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luau/tests/TypeInfer.functions.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/AstQuery.h"
#include "Luau/BuiltinDefinitions.h"
#include "Luau/Error.h"
#include "Luau/Scope.h"
#include "Luau/TypeInfer.h"
#include "Luau/Type.h"
#include "Luau/VisitType.h"
#include "Fixture.h"
#include "doctest.h"
using namespace Luau;
LUAU_FASTFLAG(LuauInstantiateInSubtyping)
TEST_SUITE_BEGIN("TypeInferFunctions");
TEST_CASE_FIXTURE(Fixture, "tc_function")
{
CheckResult result = check("function five() return 5 end");
LUAU_REQUIRE_NO_ERRORS(result);
const FunctionType* fiveType = get<FunctionType>(requireType("five"));
REQUIRE(fiveType != nullptr);
}
TEST_CASE_FIXTURE(Fixture, "check_function_bodies")
{
CheckResult result = check("function myFunction() local a = 0 a = true end");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(result.errors[0], (TypeError{Location{Position{0, 44}, Position{0, 48}}, TypeMismatch{
builtinTypes->numberType,
builtinTypes->booleanType,
}}));
}
TEST_CASE_FIXTURE(Fixture, "cannot_hoist_interior_defns_into_signature")
{
// This test verifies that the signature does not have access to types
// declared within the body. Under DCR, if the function's inner scope
// encompasses the entire function expression, it would be possible for this
// to type check (but the solver output is somewhat undefined). This test
// ensures that this isn't the case.
CheckResult result = check(R"(
local function f(x: T)
type T = number
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK(result.errors[0] == TypeError{Location{{1, 28}, {1, 29}}, getMainSourceModule()->name,
UnknownSymbol{
"T",
UnknownSymbol::Context::Type,
}});
}
TEST_CASE_FIXTURE(Fixture, "infer_return_type")
{
CheckResult result = check("function take_five() return 5 end");
LUAU_REQUIRE_NO_ERRORS(result);
const FunctionType* takeFiveType = get<FunctionType>(requireType("take_five"));
REQUIRE(takeFiveType != nullptr);
std::vector<TypeId> retVec = flatten(takeFiveType->retTypes).first;
REQUIRE(!retVec.empty());
REQUIRE_EQ(*follow(retVec[0]), *builtinTypes->numberType);
}
TEST_CASE_FIXTURE(Fixture, "infer_from_function_return_type")
{
CheckResult result = check("function take_five() return 5 end local five = take_five()");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ(*builtinTypes->numberType, *follow(requireType("five")));
}
TEST_CASE_FIXTURE(Fixture, "infer_that_function_does_not_return_a_table")
{
CheckResult result = check(R"(
function take_five()
return 5
end
take_five().prop = 888
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(result.errors[0], (TypeError{Location{Position{5, 8}, Position{5, 24}}, NotATable{builtinTypes->numberType}}));
}
TEST_CASE_FIXTURE(Fixture, "generalize_table_property")
{
CheckResult result = check(R"(
local T = {}
T.foo = function(x)
return x
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
TypeId t = requireType("T");
const TableType* tt = get<TableType>(follow(t));
REQUIRE(tt);
TypeId fooTy = tt->props.at("foo").type();
CHECK("<a>(a) -> a" == toString(fooTy));
}
TEST_CASE_FIXTURE(Fixture, "vararg_functions_should_allow_calls_of_any_types_and_size")
{
CheckResult result = check(R"(
function f(...) end
f(1)
f("foo", 2)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "vararg_function_is_quantified")
{
CheckResult result = check(R"(
local T = {}
function T.f(...)
local result = {}
for i = 1, select("#", ...) do
local dictionary = select(i, ...)
for key, value in pairs(dictionary) do
result[key] = value
end
end
return result
end
return T
)");
LUAU_REQUIRE_NO_ERRORS(result);
auto r = first(getMainModule()->returnType);
REQUIRE(r);
TableType* ttv = getMutable<TableType>(*r);
REQUIRE(ttv);
REQUIRE(ttv->props.count("f"));
TypeId k = ttv->props["f"].type();
REQUIRE(k);
}
TEST_CASE_FIXTURE(Fixture, "list_only_alternative_overloads_that_match_argument_count")
{
CheckResult result = check(R"(
local multiply: ((number)->number) & ((number)->string) & ((number, number)->number)
multiply("")
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
if (FFlag::DebugLuauDeferredConstraintResolution)
{
GenericError* g = get<GenericError>(result.errors[0]);
REQUIRE(g);
CHECK(g->message == "None of the overloads for function that accept 1 arguments are compatible.");
}
else
{
TypeMismatch* tm = get<TypeMismatch>(result.errors[0]);
REQUIRE(tm);
CHECK_EQ(builtinTypes->numberType, tm->wantedType);
CHECK_EQ(builtinTypes->stringType, tm->givenType);
}
ExtraInformation* ei = get<ExtraInformation>(result.errors[1]);
REQUIRE(ei);
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK("Available overloads: (number) -> number; and (number) -> string" == ei->message);
else
CHECK_EQ("Other overloads are also not viable: (number) -> string", ei->message);
}
TEST_CASE_FIXTURE(Fixture, "list_all_overloads_if_no_overload_takes_given_argument_count")
{
CheckResult result = check(R"(
local multiply: ((number)->number) & ((number)->string) & ((number, number)->number)
multiply()
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
GenericError* ge = get<GenericError>(result.errors[0]);
REQUIRE(ge);
CHECK_EQ("No overload for function accepts 0 arguments.", ge->message);
ExtraInformation* ei = get<ExtraInformation>(result.errors[1]);
REQUIRE(ei);
CHECK_EQ("Available overloads: (number) -> number; (number) -> string; and (number, number) -> number", ei->message);
}
TEST_CASE_FIXTURE(Fixture, "dont_give_other_overloads_message_if_only_one_argument_matching_overload_exists")
{
CheckResult result = check(R"(
local multiply: ((number)->number) & ((number)->string) & ((number, number)->number)
multiply(1, "")
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
TypeMismatch* tm = get<TypeMismatch>(result.errors[0]);
REQUIRE(tm);
CHECK_EQ(builtinTypes->numberType, tm->wantedType);
CHECK_EQ(builtinTypes->stringType, tm->givenType);
}
TEST_CASE_FIXTURE(Fixture, "infer_return_type_from_selected_overload")
{
CheckResult result = check(R"(
type T = {method: ((T, number) -> number) & ((number) -> string)}
local T: T
local a = T.method(T, 4)
local b = T.method(5)
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("number", toString(requireType("a")));
CHECK_EQ("string", toString(requireType("b")));
}
TEST_CASE_FIXTURE(Fixture, "too_many_arguments")
{
CheckResult result = check(R"(
--!nonstrict
function g(a: number) end
g()
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
auto err = result.errors[0];
auto acm = get<CountMismatch>(err);
REQUIRE(acm);
CHECK_EQ(1, acm->expected);
CHECK_EQ(0, acm->actual);
}
TEST_CASE_FIXTURE(Fixture, "too_many_arguments_error_location")
{
CheckResult result = check(R"(
--!strict
function myfunction(a: number, b:number) end
myfunction(1)
function getmyfunction()
return myfunction
end
getmyfunction()()
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
{
TypeError err = result.errors[0];
// Ensure the location matches the location of the function identifier
CHECK_EQ(err.location, Location(Position(4, 8), Position(4, 18)));
auto acm = get<CountMismatch>(err);
REQUIRE(acm);
CHECK_EQ(2, acm->expected);
CHECK_EQ(1, acm->actual);
}
{
TypeError err = result.errors[1];
// Ensure the location matches the location of the expression returning the function
CHECK_EQ(err.location, Location(Position(9, 8), Position(9, 23)));
auto acm = get<CountMismatch>(err);
REQUIRE(acm);
CHECK_EQ(2, acm->expected);
CHECK_EQ(0, acm->actual);
}
}
TEST_CASE_FIXTURE(Fixture, "recursive_function")
{
CheckResult result = check(R"(
function count(n: number)
if n == 0 then
return 0
else
return count(n - 1)
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "lambda_form_of_local_function_cannot_be_recursive")
{
CheckResult result = check(R"(
local f = function() return f() end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
}
TEST_CASE_FIXTURE(Fixture, "recursive_local_function")
{
CheckResult result = check(R"(
local function count(n: number)
if n == 0 then
return 0
else
return count(n - 1)
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
// FIXME: This and the above case get handled very differently. It's pretty dumb.
