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501 lines
17 KiB
C++
501 lines
17 KiB
C++
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
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#include "Luau/TypeInfer.h"
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#include "Fixture.h"
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#include "doctest.h"
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#include <algorithm>
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LUAU_FASTFLAG(LuauLowerBoundsCalculation)
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using namespace Luau;
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TEST_SUITE_BEGIN("ProvisionalTests");
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// These tests check for behavior that differs from the final behavior we'd
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// like to have. They serve to document the current state of the typechecker.
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// When making future improvements, its very likely these tests will break and
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// will need to be replaced.
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/*
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* This test falls into a sort of "do as I say" pit of consequences:
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* Technically, the type of the type() function is <T>(T) -> string
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*
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* We thus infer that the argument to f is a free type.
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* While we can still learn something about this argument, we can't seem to infer a union for it.
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*
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* Is this good? Maybe not, but I'm not sure what else we should do.
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*/
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TEST_CASE_FIXTURE(Fixture, "typeguard_inference_incomplete")
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{
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const std::string code = R"(
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function f(a)
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if type(a) == "boolean" then
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local a1 = a
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elseif a.fn() then
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local a2 = a
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end
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end
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)";
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const std::string expected = R"(
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function f(a:{fn:()->(a,b...)}): ()
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if type(a) == 'boolean'then
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local a1:boolean=a
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elseif a.fn()then
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local a2:{fn:()->(a,b...)}=a
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end
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end
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)";
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CHECK_EQ(expected, decorateWithTypes(code));
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}
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TEST_CASE_FIXTURE(BuiltinsFixture, "xpcall_returns_what_f_returns")
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{
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const std::string code = R"(
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local a, b, c = xpcall(function() return 1, "foo" end, function() return "foo", 1 end)
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)";
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const std::string expected = R"(
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local a:boolean,b:number,c:string=xpcall(function(): (number,string)return 1,'foo'end,function(): (string,number)return'foo',1 end)
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)";
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CHECK_EQ(expected, decorateWithTypes(code));
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}
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// We had a bug where if you have two type packs that looks like:
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// { x, y }, ...
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// { x }, ...
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// It would infinitely grow the type pack because one WeirdIter is trying to catch up, but can't.
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// However, the following snippet is supposed to generate an OccursCheckFailed, but it doesn't.
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TEST_CASE_FIXTURE(Fixture, "weirditer_should_not_loop_forever")
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{
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// this flag is intentionally here doing nothing to demonstrate that we exit early via case detection
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ScopedFastInt sfis{"LuauTypeInferTypePackLoopLimit", 50};
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CheckResult result = check(R"(
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local function toVertexList(vertices, x, y, ...)
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if not (x and y) then return vertices end -- no more arguments
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vertices[#vertices + 1] = {x = x, y = y} -- set vertex
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return toVertexList(vertices, ...) -- recurse
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end
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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}
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// This should also generate an OccursCheckFailed error too, like the above toVertexList snippet.
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// at least up until we can get Luau to recognize this code as a valid function that iterates over a list of values in the pack.
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TEST_CASE_FIXTURE(Fixture, "it_should_be_agnostic_of_actual_size")
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{
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CheckResult result = check(R"(
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local function f(x, y, ...)
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if not y then return x end
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return f(x, ...)
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end
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f(3, 2, 1, 0)
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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}
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// Ideally setmetatable's second argument would be an optional free table.
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// For now, infer it as just a free table.
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TEST_CASE_FIXTURE(BuiltinsFixture, "setmetatable_constrains_free_type_into_free_table")
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{
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CheckResult result = check(R"(
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local a = {}
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local b
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setmetatable(a, b)
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b = 1
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)");
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LUAU_REQUIRE_ERROR_COUNT(1, result);
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TypeMismatch* tm = get<TypeMismatch>(result.errors[0]);
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REQUIRE(tm);
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CHECK_EQ("{- -}", toString(tm->wantedType));
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CHECK_EQ("number", toString(tm->givenType));
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}
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// Luau currently doesn't yet know how to allow assignments when the binding was refined.
