST_CASE_FIXTURE(Fixture, "string_not_equal_to_string_or_nil")
{
CheckResult result = check(R"(
local t: {string} = {"hello"}
local a: string = t[1]
local b: string? = nil
if a ~= b then
local foo, bar = a, b
else
local foo, bar = a, b
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(toString(requireTypeAtPosition({6, 29})), "string & unknown"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({6, 32})), "(string?) & unknown"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({8, 29})), "string & unknown"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({8, 32})), "(string?) & unknown"); // a == b
}
else
{
CHECK_EQ(toString(requireTypeAtPosition({6, 29})), "string"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({6, 32})), "string?"); // a ~= b
CHECK_EQ(toString(requireTypeAtPosition({8, 29})), "string"); // a == b
CHECK_EQ(toString(requireTypeAtPosition({8, 32})), "string?"); // a == b
}
}
TEST_CASE_FIXTURE(Fixture, "narrow_property_of_a_bounded_variable")
{
CheckResult result = check(R"(
local t
local u: {x: number?} = {x = nil}
t = u
if t.x then
local foo: number = t.x
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "type_narrow_to_vector")
{
CheckResult result = check(R"(
local function f(x)
if type(x) == "vector" then
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("*error-type*", toString(requireTypeAtPosition({3, 28})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "nonoptional_type_can_narrow_to_nil_if_sense_is_true")
{
CheckResult result = check(R"(
local t = {"hello"}
local v = t[2]
if type(v) == "nil" then
local foo = v
else
local foo = v
end
if not (type(v) ~= "nil") then
local foo = v
else
local foo = v
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("nil", toString(requireTypeAtPosition({4, 24}))); // type(v) == "nil"
CHECK_EQ("string", toString(requireTypeAtPosition({6, 24}))); // type(v) ~= "nil"
CHECK_EQ("nil", toString(requireTypeAtPosition({10, 24}))); // equivalent to type(v) == "nil"
CHECK_EQ("string", toString(requireTypeAtPosition({12, 24}))); // equivalent to type(v) ~= "nil"
}
TEST_CASE_FIXTURE(BuiltinsFixture, "typeguard_not_to_be_string")
{
CheckResult result = check(R"(
local function f(x: string | number | boolean)
if type(x) ~= "string" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(boolean | number | string) & ~string", toString(requireTypeAtPosition({3, 28}))); // type(x) ~= "string"
CHECK_EQ("(boolean | number | string) & string", toString(requireTypeAtPosition({5, 28}))); // type(x) == "string"
}
else
{
CHECK_EQ("boolean | number", toString(requireTypeAtPosition({3, 28}))); // type(x) ~= "string"
CHECK_EQ("string", toString(requireTypeAtPosition({5, 28}))); // type(x) == "string"
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "typeguard_narrows_for_table")
{
CheckResult result = check(R"(
local function f(x: string | {x: number} | {y: boolean})
if type(x) == "table" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("{| x: number |} | {| y: boolean |}", toString(requireTypeAtPosition({3, 28}))); // type(x) == "table"
CHECK_EQ("string", toString(requireTypeAtPosition({5, 28}))); // type(x) ~= "table"
}
TEST_CASE_FIXTURE(BuiltinsFixture, "typeguard_narrows_for_functions")
{
CheckResult result = check(R"(
local function weird(x: string | ((number) -> string))
if type(x) == "function" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(((number) -> string) | string) & function", toString(requireTypeAtPosition({3, 28}))); // type(x) == "function"
CHECK_EQ("(((number) -> string) | string) & ~function", toString(requireTypeAtPosition({5, 28}))); // type(x) ~= "function"
}
else
{
CHECK_EQ("(number) -> string", toString(requireTypeAtPosition({3, 28}))); // type(x) == "function"
CHECK_EQ("string", toString(requireTypeAtPosition({5, 28}))); // type(x) ~= "function"
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "type_guard_can_filter_for_intersection_of_tables")
{
CheckResult result = check(R"(
type XYCoord = {x: number} & {y: number}
local function f(t: XYCoord?)