// We really should unify the two code paths, probably by deleting AstStatFunction.
TEST_CASE_FIXTURE(Fixture, "another_recursive_local_function")
{
CheckResult result = check(R"(
local count
function count(n: number)
if n == 0 then
return 0
else
return count(n - 1)
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
// We had a bug where we'd look up the type of a recursive call using the DFG,
// not the bindings tables. As a result, we would erroneously use the
// generalized type of foo() in this recursive fragment. This creates a
// constraint cycle that doesn't always work itself out.
//
// The fix is for the DFG node within the scope of foo() to retain the
// ungeneralized type of foo.
TEST_CASE_FIXTURE(BuiltinsFixture, "recursive_calls_must_refer_to_the_ungeneralized_type")
{
CheckResult result = check(R"(
function foo()
string.format('%s: %s', "51", foo())
end
)");
}
TEST_CASE_FIXTURE(Fixture, "cyclic_function_type_in_rets")
{
CheckResult result = check(R"(
function f()
return f
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("t1 where t1 = () -> t1", toString(requireType("f")));
}
TEST_CASE_FIXTURE(Fixture, "another_higher_order_function")
{
CheckResult result = check(R"(
local Get_des
function Get_des(func)
Get_des(func)
end
local function f(d)
d:IsA("BasePart")
d.Parent:FindFirstChild("Humanoid")
d:IsA("Decal")
end
Get_des(f)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "another_other_higher_order_function")
{
CheckResult result = check(R"(
local d
d:foo()
d:foo()
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "local_function")
{
CheckResult result = check(R"(
function f()
return 8
end
function g()
local function f()
return 'hello'
end
return f
end
local h = g()
)");
LUAU_REQUIRE_NO_ERRORS(result);
TypeId h = follow(requireType("h"));
const FunctionType* ftv = get<FunctionType>(h);
REQUIRE(ftv != nullptr);
std::optional<TypeId> rt = first(ftv->retTypes);
REQUIRE(bool(rt));
TypeId retType = follow(*rt);
CHECK_EQ(PrimitiveType::String, getPrimitiveType(retType));
}
TEST_CASE_FIXTURE(Fixture, "func_expr_doesnt_leak_free")
{
CheckResult result = check(R"(
local p = function(x) return x end
)");
LUAU_REQUIRE_NO_ERRORS(result);
const Luau::FunctionType* fn = get<FunctionType>(requireType("p"));
REQUIRE(fn);
auto ret = first(fn->retTypes);
REQUIRE(ret);
REQUIRE(get<GenericType>(follow(*ret)));
}
TEST_CASE_FIXTURE(Fixture, "first_argument_can_be_optional")
{
CheckResult result = check(R"(
local T = {}
function T.new(a: number?, b: number?, c: number?) return 5 end
local m = T.new()
)");
LUAU_REQUIRE_NO_ERRORS(result);
dumpErrors(result);
}
TEST_CASE_FIXTURE(Fixture, "it_is_ok_not_to_supply_enough_retvals")
{
CheckResult result = check(R"(
function get_two() return 5, 6 end
local a = get_two()
)");
LUAU_REQUIRE_NO_ERRORS(result);
dumpErrors(result);
}
TEST_CASE_FIXTURE(Fixture, "duplicate_functions2")
{
CheckResult result = check(R"(
function foo() end
function bar()
local function foo() end
end
)");
LUAU_REQUIRE_ERROR_COUNT(0, result);
}
TEST_CASE_FIXTURE(Fixture, "duplicate_functions_allowed_in_nonstrict")
{
CheckResult result = check(R"(
--!nonstrict
function foo() end
function foo() end
function bar()
local function foo() end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "duplicate_functions_with_different_signatures_not_allowed_in_nonstrict")
{
CheckResult result = check(R"(
--!nonstrict
function foo(): number
return 1
end
foo()
function foo(n: number): number
return 2
end
foo()
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
TypeMismatch* tm = get<TypeMismatch>(result.errors[0]);
REQUIRE(tm);
CHECK_EQ("() -> number", toString(tm->wantedType));
CHECK_EQ("(number) -> number", toString(tm->givenType));
}
TEST_CASE_FIXTURE(Fixture, "complicated_return_types_require_an_explicit_annotation")
{
CheckResult result = check(R"(
local i = 0
function most_of_the_natural_numbers(): number?