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TEST_CASE_FIXTURE(Fixture, "while_body_are_also_refined")
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{
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CheckResult result = check(R"(
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type Node<T> = { value: T, child: Node<T>? }
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local function visitor<T>(node: Node<T>, f: (T) -> ())
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local current = node
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while current do
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f(current.value)
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current = current.child -- TODO: Can't work just yet. It thinks 'current' can never be nil. :(
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end
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end
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)");
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LUAU_REQUIRE_ERROR_COUNT(1, result);
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CHECK_EQ("Type 'Node<T>?' could not be converted into 'Node<T>'", toString(result.errors[0]));
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}
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// Originally from TypeInfer.test.cpp.
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// I dont think type checking the metamethod at every site of == is the correct thing to do.
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// We should be type checking the metamethod at the call site of setmetatable.
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TEST_CASE_FIXTURE(BuiltinsFixture, "error_on_eq_metamethod_returning_a_type_other_than_boolean")
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{
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CheckResult result = check(R"(
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local tab = {a = 1}
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setmetatable(tab, {__eq = function(a, b): number
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return 1
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end})
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local tab2 = tab
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local a = tab2 == tab
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)");
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LUAU_REQUIRE_ERROR_COUNT(1, result);
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GenericError* ge = get<GenericError>(result.errors[0]);
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REQUIRE(ge);
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CHECK_EQ("Metamethod '__eq' must return type 'boolean'", ge->message);
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}
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// Requires success typing to confidently determine that this expression has no overlap.
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TEST_CASE_FIXTURE(Fixture, "operator_eq_completely_incompatible")
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{
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CheckResult result = check(R"(
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local a: string | number = "hi"
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local b: {x: string}? = {x = "bye"}
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local r1 = a == b
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local r2 = b == a
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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}
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// Belongs in TypeInfer.refinements.test.cpp.
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// We'll need to not only report an error on `a == b`, but also to refine both operands as `never` in the `==` branch.
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TEST_CASE_FIXTURE(Fixture, "lvalue_equals_another_lvalue_with_no_overlap")
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{
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CheckResult result = check(R"(
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local function f(a: string, b: boolean?)
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if a == b then
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local foo, bar = a, b
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else
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local foo, bar = a, b
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end
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end
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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CHECK_EQ(toString(requireTypeAtPosition({3, 33})), "string"); // a == b
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CHECK_EQ(toString(requireTypeAtPosition({3, 36})), "boolean?"); // a == b
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CHECK_EQ(toString(requireTypeAtPosition({5, 33})), "string"); // a ~= b
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CHECK_EQ(toString(requireTypeAtPosition({5, 36})), "boolean?"); // a ~= b
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}
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// Also belongs in TypeInfer.refinements.test.cpp.
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// Just needs to fully support equality refinement. Which is annoying without type states.
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TEST_CASE_FIXTURE(Fixture, "discriminate_from_x_not_equal_to_nil")
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{
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CheckResult result = check(R"(
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type T = {x: string, y: number} | {x: nil, y: nil}
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local function f(t: T)
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if t.x ~= nil then
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local foo = t
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else
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local bar = t
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end
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end
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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CHECK_EQ("{| x: string, y: number |}", toString(requireTypeAtPosition({5, 28})));
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// Should be {| x: nil, y: nil |}
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CHECK_EQ("{| x: nil, y: nil |} | {| x: string, y: number |}", toString(requireTypeAtPosition({7, 28})));
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}
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TEST_CASE_FIXTURE(Fixture, "bail_early_if_unification_is_too_complicated" * doctest::timeout(0.5))
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{
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ScopedFastInt sffi{"LuauTarjanChildLimit", 1};
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ScopedFastInt sffi2{"LuauTypeInferIterationLimit", 1};
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CheckResult result = check(R"LUA(
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local Result
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Result = setmetatable({}, {})
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Result.__index = Result
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function Result.new(okValue)
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local self = setmetatable({}, Result)
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self:constructor(okValue)
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return self
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end
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function Result:constructor(okValue)
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self.okValue = okValue
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end
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function Result:ok(val) return Result.new(val) end
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function Result:a(p0, p1, p2, p3, p4) return Result.new((self.okValue)) or p0 or p1 or p2 or p3 or p4 end
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function Result:b(p0, p1, p2, p3, p4) return Result:ok((self.okValue)) or p0 or p1 or p2 or p3 or p4 end
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function Result:c(p0, p1, p2, p3, p4) return Result:ok((self.okValue)) or p0 or p1 or p2 or p3 or p4 end
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function Result:transpose(a)
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return a and self.okValue:z(function(some)
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return Result:ok(some)
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end) or Result:ok(self.okValue)
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end
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)LUA");
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auto it = std::find_if(result.errors.begin(), result.errors.end(), [](TypeError& a) {
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return nullptr != get<UnificationTooComplex>(a);
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});
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if (it == result.errors.end())
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{
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dumpErrors(result);
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FAIL("Expected a UnificationTooComplex error");
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}
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}
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// Should be in TypeInfer.tables.test.cpp
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// It's unsound to instantiate tables containing generic methods,
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// since mutating properties means table properties should be invariant.