if type(t) == "table" then
local foo = t
else
local foo = t
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("{| x: number |} & {| y: number |}", toString(requireTypeAtPosition({4, 28})));
CHECK_EQ("nil", toString(requireTypeAtPosition({6, 28})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "type_guard_can_filter_for_overloaded_function")
{
CheckResult result = check(R"(
type SomeOverloadedFunction = ((number) -> string) & ((string) -> number)
local function f(g: SomeOverloadedFunction?)
if type(g) == "function" then
local foo = g
else
local foo = g
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("((((number) -> string) & ((string) -> number))?) & function", toString(requireTypeAtPosition({4, 28})));
CHECK_EQ("((((number) -> string) & ((string) -> number))?) & ~function", toString(requireTypeAtPosition({6, 28})));
}
else
{
CHECK_EQ("((number) -> string) & ((string) -> number)", toString(requireTypeAtPosition({4, 28})));
CHECK_EQ("nil", toString(requireTypeAtPosition({6, 28})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "type_guard_narrowed_into_nothingness")
{
CheckResult result = check(R"(
local function f(t: {x: number})
if type(t) ~= "table" then
local foo = t
error(("Expected a table, got %s"):format(type(t)))
end
return t.x + 1
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("never", toString(requireTypeAtPosition({3, 28})));
}
TEST_CASE_FIXTURE(Fixture, "not_a_or_not_b")
{
CheckResult result = check(R"(
local function f(a: number?, b: number?)
if (not a) or (not b) then
local foo = a
local bar = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("number?", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("number?", toString(requireTypeAtPosition({4, 28})));
}
TEST_CASE_FIXTURE(Fixture, "not_a_or_not_b2")
{
CheckResult result = check(R"(
local function f(a: number?, b: number?)
if not (a and b) then
local foo = a
local bar = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("number?", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("number?", toString(requireTypeAtPosition({4, 28})));
}
TEST_CASE_FIXTURE(Fixture, "not_a_and_not_b")
{
CheckResult result = check(R"(
local function f(a: number?, b: number?)
if (not a) and (not b) then
local foo = a
local bar = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(number?) & ~~(false?)", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(number?) & ~~(false?)", toString(requireTypeAtPosition({4, 28})));
}
else
{
CHECK_EQ("nil", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("nil", toString(requireTypeAtPosition({4, 28})));
}
}
TEST_CASE_FIXTURE(Fixture, "not_a_and_not_b2")
{
CheckResult result = check(R"(
local function f(a: number?, b: number?)
if not (a or b) then
local foo = a
local bar = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(number?) & ~~(false?)", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(number?) & ~~(false?)", toString(requireTypeAtPosition({4, 28})));
}
else
{
CHECK_EQ("nil", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("nil", toString(requireTypeAtPosition({4, 28})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "either_number_or_string")
{
CheckResult result = check(R"(
local function f(x: any)
if type(x) == "number" or type(x) == "string" then
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(number | string) & any", toString(requireTypeAtPosition({3, 28})));
}
else
{
CHECK_EQ("number | string", toString(requireTypeAtPosition({3, 28})));
}
}
TEST_CASE_FIXTURE(Fixture, "not_t_or_some_prop_of_t")
{
CheckResult result = check(R"(
local function f(t: {x: boolean}?)
if not t or t.x then
local foo = t
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("{| x: boolean |}?", toString(requireTypeAtPosition({3, 28})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "assert_a_to_be_truthy_then_assert_a_to_be_number")
{
CheckResult result = check(R"(
local a: (number | string)?
assert(a)
local b = a
assert(type(a) == "number")
local c = a
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("number | string", toString(requireTypeAtPosition({3, 18})));
CHECK_EQ("number", toString(requireTypeAtPosition({5, 18})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "merge_should_be_fully_agnostic_of_hashmap_ordering")
{
// This bug came up because there was a mistake in Luau::merge where zipping on two maps would produce the wrong merged result.