if i < 10 then
i = i + 1
return i
else
return nil
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
TypeId ty = requireType("most_of_the_natural_numbers");
const FunctionType* functionType = get<FunctionType>(ty);
REQUIRE_MESSAGE(functionType, "Expected function but got " << toString(ty));
std::optional<TypeId> retType = first(functionType->retTypes);
REQUIRE(retType);
CHECK(get<UnionType>(*retType));
}
TEST_CASE_FIXTURE(Fixture, "infer_higher_order_function")
{
CheckResult result = check(R"(
function apply(f, x)
return f(x)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
const FunctionType* ftv = get<FunctionType>(requireType("apply"));
REQUIRE(ftv != nullptr);
std::vector<TypeId> argVec = flatten(ftv->argTypes).first;
REQUIRE_EQ(2, argVec.size());
const FunctionType* fType = get<FunctionType>(follow(argVec[0]));
REQUIRE_MESSAGE(fType != nullptr, "Expected a function but got " << toString(argVec[0]));
std::vector<TypeId> fArgs = flatten(fType->argTypes).first;
TypeId xType = follow(argVec[1]);
CHECK_EQ(1, fArgs.size());
CHECK_EQ(xType, follow(fArgs[0]));
}
TEST_CASE_FIXTURE(Fixture, "higher_order_function_2")
{
CheckResult result = check(R"(
function bottomupmerge(comp, a, b, left, mid, right)
local i, j = left, mid
for k = left, right do
if i < mid and (j > right or not comp(a[j], a[i])) then
b[k] = a[i]
i = i + 1
else
b[k] = a[j]
j = j + 1
end
end
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
const FunctionType* ftv = get<FunctionType>(requireType("bottomupmerge"));
REQUIRE(ftv != nullptr);
std::vector<TypeId> argVec = flatten(ftv->argTypes).first;
REQUIRE_EQ(6, argVec.size());
const FunctionType* fType = get<FunctionType>(follow(argVec[0]));
REQUIRE(fType != nullptr);
}
TEST_CASE_FIXTURE(Fixture, "higher_order_function_3")
{
CheckResult result = check(R"(
function swap(p)
local t = p[0]
p[0] = p[1]
p[1] = t
return nil
end
function swapTwice(p)
swap(p)
swap(p)
return p
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
const FunctionType* ftv = get<FunctionType>(requireType("swapTwice"));
REQUIRE(ftv != nullptr);
std::vector<TypeId> argVec = flatten(ftv->argTypes).first;
REQUIRE_EQ(1, argVec.size());
const TableType* argType = get<TableType>(follow(argVec[0]));
REQUIRE(argType != nullptr);
CHECK(bool(argType->indexer));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "higher_order_function_4")
{
CheckResult result = check(R"(
function bottomupmerge(comp, a, b, left, mid, right)
local i, j = left, mid
for k = left, right do
if i < mid and (j > right or not comp(a[j], a[i])) then
b[k] = a[i]
i = i + 1
else
b[k] = a[j]
j = j + 1
end
end
end
function mergesort(arr, comp)
local work = {}
for i = 1, #arr do
work[i] = arr[i]
end
local width = 1
while width < #arr do
for i = 1, #arr, 2*width do
bottomupmerge(comp, arr, work, i, math.min(i+width, #arr), math.min(i+2*width-1, #arr))
end
local temp = work
work = arr
arr = temp
width = width * 2
end
return arr
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
/*
* mergesort takes two arguments: an array of some type T and a function that takes two Ts.
* We must assert that these two types are in fact the same type.
* In other words, comp(arr[x], arr[y]) is well-typed.
*/
const FunctionType* ftv = get<FunctionType>(requireType("mergesort"));
REQUIRE(ftv != nullptr);
std::vector<TypeId> argVec = flatten(ftv->argTypes).first;
REQUIRE_EQ(2, argVec.size());
const TableType* arg0 = get<TableType>(follow(argVec[0]));
REQUIRE(arg0 != nullptr);
REQUIRE(bool(arg0->indexer));
const FunctionType* arg1 = get<FunctionType>(follow(argVec[1]));
REQUIRE(arg1 != nullptr);
REQUIRE_EQ(2, size(arg1->argTypes));
std::vector<TypeId> arg1Args = flatten(arg1->argTypes).first;
CHECK_EQ(*arg0->indexer->indexResultType, *arg1Args[0]);
CHECK_EQ(*arg0->indexer->indexResultType, *arg1Args[1]);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "mutual_recursion")
{
CheckResult result = check(R"(
--!strict
function newPlayerCharacter()
startGui() -- Unknown symbol 'startGui'
end
local characterAddedConnection: any
function startGui()
characterAddedConnection = game:GetService("Players").LocalPlayer.CharacterAdded:connect(newPlayerCharacter)
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
dumpErrors(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "toposort_doesnt_break_mutual_recursion")
{
CheckResult result = check(R"(
--!strict
local x = nil
function f() g() end
-- make sure print(x) doesn't get toposorted here, breaking the mutual block
function g() x = f end
print(x)
)");
LUAU_REQUIRE_NO_ERRORS(result);
dumpErrors(result);
}
TEST_CASE_FIXTURE(Fixture, "check_function_before_lambda_that_uses_it")
{
CheckResult result = check(R"(
--!nonstrict
function f()
return 114
end
return function()
return f():andThen()
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "it_is_ok_to_oversaturate_a_higher_order_function_argument")
{
CheckResult result = check(R"(
function onerror() end
function foo() end
xpcall(foo, onerror)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "another_indirect_function_case_where_it_is_ok_to_provide_too_many_arguments")
{
CheckResult result = check(R"(
local mycb: (number, number) -> ()
function f() end
mycb = f
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "report_exiting_without_return_nonstrict")
{
CheckResult result = check(R"(
--!nonstrict
local function f1(v): number?
if v then
return 1
end
end
local function f2(v)
if v then
return 1
end
end
local function f3(v): ()
if v then
return
end
end
local function f4(v)
if v then
return
end
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
FunctionExitsWithoutReturning* err = get<FunctionExitsWithoutReturning>(result.errors[0]);
CHECK(err);
}
TEST_CASE_FIXTURE(Fixture, "report_exiting_without_return_strict")
{
CheckResult result = check(R"(
--!strict
local function f1(v): number?