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// We currently allow this but we shouldn't!
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TEST_CASE_FIXTURE(Fixture, "invariant_table_properties_means_instantiating_tables_in_call_is_unsound")
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{
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CheckResult result = check(R"(
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--!strict
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local t = {}
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function t.m(x) return x end
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local a : string = t.m("hi")
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local b : number = t.m(5)
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function f(x : { m : (number)->number })
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x.m = function(x) return 1+x end
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end
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f(t) -- This shouldn't typecheck
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local c : string = t.m("hi")
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)");
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// TODO: this should error!
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// This should be fixed by replacing generic tables by generics with type bounds.
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LUAU_REQUIRE_NO_ERRORS(result);
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}
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// FIXME: Move this test to another source file when removing FFlag::LuauLowerBoundsCalculation
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TEST_CASE_FIXTURE(Fixture, "do_not_ice_when_trying_to_pick_first_of_generic_type_pack")
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{
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ScopedFastFlag sff[]{
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{"LuauReturnAnyInsteadOfICE", true},
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};
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// In-place quantification causes these types to have the wrong types but only because of nasty interaction with prototyping.
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// The type of f is initially () -> free1...
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// Then the prototype iterator advances, and checks the function expression assigned to g, which has the type () -> free2...
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// In the body it calls f and returns what f() returns. This binds free2... with free1..., causing f and g to have same types.
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// We then quantify g, leaving it with the final type <a...>() -> a...
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// Because free1... and free2... were bound, in combination with in-place quantification, f's return type was also turned into a...
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// Then the check iterator catches up, and checks the body of f, and attempts to quantify it too.
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// Alas, one of the requirements for quantification is that a type must contain free types. () -> a... has no free types.
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// Thus the quantification for f was no-op, which explains why f does not have any type parameters.
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// Calling f() will attempt to instantiate the function type, which turns generics in type binders into to free types.
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// However, instantiations only converts generics contained within the type binders of a function, so instantiation was also no-op.
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// Which means that calling f() simply returned a... rather than an instantiation of it. And since the call site was not in tail position,
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// picking first element in a... triggers an ICE because calls returning generic packs are unexpected.
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CheckResult result = check(R"(
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local function f() end
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local g = function() return f() end
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local x = (f()) -- should error: no return values to assign from the call to f
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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if (FFlag::LuauLowerBoundsCalculation)
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{
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CHECK_EQ("() -> ()", toString(requireType("f")));
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CHECK_EQ("() -> ()", toString(requireType("g")));
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CHECK_EQ("nil", toString(requireType("x")));
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}
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else
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{
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// f and g should have the type () -> ()
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CHECK_EQ("() -> (a...)", toString(requireType("f")));
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CHECK_EQ("<a...>() -> (a...)", toString(requireType("g")));
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CHECK_EQ("any", toString(requireType("x"))); // any is returned instead of ICE for now
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}
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}
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TEST_CASE_FIXTURE(Fixture, "specialization_binds_with_prototypes_too_early")
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{
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CheckResult result = check(R"(
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local function id(x) return x end
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local n2n: (number) -> number = id
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local s2s: (string) -> string = id
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)");
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LUAU_REQUIRE_ERRORS(result); // Should not have any errors.
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}
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TEST_CASE_FIXTURE(Fixture, "weird_fail_to_unify_variadic_pack")
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{
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ScopedFastFlag sff[] = {
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{"LuauLowerBoundsCalculation", false},
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};
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CheckResult result = check(R"(
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--!strict
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local function f(...) return ... end
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local g = function(...) return f(...) end
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)");
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LUAU_REQUIRE_ERRORS(result); // Should not have any errors.