CheckResult result = check(R"(
local function f(b: string | { x: string }, a)
assert(type(a) == "string")
assert(type(b) == "string" or type(b) == "table")
if type(b) == "string" then
local foo = b
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(string | {| x: string |}) & string", toString(requireTypeAtPosition({6, 28})));
}
else
{
CHECK_EQ("string", toString(requireTypeAtPosition({6, 28})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "refine_the_correct_types_opposite_of_when_a_is_not_number_or_string")
{
CheckResult result = check(R"(
local function f(a: string | number | boolean)
if type(a) ~= "number" and type(a) ~= "string" then
local foo = a
else
local foo = a
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(boolean | number | string) & ~number & ~string", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(boolean | number | string) & (number | string)", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("boolean", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("number | string", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "is_truthy_constraint_ifelse_expression")
{
CheckResult result = check(R"(
function f(v:string?)
return if v then v else tostring(v)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("string", toString(requireTypeAtPosition({2, 29})));
CHECK_EQ("nil", toString(requireTypeAtPosition({2, 45})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "invert_is_truthy_constraint_ifelse_expression")
{
CheckResult result = check(R"(
function f(v:string?)
return if not v then tostring(v) else v
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("nil", toString(requireTypeAtPosition({2, 42})));
CHECK_EQ("string", toString(requireTypeAtPosition({2, 50})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "type_comparison_ifelse_expression")
{
CheckResult result = check(R"(
function returnOne(x)
return 1
end
function f(v:any)
return if typeof(v) == "number" then v else returnOne(v)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("number", toString(requireTypeAtPosition({6, 49})));
CHECK_EQ("any", toString(requireTypeAtPosition({6, 66})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "correctly_lookup_a_shadowed_local_that_which_was_previously_refined")
{
CheckResult result = check(R"(
local foo: string? = "hi"
assert(foo)
local foo: number = 5
print(foo:sub(1, 1))
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ("Type 'number' does not have key 'sub'", toString(result.errors[0]));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "correctly_lookup_property_whose_base_was_previously_refined")
{
CheckResult result = check(R"(
type T = {x: string | number}
local t: T? = {x = "hi"}
if t then
if type(t.x) == "string" then
local foo = t.x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("string", toString(requireTypeAtPosition({5, 30})));
}
TEST_CASE_FIXTURE(Fixture, "correctly_lookup_property_whose_base_was_previously_refined2")
{
CheckResult result = check(R"(
type T = { x: { y: number }? }
local function f(t: T?)
if t and t.x then
local foo = t.x.y
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("number", toString(requireTypeAtPosition({5, 32})));
}
TEST_CASE_FIXTURE(Fixture, "apply_refinements_on_astexprindexexpr_whose_subscript_expr_is_constant_string")
{
CheckResult result = check(R"(
type T = { [string]: { prop: number }? }
local t: T = {}
if t["hello"] then
local foo = t["hello"].prop
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "discriminate_from_truthiness_of_x")
{
CheckResult result = check(R"(
type T = {tag: "missing", x: nil} | {tag: "exists", x: string}
local function f(t: T)
if t.x then
local foo = t
else
local bar = t
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(R"(({| tag: "exists", x: string |} | {| tag: "missing", x: nil |}) & {| x: ~(false?) |})", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ(
R"(({| tag: "exists", x: string |} | {| tag: "missing", x: nil |}) & {| x: ~~(false?) |})", toString(requireTypeAtPosition({7, 28})));
}
else
{
CHECK_EQ(R"({| tag: "exists", x: string |})", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ(R"({| tag: "exists", x: string |} | {| tag: "missing", x: nil |})", toString(requireTypeAtPosition({7, 28})));
}
}
TEST_CASE_FIXTURE(Fixture, "discriminate_tag")
{
CheckResult result = check(R"(
type Cat = {tag: "Cat", name: string, catfood: string}
type Dog = {tag: "Dog", name: string, dogfood: string}
type Animal = Cat | Dog
local function f(animal: Animal)
if animal.tag == "Cat" then
local cat = animal
elseif animal.tag == "Dog" then
local dog = animal
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(R"((Cat | Dog) & {| tag: "Cat" |})", toString(requireTypeAtPosition({7, 33})));
CHECK_EQ(R"((Cat | Dog) & {| tag: ~"Cat" |} & {| tag: "Dog" |})", toString(requireTypeAtPosition({9, 33})));
}
else
{
CHECK_EQ("Cat", toString(requireTypeAtPosition({7, 33})));
CHECK_EQ("Dog", toString(requireTypeAtPosition({9, 33})));
}
}
TEST_CASE_FIXTURE(Fixture, "discriminate_tag_with_implicit_else")
{
ScopedFastFlag sff{"LuauImplicitElseRefinement", true};