if v then
return 1
end
end
local function f2(v)
if v then
return 1
end
end
local function f3(v): ()
if v then
return
end
end
local function f4(v)
if v then
return
end
end
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
FunctionExitsWithoutReturning* annotatedErr = get<FunctionExitsWithoutReturning>(result.errors[0]);
CHECK(annotatedErr);
FunctionExitsWithoutReturning* inferredErr = get<FunctionExitsWithoutReturning>(result.errors[1]);
CHECK(inferredErr);
}
TEST_CASE_FIXTURE(Fixture, "calling_function_with_incorrect_argument_type_yields_errors_spanning_argument")
{
CheckResult result = check(R"(
function foo(a: number, b: string) end
foo("Test", 123)
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
CHECK_EQ(result.errors[0], (TypeError{Location{Position{3, 12}, Position{3, 18}}, TypeMismatch{
builtinTypes->numberType,
builtinTypes->stringType,
}}));
CHECK_EQ(result.errors[1], (TypeError{Location{Position{3, 20}, Position{3, 23}}, TypeMismatch{
builtinTypes->stringType,
builtinTypes->numberType,
}}));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "calling_function_with_anytypepack_doesnt_leak_free_types")
{
CheckResult result = check(R"(
--!nonstrict
function Test(a)
return 1, ""
end
local tab = {}
table.insert(tab, Test(1));
)");
LUAU_REQUIRE_NO_ERRORS(result);
ToStringOptions opts;
opts.exhaustive = true;
opts.maxTableLength = 0;
CHECK_EQ("{any}", toString(requireType("tab"), opts));
}
TEST_CASE_FIXTURE(Fixture, "too_many_return_values")
{
CheckResult result = check(R"(
--!strict
function f()
return 55
end
local a, b = f()
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CountMismatch* acm = get<CountMismatch>(result.errors[0]);
REQUIRE(acm);
CHECK_EQ(acm->context, CountMismatch::FunctionResult);
CHECK_EQ(acm->expected, 1);
CHECK_EQ(acm->actual, 2);
}
TEST_CASE_FIXTURE(Fixture, "too_many_return_values_in_parentheses")
{
CheckResult result = check(R"(
--!strict
function f()
return 55
end
local a, b = (f())
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CountMismatch* acm = get<CountMismatch>(result.errors[0]);
REQUIRE(acm);
CHECK_EQ(acm->context, CountMismatch::FunctionResult);
CHECK_EQ(acm->expected, 1);
CHECK_EQ(acm->actual, 2);
}
TEST_CASE_FIXTURE(Fixture, "too_many_return_values_no_function")
{
CheckResult result = check(R"(
--!strict
local a, b = 55
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CountMismatch* acm = get<CountMismatch>(result.errors[0]);
REQUIRE(acm);
CHECK_EQ(acm->context, CountMismatch::ExprListResult);
CHECK_EQ(acm->expected, 1);
CHECK_EQ(acm->actual, 2);
}
TEST_CASE_FIXTURE(Fixture, "ignored_return_values")
{
CheckResult result = check(R"(
--!strict
function f()
return 55, ""
end
local a = f()
)");
LUAU_REQUIRE_ERROR_COUNT(0, result);
}
TEST_CASE_FIXTURE(Fixture, "function_does_not_return_enough_values")
{
CheckResult result = check(R"(
--!strict
function f(): (number, string)
return 55
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CountMismatch* acm = get<CountMismatch>(result.errors[0]);
REQUIRE(acm);
CHECK_EQ(acm->context, CountMismatch::Return);
CHECK_EQ(acm->expected, 2);
CHECK_EQ(acm->actual, 1);
}
TEST_CASE_FIXTURE(Fixture, "function_cast_error_uses_correct_language")
{
CheckResult result = check(R"(
function foo(a, b): number
return 0
end
local a: (string)->number = foo
local b: (number, number)->(number, number) = foo
local c: (string, number)->number = foo -- no error
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
auto tm1 = get<TypeMismatch>(result.errors[0]);
REQUIRE(tm1);
CHECK_EQ("(string) -> number", toString(tm1->wantedType));
CHECK_EQ("(string, *error-type*) -> number", toString(tm1->givenType));
auto tm2 = get<TypeMismatch>(result.errors[1]);
REQUIRE(tm2);
CHECK_EQ("(number, number) -> (number, number)", toString(tm2->wantedType));
CHECK_EQ("(string, *error-type*) -> number", toString(tm2->givenType));
}
TEST_CASE_FIXTURE(Fixture, "no_lossy_function_type")
{
CheckResult result = check(R"(
--!strict
local tbl = {}
function tbl:abc(a: number, b: number)
return a
end
tbl:abc(1, 2) -- Line 6
-- | Column 14
)");
LUAU_REQUIRE_NO_ERRORS(result);
TypeId type = requireTypeAtPosition(Position(6, 14));
CHECK_EQ("(tbl, number, number) -> number", toString(type));
auto ftv = get<FunctionType>(follow(type));
REQUIRE(ftv);
CHECK(ftv->hasSelf);
}
TEST_CASE_FIXTURE(Fixture, "record_matching_overload")
{
CheckResult result = check(R"(
type Overload = ((string) -> string) & ((number) -> number)
local abc: Overload
abc(1)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// AstExprCall is the node that has the overload stored on it.
// findTypeAtPosition will look at the AstExprLocal, but this is not what
// we want to look at.
std::vector<AstNode*> ancestry = findAstAncestryOfPosition(*getMainSourceModule(), Position(3, 10));
REQUIRE_GE(ancestry.size(), 2);
AstExpr* parentExpr = ancestry[ancestry.size() - 2]->asExpr();
REQUIRE(bool(parentExpr));
REQUIRE(parentExpr->is<AstExprCall>());
ModulePtr module = getMainModule();
auto it = module->astOverloadResolvedTypes.find(parentExpr);
REQUIRE(it);
CHECK_EQ(toString(*it), "(number) -> number");
}
TEST_CASE_FIXTURE(Fixture, "return_type_by_overload")
{
CheckResult result = check(R"(
type Overload = ((string) -> string) & ((number, number) -> number)
local abc: Overload
local x = abc(true)
local y = abc(true,true)
local z = abc(true,true,true)
)");
LUAU_REQUIRE_ERRORS(result);
CHECK_EQ("string", toString(requireType("x")));
CHECK_EQ("number", toString(requireType("y")));
// Should this be string|number?