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}
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TEST_CASE_FIXTURE(Fixture, "lower_bounds_calculation_is_too_permissive_with_overloaded_higher_order_functions")
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{
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ScopedFastFlag sff[] = {
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{"LuauLowerBoundsCalculation", true},
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};
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CheckResult result = check(R"(
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function foo(f)
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f(5, 'a')
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f('b', 6)
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end
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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// We incorrectly infer that the argument to foo could be called with (number, number) or (string, string)
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// even though that is strictly more permissive than the actual source text shows.
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CHECK("<a...>((number | string, number | string) -> (a...)) -> ()" == toString(requireType("foo")));
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}
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// Once fixed, move this to Normalize.test.cpp
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TEST_CASE_FIXTURE(Fixture, "normalization_fails_on_certain_kinds_of_cyclic_tables")
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{
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#if defined(_DEBUG) || defined(_NOOPT)
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ScopedFastInt sfi("LuauNormalizeIterationLimit", 500);
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#endif
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ScopedFastFlag flags[] = {
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{"LuauLowerBoundsCalculation", true},
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};
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// We use a function and inferred parameter types to prevent intermediate normalizations from being performed.
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// This exposes a bug where the type of y is mutated.
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CheckResult result = check(R"(
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function strange(x, y)
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x.x = y
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y.x = x
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type R = {x: typeof(x)} & {x: typeof(y)}
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local r: R
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return r
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end
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)");
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LUAU_REQUIRE_ERROR_COUNT(1, result);
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CHECK(nullptr != get<NormalizationTooComplex>(result.errors[0]));
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}
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// Belongs in TypeInfer.builtins.test.cpp.
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TEST_CASE_FIXTURE(BuiltinsFixture, "pcall_returns_at_least_two_value_but_function_returns_nothing")
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{
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CheckResult result = check(R"(
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local function f(): () end
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local ok, res = pcall(f)
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)");
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LUAU_REQUIRE_ERROR_COUNT(1, result);
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CHECK_EQ("Function only returns 1 value. 2 are required here", toString(result.errors[0]));
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// LUAU_REQUIRE_NO_ERRORS(result);
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// CHECK_EQ("boolean", toString(requireType("ok")));
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// CHECK_EQ("any", toString(requireType("res")));
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}
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// Belongs in TypeInfer.builtins.test.cpp.
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TEST_CASE_FIXTURE(BuiltinsFixture, "choose_the_right_overload_for_pcall")
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{
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CheckResult result = check(R"(
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local function f(): number
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if math.random() > 0.5 then
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return 5
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else
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error("something")
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end
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end
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local ok, res = pcall(f)
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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CHECK_EQ("boolean", toString(requireType("ok")));
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CHECK_EQ("number", toString(requireType("res")));
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// CHECK_EQ("any", toString(requireType("res")));
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}
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// Belongs in TypeInfer.builtins.test.cpp.
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TEST_CASE_FIXTURE(BuiltinsFixture, "function_returns_many_things_but_first_of_it_is_forgotten")
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{
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CheckResult result = check(R"(
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local function f(): (number, string, boolean)
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if math.random() > 0.5 then
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return 5, "hello", true
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else
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error("something")
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end
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end
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local ok, res, s, b = pcall(f)
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)");
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LUAU_REQUIRE_NO_ERRORS(result);
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CHECK_EQ("boolean", toString(requireType("ok")));
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CHECK_EQ("number", toString(requireType("res")));
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// CHECK_EQ("any", toString(requireType("res")));
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CHECK_EQ("string", toString(requireType("s")));
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CHECK_EQ("boolean", toString(requireType("b")));
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}
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TEST_CASE_FIXTURE(Fixture, "constrained_is_level_dependent")
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{
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ScopedFastFlag sff[]{
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{"LuauLowerBoundsCalculation", true},
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{"LuauNormalizeFlagIsConservative", true},
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};
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CheckResult result = check(R"(
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local function f(o)
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local t = {}
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t[o] = true
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local function foo(o)
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o:m1()
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t[o] = nil
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end
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local function bar(o)
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o:m2()
|
|
t[o] = true
|
|
end
|
|
|
|
return t
|
|
end
|
|
)");
|
|
|
|
LUAU_REQUIRE_NO_ERRORS(result);
|
|
// TODO: We're missing generics a... and b...
|
|
CHECK_EQ("(t1) -> {| [t1]: boolean |} where t1 = t2 ; t2 = {+ m1: (t1) -> (a...), m2: (t2) -> (b...) +}", toString(requireType("f")));
|
|
}
|
|
|
|
TEST_SUITE_END();
|