CheckResult result = check(R"(
type Cat = {tag: "Cat", name: string, catfood: string}
type Dog = {tag: "Dog", name: string, dogfood: string}
type Animal = Cat | Dog
local function f(animal: Animal)
if animal.tag == "Cat" then
local cat = animal
else
local dog = animal
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(R"((Cat | Dog) & {| tag: "Cat" |})", toString(requireTypeAtPosition({7, 33})));
CHECK_EQ(R"((Cat | Dog) & {| tag: ~"Cat" |})", toString(requireTypeAtPosition({9, 33})));
}
else
{
CHECK_EQ("Cat", toString(requireTypeAtPosition({7, 33})));
CHECK_EQ("Dog", toString(requireTypeAtPosition({9, 33})));
}
}
TEST_CASE_FIXTURE(Fixture, "and_or_peephole_refinement")
{
CheckResult result = check(R"(
local function len(a: {any})
return a and #a or nil
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "narrow_boolean_to_true_or_false")
{
CheckResult result = check(R"(
local function f(x: boolean)
if x then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("boolean & ~(false?)", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("boolean & ~~(false?)", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("true", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("false", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(Fixture, "discriminate_on_properties_of_disjoint_tables_where_that_property_is_true_or_false")
{
CheckResult result = check(R"(
type Ok<T> = { ok: true, value: T }
type Err<E> = { ok: false, error: E }
type Result<T, E> = Ok<T> | Err<E>
local function apply<T, E>(t: Result<T, E>, f: (T) -> (), g: (E) -> ())
if t.ok then
f(t.value)
else
g(t.error)
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "refine_a_property_not_to_be_nil_through_an_intersection_table")
{
CheckResult result = check(R"(
type T = {} & {f: ((string) -> string)?}
local function f(t: T, x)
if t.f then
t.f(x)
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(RefinementClassFixture, "discriminate_from_isa_of_x")
{
CheckResult result = check(R"(
type T = {tag: "Part", x: Part} | {tag: "Folder", x: Folder}
local function f(t: T)
if t.x:IsA("Part") then
local foo = t
else
local bar = t
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ(R"(({| tag: "Folder", x: Folder |} | {| tag: "Part", x: Part |}) & {| x: Part |})", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ(R"(({| tag: "Folder", x: Folder |} | {| tag: "Part", x: Part |}) & {| x: ~Part |})", toString(requireTypeAtPosition({7, 28})));
}
else
{
CHECK_EQ(R"({| tag: "Part", x: Part |})", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ(R"({| tag: "Folder", x: Folder |})", toString(requireTypeAtPosition({7, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "typeguard_cast_free_table_to_vector")
{
CheckResult result = check(R"(
local function f(vec)
local X, Y, Z = vec.X, vec.Y, vec.Z
if type(vec) == "vector" then
local foo = vec
elseif typeof(vec) == "Instance" then
local foo = vec
else
local foo = vec
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("Vector3", toString(requireTypeAtPosition({5, 28}))); // type(vec) == "vector"
CHECK_EQ("never", toString(requireTypeAtPosition({7, 28}))); // typeof(vec) == "Instance"
CHECK_EQ("{+ X: a, Y: b, Z: c +}", toString(requireTypeAtPosition({9, 28}))); // type(vec) ~= "vector" and typeof(vec) ~= "Instance"
}
TEST_CASE_FIXTURE(RefinementClassFixture, "typeguard_cast_instance_or_vector3_to_vector")
{
CheckResult result = check(R"(
local function f(x: Instance | Vector3)
if typeof(x) == "Vector3" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(Instance | Vector3) & Vector3", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(Instance | Vector3) & ~Vector3", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("Vector3", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Instance", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "type_narrow_for_all_the_userdata")
{
CheckResult result = check(R"(
local function f(x: string | number | Instance | Vector3)
if type(x) == "userdata" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("Instance | Vector3", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("number | string", toString(requireTypeAtPosition({5, 28})));
}
TEST_CASE_FIXTURE(RefinementClassFixture, "eliminate_subclasses_of_instance")
{
CheckResult result = check(R"(
local function f(x: Part | Folder | string)
if typeof(x) == "Instance" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(Folder | Part | string) & Instance", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(Folder | Part | string) & ~Instance", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("Folder | Part", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("string", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "narrow_from_subclasses_of_instance_or_string_or_vector3")
{
CheckResult result = check(R"(
local function f(x: Part | Folder | string | Vector3)