CHECK_EQ("string", toString(requireType("z")));
}
TEST_CASE_FIXTURE(BuiltinsFixture, "infer_anonymous_function_arguments")
{
// Simple direct arg to arg propagation
CheckResult result = check(R"(
type Table = { x: number, y: number }
local function f(a: (Table) -> number) return a({x = 1, y = 2}) end
f(function(a) return a.x + a.y end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// An optional function is accepted, but since we already provide a function, nil can be ignored
result = check(R"(
type Table = { x: number, y: number }
local function f(a: ((Table) -> number)?) if a then return a({x = 1, y = 2}) else return 0 end end
f(function(a) return a.x + a.y end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Make sure self calls match correct index
result = check(R"(
type Table = { x: number, y: number }
local x = {}
x.b = {x = 1, y = 2}
function x:f(a: (Table) -> number) return a(self.b) end
x:f(function(a) return a.x + a.y end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Mix inferred and explicit argument types
result = check(R"(
function f(a: (a: number, b: number, c: boolean) -> number) return a(1, 2, true) end
f(function(a: number, b, c) return c and a + b or b - a end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Anonymous function has a variadic pack
result = check(R"(
type Table = { x: number, y: number }
local function f(a: (Table) -> number) return a({x = 1, y = 2}) end
f(function(...) return select(1, ...).z end)
)");
LUAU_REQUIRE_ERRORS(result);
CHECK_EQ("Key 'z' not found in table 'Table'", toString(result.errors[0]));
// Can't accept more arguments than provided
result = check(R"(
function f(a: (a: number, b: number) -> number) return a(1, 2) end
f(function(a, b, c, ...) return a + b end)
)");
LUAU_REQUIRE_ERRORS(result);
if (FFlag::LuauInstantiateInSubtyping)
{
CHECK_EQ(R"(Type '<a>(number, number, a) -> number' could not be converted into '(number, number) -> number'
caused by:
Argument count mismatch. Function expects 3 arguments, but only 2 are specified)",
toString(result.errors[0]));
}
else
{
CHECK_EQ(R"(Type '(number, number, a) -> number' could not be converted into '(number, number) -> number'
caused by:
Argument count mismatch. Function expects 3 arguments, but only 2 are specified)",
toString(result.errors[0]));
}
// Infer from variadic packs into elements
result = check(R"(
function f(a: (...number) -> number) return a(1, 2) end
f(function(a, b) return a + b end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Infer from variadic packs into variadic packs
result = check(R"(
type Table = { x: number, y: number }
function f(a: (...Table) -> number) return a({x = 1, y = 2}, {x = 3, y = 4}) end
f(function(a, ...) local b = ... return b.z end)
)");
LUAU_REQUIRE_ERRORS(result);
CHECK_EQ("Key 'z' not found in table 'Table'", toString(result.errors[0]));
// Return type inference
result = check(R"(
type Table = { x: number, y: number }
function f(a: (number) -> Table) return a(4) end
f(function(x) return x * 2 end)
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ("Type 'number' could not be converted into 'Table'", toString(result.errors[0]));
// Return type doesn't inference 'nil'
result = check(R"(
function f(a: (number) -> nil) return a(4) end
f(function(x) print(x) end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "infer_anonymous_function_arguments")
{
// Simple direct arg to arg propagation
CheckResult result = check(R"(
type Table = { x: number, y: number }
local function f(a: (Table) -> number) return a({x = 1, y = 2}) end
f(function(a) return a.x + a.y end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// An optional function is accepted, but since we already provide a function, nil can be ignored
result = check(R"(
type Table = { x: number, y: number }
local function f(a: ((Table) -> number)?) if a then return a({x = 1, y = 2}) else return 0 end end
f(function(a) return a.x + a.y end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Make sure self calls match correct index
result = check(R"(
type Table = { x: number, y: number }
local x = {}
x.b = {x = 1, y = 2}
function x:f(a: (Table) -> number) return a(self.b) end
x:f(function(a) return a.x + a.y end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Mix inferred and explicit argument types
result = check(R"(
function f(a: (a: number, b: number, c: boolean) -> number) return a(1, 2, true) end
f(function(a: number, b, c) return c and a + b or b - a end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Anonymous function has a variadic pack
result = check(R"(
type Table = { x: number, y: number }
local function f(a: (Table) -> number) return a({x = 1, y = 2}) end
f(function(...) return select(1, ...).z end)
)");
LUAU_REQUIRE_ERRORS(result);
CHECK_EQ("Key 'z' not found in table 'Table'", toString(result.errors[0]));
// Can't accept more arguments than provided
result = check(R"(
function f(a: (a: number, b: number) -> number) return a(1, 2) end
f(function(a, b, c, ...) return a + b end)
)");
LUAU_REQUIRE_ERRORS(result);
if (FFlag::LuauInstantiateInSubtyping)
{
CHECK_EQ(R"(Type '<a>(number, number, a) -> number' could not be converted into '(number, number) -> number'
caused by:
Argument count mismatch. Function expects 3 arguments, but only 2 are specified)",
toString(result.errors[0]));
}
else
{
CHECK_EQ(R"(Type '(number, number, a) -> number' could not be converted into '(number, number) -> number'
caused by:
Argument count mismatch. Function expects 3 arguments, but only 2 are specified)",
toString(result.errors[0]));
}
// Infer from variadic packs into elements
result = check(R"(
function f(a: (...number) -> number) return a(1, 2) end
f(function(a, b) return a + b end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
// Infer from variadic packs into variadic packs
result = check(R"(
type Table = { x: number, y: number }
function f(a: (...Table) -> number) return a({x = 1, y = 2}, {x = 3, y = 4}) end
f(function(a, ...) local b = ... return b.z end)
)");
LUAU_REQUIRE_ERRORS(result);
CHECK_EQ("Key 'z' not found in table 'Table'", toString(result.errors[0]));
// Return type inference
result = check(R"(
type Table = { x: number, y: number }
function f(a: (number) -> Table) return a(4) end
f(function(x) return x * 2 end)
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ("Type 'number' could not be converted into 'Table'", toString(result.errors[0]));
// Return type doesn't inference 'nil'
result = check(R"(
function f(a: (number) -> nil) return a(4) end
f(function(x) print(x) end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "variadic_any_is_compatible_with_a_generic_TypePack")
{
ScopedFastFlag sff[] = {
{"LuauVariadicAnyCanBeGeneric", true}
};
CheckResult result = check(R"(
--!strict
local function f(...) return ... end
local g = function(...) return f(...) end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
// https://github.com/Roblox/luau/issues/767
TEST_CASE_FIXTURE(BuiltinsFixture, "variadic_any_is_compatible_with_a_generic_TypePack_2")
{
ScopedFastFlag sff{"LuauVariadicAnyCanBeGeneric", true};
CheckResult result = check(R"(
local function somethingThatsAny(...: any)
print(...)
end
local function x<T...>(...: T...)
