luau/tests/Simplify.test.cpp
aaron b23d43496b
Sync to upstream/release/641 (#1382)
### What's new

* Light update this week, mostly fast flag cleanups.

### New Solver

* Rename flag to enable new solver from
`DebugLuauDeferredConstraintResolution` to `LuauSolverV2`
* Added support for magic functions for the new type checker (as opposed
to the type inference component)
* Improved handling of `string.format` with magic function improvements
* Cleaning up some of the reported errors by the new type checker
* Minor refactoring of `TypeChecker2.cpp` that happens to make the diff
very hard to read.

---

### Internal Contributors

Co-authored-by: Aaron Weiss <aaronweiss@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>

---------

Co-authored-by: Alexander McCord <amccord@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Vighnesh <vvijay@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Junseo Yoo <jyoo@roblox.com>
2024-08-30 13:16:51 -07:00

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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 "Fixture.h"
#include "doctest.h"
#include "Luau/Simplify.h"
using namespace Luau;
LUAU_FASTFLAG(LuauSolverV2)
LUAU_DYNAMIC_FASTINT(LuauSimplificationComplexityLimit)
namespace
{
struct SimplifyFixture : Fixture
{
TypeArena _arena;
const NotNull<TypeArena> arena{&_arena};
ToStringOptions opts;
Scope scope{builtinTypes->anyTypePack};
const TypeId anyTy = builtinTypes->anyType;
const TypeId unknownTy = builtinTypes->unknownType;
const TypeId neverTy = builtinTypes->neverType;
const TypeId errorTy = builtinTypes->errorType;
const TypeId functionTy = builtinTypes->functionType;
const TypeId tableTy = builtinTypes->tableType;
const TypeId numberTy = builtinTypes->numberType;
const TypeId stringTy = builtinTypes->stringType;
const TypeId booleanTy = builtinTypes->booleanType;
const TypeId nilTy = builtinTypes->nilType;
const TypeId classTy = builtinTypes->classType;
const TypeId trueTy = builtinTypes->trueType;
const TypeId falseTy = builtinTypes->falseType;
const TypeId truthyTy = builtinTypes->truthyType;
const TypeId falsyTy = builtinTypes->falsyType;
const TypeId freeTy = freshType(arena, builtinTypes, &scope);
const TypeId genericTy = arena->addType(GenericType{});
const TypeId blockedTy = arena->addType(BlockedType{});
const TypeId pendingTy = arena->addType(PendingExpansionType{{}, {}, {}, {}});
const TypeId helloTy = arena->addType(SingletonType{StringSingleton{"hello"}});
const TypeId worldTy = arena->addType(SingletonType{StringSingleton{"world"}});
const TypePackId emptyTypePack = arena->addTypePack({});
const TypeId fn1Ty = arena->addType(FunctionType{emptyTypePack, emptyTypePack});
const TypeId fn2Ty = arena->addType(FunctionType{builtinTypes->anyTypePack, emptyTypePack});
TypeId parentClassTy = nullptr;
TypeId childClassTy = nullptr;
TypeId anotherChildClassTy = nullptr;
TypeId unrelatedClassTy = nullptr;
ScopedFastFlag sff{FFlag::LuauSolverV2, true};
SimplifyFixture()
{
createSomeClasses(&frontend);
parentClassTy = frontend.globals.globalScope->linearSearchForBinding("Parent")->typeId;
childClassTy = frontend.globals.globalScope->linearSearchForBinding("Child")->typeId;
anotherChildClassTy = frontend.globals.globalScope->linearSearchForBinding("AnotherChild")->typeId;
unrelatedClassTy = frontend.globals.globalScope->linearSearchForBinding("Unrelated")->typeId;
}
TypeId intersect(TypeId a, TypeId b)
{
return simplifyIntersection(builtinTypes, arena, a, b).result;
}
std::string intersectStr(TypeId a, TypeId b)
{
return toString(intersect(a, b), opts);
}
bool isIntersection(TypeId a)
{
return bool(get<IntersectionType>(follow(a)));
}