if typeof(x) == "Instance" then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(Folder | Part | Vector3 | string) & Instance", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(Folder | Part | Vector3 | string) & ~Instance", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("Folder | Part", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Vector3 | string", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "x_as_any_if_x_is_instance_elseif_x_is_table")
{
CheckResult result = check(R"(
--!nonstrict
local function f(x)
if typeof(x) == "Instance" and x:IsA("Folder") then
local foo = x
elseif typeof(x) == "table" then
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("Folder & Instance & {- -}", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ("(~Folder | ~Instance) & {- -} & never", toString(requireTypeAtPosition({7, 28})));
}
else
{
CHECK_EQ("Folder", toString(requireTypeAtPosition({5, 28})));
CHECK_EQ("any", toString(requireTypeAtPosition({7, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "refine_param_of_type_instance_without_using_typeof")
{
CheckResult result = check(R"(
local function f(x: Instance)
if x:IsA("Folder") then
local foo = x
elseif typeof(x) == "table" then
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("Folder & Instance", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Instance & ~Folder & never", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("Folder", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("never", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "refine_param_of_type_folder_or_part_without_using_typeof")
{
CheckResult result = check(R"(
local function f(x: Part | Folder)
if x:IsA("Folder") then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("(Folder | Part) & Folder", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("(Folder | Part) & ~Folder", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("Folder", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Part", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "isa_type_refinement_must_be_known_ahead_of_time")
{
CheckResult result = check(R"(
local function f(x): Instance
if x:IsA("Folder") then
local foo = x
else
local foo = x
end
return x
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("Instance", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Instance", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("Instance", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Instance", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(RefinementClassFixture, "x_is_not_instance_or_else_not_part")
{
CheckResult result = check(R"(
local function f(x: Part | Folder | string)
if typeof(x) ~= "Instance" or not x:IsA("Part") then
local foo = x
else
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("Folder | string", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("Part", toString(requireTypeAtPosition({5, 28})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "typeguard_doesnt_leak_to_elseif")
{
CheckResult result = check(R"(
function f(a)
if type(a) == "boolean" then
local a1 = a
elseif a.fn() then
local a2 = a
else
local a3 = a
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "refine_unknowns")
{
CheckResult result = check(R"(
local function f(x: unknown)
if type(x) == "string" then
local foo = x
else
local bar = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("unknown & string", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("unknown & ~string", toString(requireTypeAtPosition({5, 28})));
}
else
{
CHECK_EQ("string", toString(requireTypeAtPosition({3, 28})));
CHECK_EQ("unknown", toString(requireTypeAtPosition({5, 28})));
}
}
TEST_CASE_FIXTURE(BuiltinsFixture, "falsiness_of_TruthyPredicate_narrows_into_nil")
{
CheckResult result = check(R"(
local function f(t: {number})
local x = t[1]
if not x then
local foo = x
else
local bar = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("nil", toString(requireTypeAtPosition({4, 28})));
CHECK_EQ("number", toString(requireTypeAtPosition({6, 28})));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "what_nonsensical_condition")
{
CheckResult result = check(R"(
local function f(x)
if type(x) == "string" and type(x) == "number" then
local foo = x
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
CHECK_EQ("a & number & string", toString(requireTypeAtPosition({3, 28})));
}
else
{
CHECK_EQ("never", toString(requireTypeAtPosition({3, 28})));
}
}
TEST_CASE_FIXTURE(Fixture, "else_with_no_explicit_expression_should_also_refine_the_tagged_union")
{
ScopedFastFlag sff{"LuauImplicitElseRefinement", true};
CheckResult result = check(R"(
type Ok<T> = { tag: "ok", value: T }
type Err<E> = { tag: "err", err: E }
type Result<T, E> = Ok<T> | Err<E>
function and_then<T, U, E>(r: Result<T, E>, f: (T) -> U): Result<U, E>
if r.tag == "ok" then
return { tag = "ok", value = f(r.value) }
else
return r
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "fuzz_filtered_refined_types_are_followed")
{
ScopedFastFlag luauTypeInferMissingFollows{"LuauTypeInferMissingFollows", true};
CheckResult result = check(R"(
local _
do
local _ = _ ~= _ or _ or _
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_SUITE_END();
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