somethingThatsAny(...) -- Failed to unify variadic type packs
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "infer_anonymous_function_arguments_outside_call")
{
CheckResult result = check(R"(
type Table = { x: number, y: number }
local f: (Table) -> number = function(t) return t.x + t.y end
type TableWithFunc = { x: number, y: number, f: (number, number) -> number }
local a: TableWithFunc = { x = 3, y = 4, f = function(a, b) return a + b end }
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "infer_return_value_type")
{
CheckResult result = check(R"(
local function f(): {string|number}
return {1, "b", 3}
end
local function g(): (number, {string|number})
return 4, {1, "b", 3}
end
local function h(): ...{string|number}
return {4}, {1, "b", 3}, {"s"}
end
local function i(): ...{string|number}
return {1, "b", 3}, h()
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_arg_count")
{
CheckResult result = check(R"(
type A = (number, number) -> string
type B = (number) -> string
local a: A
local b: B = a
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]), R"(Type '(number, number) -> string' could not be converted into '(number) -> string'
caused by:
Argument count mismatch. Function expects 2 arguments, but only 1 is specified)");
}
TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_arg")
{
CheckResult result = check(R"(
type A = (number, number) -> string
type B = (number, string) -> string
local a: A
local b: B = a
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]), R"(Type '(number, number) -> string' could not be converted into '(number, string) -> string'
caused by:
Argument #2 type is not compatible. Type 'string' could not be converted into 'number')");
}
TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_ret_count")
{
CheckResult result = check(R"(
type A = (number, number) -> (number)
type B = (number, number) -> (number, boolean)
local a: A
local b: B = a
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]), R"(Type '(number, number) -> number' could not be converted into '(number, number) -> (number, boolean)'
caused by:
Function only returns 1 value, but 2 are required here)");
}
TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_ret")
{
CheckResult result = check(R"(
type A = (number, number) -> string
type B = (number, number) -> number
local a: A
local b: B = a
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]), R"(Type '(number, number) -> string' could not be converted into '(number, number) -> number'
caused by:
Return type is not compatible. Type 'string' could not be converted into 'number')");
}
TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_ret_mult")
{
CheckResult result = check(R"(
type A = (number, number) -> (number, string)
type B = (number, number) -> (number, boolean)
local a: A
local b: B = a
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]),
R"(Type '(number, number) -> (number, string)' could not be converted into '(number, number) -> (number, boolean)'
caused by:
Return #2 type is not compatible. Type 'string' could not be converted into 'boolean')");
}
TEST_CASE_FIXTURE(BuiltinsFixture, "function_decl_quantify_right_type")
{
fileResolver.source["game/isAMagicMock"] = R"(
--!nonstrict
return function(value)
return false
end
)";
CheckResult result = check(R"(
--!nonstrict
local MagicMock = {}
MagicMock.is = require(game.isAMagicMock)
function MagicMock.is(value)
return false
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "function_decl_non_self_sealed_overwrite")
{
CheckResult result = check(R"(
function string.len(): number
return 1
end
local s = string
)");
LUAU_REQUIRE_NO_ERRORS(result);
// if 'string' library property was replaced with an internal module type, it will be freed and the next check will crash
frontend.clear();
CheckResult result2 = check(R"(
print(string.len('hello'))
)");
LUAU_REQUIRE_NO_ERRORS(result2);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "function_decl_non_self_sealed_overwrite_2")
{
CheckResult result = check(R"(
local t: { f: ((x: number) -> number)? } = {}
function t.f(x)
print(x + 5)
return x .. "asd" -- 1st error: we know that return type is a number, not a string
end
t.f = function(x)
print(x + 5)
return x .. "asd" -- 2nd error: we know that return type is a number, not a string
end
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
CHECK_EQ(toString(result.errors[0]), R"(Type 'string' could not be converted into 'number')");
CHECK_EQ(toString(result.errors[1]), R"(Type 'string' could not be converted into 'number')");
}
TEST_CASE_FIXTURE(Fixture, "inferred_higher_order_functions_are_quantified_at_the_right_time2")
{
CheckResult result = check(R"(
--!strict
local function resolveDispatcher()
return (nil :: any) :: {useContext: (number?) -> any}
end
local useContext
useContext = function(unstable_observedBits: number?)
resolveDispatcher().useContext(unstable_observedBits)
end
)");
// LUAU_REQUIRE_NO_ERRORS is particularly unhelpful when this test is broken.
// You get a TypeMismatch error where both types stringify the same.
CHECK(result.errors.empty());
if (!result.errors.empty())
{
for (const auto& e : result.errors)
printf("%s %s: %s\n", e.moduleName.c_str(), toString(e.location).c_str(), toString(e).c_str());
}
}
TEST_CASE_FIXTURE(Fixture, "inferred_higher_order_functions_are_quantified_at_the_right_time3")
{
CheckResult result = check(R"(
local foo
foo():bar(function()
return foo()
end)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "function_decl_non_self_unsealed_overwrite")
{
CheckResult result = check(R"(
local t = { f = nil :: ((x: number) -> number)? }
function t.f(x: string): string -- 1st error: new function value type is incompatible
return x .. "asd"
end
t.f = function(x)
print(x + 5)
return x .. "asd" -- 2nd error: we know that return type is a number, not a string
end
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
CHECK_EQ(toString(result.errors[0]), R"(Type '(string) -> string' could not be converted into '((number) -> number)?'
caused by:
None of the union options are compatible. For example: Type '(string) -> string' could not be converted into '(number) -> number'
caused by:
Argument #1 type is not compatible. Type 'number' could not be converted into 'string')");
CHECK_EQ(toString(result.errors[1]), R"(Type 'string' could not be converted into 'number')");
}
TEST_CASE_FIXTURE(Fixture, "strict_mode_ok_with_missing_arguments")
{
CheckResult result = check(R"(
local function f(x: any) end
f()
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "function_statement_sealed_table_assignment_through_indexer")
{
CheckResult result = check(R"(
local t: {[string]: () -> number} = {}
function t.a() return 1 end -- OK
function t:b() return 2 end -- not OK
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(R"(Type '(*error-type*) -> number' could not be converted into '() -> number'
caused by:
Argument count mismatch. Function expects 1 argument, but none are specified)",
toString(result.errors[0]));
}
TEST_CASE_FIXTURE(Fixture, "too_few_arguments_variadic")
{
CheckResult result = check(R"(
function test(a: number, b: string, ...)
end
test(1)
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
auto err = result.errors[0];
auto acm = get<CountMismatch>(err);
REQUIRE(acm);
CHECK_EQ(2, acm->expected);
CHECK_EQ(1, acm->actual);
CHECK_EQ(CountMismatch::Context::Arg, acm->context);
CHECK(acm->isVariadic);
}
TEST_CASE_FIXTURE(Fixture, "too_few_arguments_variadic_generic")
{
CheckResult result = check(R"(
function test(a: number, b: string, ...)
return 1
end
function wrapper<A...>(f: (A...) -> number, ...: A...)
end
wrapper(test)
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
auto err = result.errors[0];
auto acm = get<CountMismatch>(err);
REQUIRE(acm);
CHECK_EQ(3, acm->expected);
CHECK_EQ(1, acm->actual);
CHECK_EQ(CountMismatch::Context::Arg, acm->context);
CHECK(acm->isVariadic);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "too_few_arguments_variadic_generic2")
{
CheckResult result = check(R"(
function test(a: number, b: string, ...)
return 1
end
function wrapper<A...>(f: (A...) -> number, ...: A...)
end
pcall(wrapper, test)
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
auto err = result.errors[0];
auto acm = get<CountMismatch>(err);
REQUIRE(acm);
CHECK_EQ(4, acm->expected);
CHECK_EQ(2, acm->actual);
CHECK_EQ(CountMismatch::Context::Arg, acm->context);
CHECK(acm->isVariadic);
}
TEST_CASE_FIXTURE(Fixture, "occurs_check_failure_in_function_return_type")
{
CheckResult result = check(R"(
function f()
return 5, f()
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK(nullptr != get<OccursCheckFailed>(result.errors[0]));
}
TEST_CASE_FIXTURE(Fixture, "free_is_not_bound_to_unknown")
{
CheckResult result = check(R"(
local function foo(f: (unknown) -> (), x)
f(x)
end
)");
CHECK_EQ("<a>((unknown) -> (), a) -> ()", toString(requireType("foo")));
}
TEST_CASE_FIXTURE(Fixture, "dont_infer_parameter_types_for_functions_from_their_call_site")
{
CheckResult result = check(R"(
local t = {}
function t.f(x)
return x
end
t.__index = t
function g(s)
local q = s.p and s.p.q or nil
return q and t.f(q) or nil
end
local f = t.f
)");
LUAU_REQUIRE_NO_ERRORS(result);
CHECK_EQ("<a>(a) -> a", toString(requireType("f")));
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK_EQ("<a>({+ p: {+ q: a +} +}) -> a & ~false", toString(requireType("g")));
else
CHECK_EQ("({+ p: {+ q: nil +} +}) -> nil", toString(requireType("g")));
}
TEST_CASE_FIXTURE(Fixture, "dont_mutate_the_underlying_head_of_typepack_when_calling_with_self")
{
CheckResult result = check(R"(
local t = {}
function t:m(x) end
function f(): never return 5 :: never end
t:m(f())
t:m(f())
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "improved_function_arg_mismatch_errors")
{
CheckResult result = check(R"(
local function foo1(a: number) end
foo1()
local function foo2(a: number, b: string?) end
foo2()
local function foo3(a: number, b: string?, c: any) end -- any is optional
foo3()
string.find()
local t = {}
function t.foo(x: number, y: string?, ...: any) return 1 end
function t:bar(x: number, y: string?) end
t.foo()
t:bar()
local u = { a = t, b = function() return t end }
u.a.foo()
local x = (u.a).foo()
u.b().foo()
)");
LUAU_REQUIRE_ERROR_COUNT(9, result);
CHECK_EQ(toString(result.errors[0]), "Argument count mismatch. Function 'foo1' expects 1 argument, but none are specified");
CHECK_EQ(toString(result.errors[1]), "Argument count mismatch. Function 'foo2' expects 1 to 2 arguments, but none are specified");
CHECK_EQ(toString(result.errors[2]), "Argument count mismatch. Function 'foo3' expects 1 to 3 arguments, but none are specified");
CHECK_EQ(toString(result.errors[3]), "Argument count mismatch. Function 'string.find' expects 2 to 4 arguments, but none are specified");
CHECK_EQ(toString(result.errors[4]), "Argument count mismatch. Function 't.foo' expects at least 1 argument, but none are specified");
CHECK_EQ(toString(result.errors[5]), "Argument count mismatch. Function 't.bar' expects 2 to 3 arguments, but only 1 is specified");
CHECK_EQ(toString(result.errors[6]), "Argument count mismatch. Function 'u.a.foo' expects at least 1 argument, but none are specified");
CHECK_EQ(toString(result.errors[7]), "Argument count mismatch. Function 'u.a.foo' expects at least 1 argument, but none are specified");
CHECK_EQ(toString(result.errors[8]), "Argument count mismatch. Function expects at least 1 argument, but none are specified");
}
// This might be surprising, but since 'any' became optional, unannotated functions in non-strict 'expect' 0 arguments
TEST_CASE_FIXTURE(BuiltinsFixture, "improved_function_arg_mismatch_error_nonstrict")
{
CheckResult result = check(R"(
--!nonstrict
local function foo(a, b) end
foo(string.find("hello", "e"))
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]), "Argument count mismatch. Function 'foo' expects 0 to 2 arguments, but 3 are specified");
}
TEST_CASE_FIXTURE(Fixture, "luau_subtyping_is_np_hard")
{
CheckResult result = check(R"(
--!strict
-- An example of coding up graph coloring in the Luau type system.
-- This codes a three-node, two color problem.
-- A three-node triangle is uncolorable,
-- but a three-node line is colorable.
type Red = "red"
type Blue = "blue"
type Color = Red | Blue
type Coloring = (Color) -> (Color) -> (Color) -> boolean
type Uncolorable = (Color) -> (Color) -> (Color) -> false
type Line = Coloring
& ((Red) -> (Red) -> (Color) -> false)
& ((Blue) -> (Blue) -> (Color) -> false)
& ((Color) -> (Red) -> (Red) -> false)
& ((Color) -> (Blue) -> (Blue) -> false)
type Triangle = Line
& ((Red) -> (Color) -> (Red) -> false)
& ((Blue) -> (Color) -> (Blue) -> false)
local x : Triangle
local y : Line
local z : Uncolorable
z = x -- OK, so the triangle is uncolorable
z = y -- Not OK, so the line is colorable
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_EQ(toString(result.errors[0]),
"Type '((\"blue\" | \"red\") -> (\"blue\" | \"red\") -> (\"blue\" | \"red\") -> boolean) & ((\"blue\" | \"red\") -> (\"blue\") -> (\"blue\") "
"-> false) & ((\"blue\" | \"red\") -> (\"red\") -> (\"red\") -> false) & ((\"blue\") -> (\"blue\") -> (\"blue\" | \"red\") -> false) & "
"((\"red\") -> (\"red\") -> (\"blue\" | \"red\") -> false)' could not be converted into '(\"blue\" | \"red\") -> (\"blue\" | \"red\") -> "
"(\"blue\" | \"red\") -> false'; none of the intersection parts are compatible");
}
TEST_CASE_FIXTURE(Fixture, "function_is_supertype_of_concrete_functions")
{
registerHiddenTypes(&frontend);
CheckResult result = check(R"(
function foo(f: fun) end
function a() end
function id(x) return x end
foo(a)
foo(id)
foo(foo)
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "concrete_functions_are_not_supertypes_of_function")
{
registerHiddenTypes(&frontend);
CheckResult result = check(R"(
local a: fun = function() end
function one(arg: () -> ()) end
function two(arg: <T>(T) -> T) end
one(a)
two(a)
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
CHECK(6 == result.errors[0].location.begin.line);
CHECK(7 == result.errors[1].location.begin.line);
}
TEST_CASE_FIXTURE(Fixture, "other_things_are_not_related_to_function")
{
registerHiddenTypes(&frontend);
CheckResult result = check(R"(
local a: fun = function() end
local b: {} = a
local c: boolean = a
local d: fun = true
local e: fun = {}
)");
LUAU_REQUIRE_ERROR_COUNT(4, result);
CHECK(2 == result.errors[0].location.begin.line);
CHECK(3 == result.errors[1].location.begin.line);
CHECK(4 == result.errors[2].location.begin.line);
CHECK(5 == result.errors[3].location.begin.line);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "fuzz_must_follow_in_overload_resolution")
{
CheckResult result = check(R"(
for _ in function<t0>():(t0)&((()->())&(()->()))
end do
_(_(_,_,_),_)
end
)");
LUAU_REQUIRE_ERRORS(result);
}
TEST_CASE_FIXTURE(BuiltinsFixture, "dont_assert_when_the_tarjan_limit_is_exceeded_during_generalization")
{
ScopedFastInt sfi{"LuauTarjanChildLimit", 2};
ScopedFastFlag sff[] = {
{"DebugLuauDeferredConstraintResolution", true},
{"LuauClonePublicInterfaceLess2", true},
{"LuauSubstitutionReentrant", true},
{"LuauSubstitutionFixMissingFields", true},
{"LuauCloneSkipNonInternalVisit", true},
};
CheckResult result = check(R"(
function f(t)
t.x.y.z = 441
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
CHECK_MESSAGE(get<CodeTooComplex>(result.errors[0]), "Expected CodeTooComplex but got: " << toString(result.errors[0]));
CHECK(Location({1, 17}, {1, 18}) == result.errors[0].location);
}
/* We had a bug under DCR where instantiated type packs had a nullptr scope.
*
* This caused an issue with promotion.
*/
TEST_CASE_FIXTURE(Fixture, "instantiated_type_packs_must_have_a_non_null_scope")
{
CheckResult result = check(R"(
function pcall<A..., R...>(...: A...): R...
end
type Dispatch<A> = (A) -> ()
function mountReducer()
dispatchAction()
return nil :: any
end
function dispatchAction()
end
function useReducer(): Dispatch<any>
local result, setResult = pcall(mountReducer)
return setResult
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
}
TEST_CASE_FIXTURE(Fixture, "inner_frees_become_generic_in_dcr")
{
if (!FFlag::DebugLuauDeferredConstraintResolution)
return;
CheckResult result = check(R"(
function f(x)
local z = x
return x
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
std::optional<TypeId> ty = findTypeAtPosition(Position{3, 19});
REQUIRE(ty);
CHECK(get<GenericType>(follow(*ty)));
}
TEST_CASE_FIXTURE(Fixture, "function_exprs_are_generalized_at_signature_scope_not_enclosing")
{
CheckResult result = check(R"(
local foo
local bar
-- foo being a function expression is deliberate: the bug we're testing
-- only existed for function expressions, not for function statements.
foo = function(a)
return bar
end
)");
LUAU_REQUIRE_NO_ERRORS(result);
// note that b is not in the generic list; it is free, the unconstrained type of `bar`.
CHECK(toString(requireType("foo")) == "<a>(a) -> b");
}
TEST_CASE_FIXTURE(BuiltinsFixture, "param_1_and_2_both_takes_the_same_generic_but_their_arguments_are_incompatible")
{
ScopedFastFlag sff{"LuauAlwaysCommitInferencesOfFunctionCalls", true};
CheckResult result = check(R"(
local function foo<a>(x: a, y: a?)
return x
end
local vec2 = { x = 5, y = 7 }
local ret: number = foo(vec2, { x = 5 })
)");
// In the old solver, this produces a very strange result:
//
// Here, we instantiate `<a>(x: a, y: a?) -> a` with a fresh type `'a` for `a`.
// In argument #1, we unify `vec2` with `'a`.
// This is ok, so we record an equality constraint `'a` with `vec2`.
// In argument #2, we unify `{ x: number }` with `'a?`.
// This fails because `'a` has equality constraint with `vec2`,
// so `{ x: number } <: vec2?`, which is false.
//
// If the unifications were to be committed, then it'd result in the following type error:
//
// Type '{ x: number }' could not be converted into 'vec2?'
// caused by:
// [...] Table type '{ x: number }' not compatible with type 'vec2' because the former is missing field 'y'
//
// However, whenever we check the argument list, if there's an error, we don't commit the unifications, so it actually looks like this:
//
// Type '{ x: number }' could not be converted into 'a?'
// caused by:
// [...] Table type '{ x: number }' not compatible with type 'vec2' because the former is missing field 'y'
//
// Then finally, that generic is left floating free, and since the function returns that generic,
// that free type is then later bound to `number`, which succeeds and mutates the type graph.
// This again changes the type error where `a` becomes bound to `number`.
//
// Type '{ x: number }' could not be converted into 'number?'
// caused by:
// [...] Table type '{ x: number }' not compatible with type 'vec2' because the former is missing field 'y'
//
// Uh oh, that type error is extremely confusing for people who doesn't know how that went down.
// Really, what should happen is we roll each argument incompatibility into a union type, but that needs local type inference.
LUAU_REQUIRE_ERROR_COUNT(2, result);
CHECK_EQ(toString(result.errors[0]), R"(Type '{ x: number }' could not be converted into 'vec2?'
caused by:
None of the union options are compatible. For example: Table type '{ x: number }' not compatible with type 'vec2' because the former is missing field 'y')");
CHECK_EQ(toString(result.errors[1]), "Type 'vec2' could not be converted into 'number'");
}
TEST_CASE_FIXTURE(BuiltinsFixture, "param_1_and_2_both_takes_the_same_generic_but_their_arguments_are_incompatible_2")
{
ScopedFastFlag sff{"LuauAlwaysCommitInferencesOfFunctionCalls", true};
CheckResult result = check(R"(
local function f<a>(x: a, y: a): a
return if math.random() > 0.5 then x else y
end
local z: boolean = f(5, "five")
)");
LUAU_REQUIRE_ERROR_COUNT(2, result);
CHECK_EQ(toString(result.errors[0]), "Type 'string' could not be converted into 'number'");
CHECK_EQ(toString(result.errors[1]), "Type 'number' could not be converted into 'boolean'");
}
TEST_CASE_FIXTURE(Fixture, "attempt_to_call_an_intersection_of_tables")
{
CheckResult result = check(R"(
local function f(t: { x: number } & { y: string })
t()
end
)");
LUAU_REQUIRE_ERROR_COUNT(1, result);
if (FFlag::DebugLuauDeferredConstraintResolution)
CHECK_EQ(toString(result.errors[0]), "Cannot call non-function {| x: number |} & {| y: string |}");
else
CHECK_EQ(toString(result.errors[0]), "Cannot call non-function {| x: number |}");
}
TEST_SUITE_END();
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