TypeId mkTable(std::map<Name, TypeId> propTypes)
{
TableType::Props props;
for (const auto& [name, ty] : propTypes)
props[name] = Property{ty};
return arena->addType(TableType{props, {}, TypeLevel{}, TableState::Sealed});
}
TypeId mkNegation(TypeId ty)
{
return arena->addType(NegationType{ty});
}
TypeId mkFunction(TypeId arg, TypeId ret)
{
return arena->addType(FunctionType{arena->addTypePack({arg}), arena->addTypePack({ret})});
}
TypeId union_(TypeId a, TypeId b)
{
return simplifyUnion(builtinTypes, arena, a, b).result;
}
};
} // namespace
TEST_SUITE_BEGIN("Simplify");
TEST_CASE_FIXTURE(SimplifyFixture, "overload_negation_refinement_is_never")
{
TypeId f1 = mkFunction(stringTy, numberTy);
TypeId f2 = mkFunction(numberTy, stringTy);
TypeId intersection = arena->addType(IntersectionType{{f1, f2}});
TypeId unionT = arena->addType(UnionType{{errorTy, functionTy}});
TypeId negationT = mkNegation(unionT);
// The intersection of string -> number & number -> string, ~(error | function)
CHECK(neverTy == intersect(intersection, negationT));
}
TEST_CASE_FIXTURE(SimplifyFixture, "unknown_and_other_tops_and_bottom_types")
{
CHECK(unknownTy == intersect(unknownTy, unknownTy));
CHECK("any" == intersectStr(unknownTy, anyTy));
CHECK("any" == intersectStr(anyTy, unknownTy));
CHECK(neverTy == intersect(unknownTy, neverTy));
CHECK(neverTy == intersect(neverTy, unknownTy));
CHECK(errorTy == intersect(unknownTy, errorTy));
CHECK(errorTy == intersect(errorTy, unknownTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "nil")
{
CHECK(nilTy == intersect(nilTy, nilTy));
CHECK(neverTy == intersect(nilTy, numberTy));
CHECK(neverTy == intersect(nilTy, trueTy));
CHECK(neverTy == intersect(nilTy, tableTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "boolean_singletons")
{
CHECK(trueTy == intersect(trueTy, booleanTy));
CHECK(trueTy == intersect(booleanTy, trueTy));
CHECK(falseTy == intersect(falseTy, booleanTy));
CHECK(falseTy == intersect(booleanTy, falseTy));
CHECK(neverTy == intersect(falseTy, trueTy));
CHECK(neverTy == intersect(trueTy, falseTy));
CHECK(booleanTy == union_(trueTy, booleanTy));
CHECK(booleanTy == union_(booleanTy, trueTy));
CHECK(booleanTy == union_(falseTy, booleanTy));
CHECK(booleanTy == union_(booleanTy, falseTy));
CHECK(booleanTy == union_(falseTy, trueTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "boolean_and_truthy_and_falsy")
{
TypeId optionalBooleanTy = arena->addType(UnionType{{booleanTy, nilTy}});
CHECK(trueTy == intersect(booleanTy, truthyTy));
CHECK(trueTy == intersect(optionalBooleanTy, truthyTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "any_and_indeterminate_types")
{
CHECK("'a | *error-type*" == intersectStr(anyTy, freeTy));
CHECK("'a | *error-type*" == intersectStr(freeTy, anyTy));
CHECK("*error-type* | b" == intersectStr(anyTy, genericTy));
CHECK("*error-type* | b" == intersectStr(genericTy, anyTy));
auto anyRhsBlocked = get<UnionType>(intersect(anyTy, blockedTy));
auto anyLhsBlocked = get<UnionType>(intersect(blockedTy, anyTy));
REQUIRE(anyRhsBlocked);
REQUIRE(anyRhsBlocked->options.size() == 2);
CHECK(blockedTy == anyRhsBlocked->options[0]);
CHECK(errorTy == anyRhsBlocked->options[1]);
REQUIRE(anyLhsBlocked);
REQUIRE(anyLhsBlocked->options.size() == 2);
CHECK(blockedTy == anyLhsBlocked->options[0]);
CHECK(errorTy == anyLhsBlocked->options[1]);
auto anyRhsPending = get<UnionType>(intersect(anyTy, pendingTy));
auto anyLhsPending = get<UnionType>(intersect(pendingTy, anyTy));
REQUIRE(anyRhsPending);
REQUIRE(anyRhsPending->options.size() == 2);
CHECK(pendingTy == anyRhsPending->options[0]);
CHECK(errorTy == anyRhsPending->options[1]);
REQUIRE(anyLhsPending);
REQUIRE(anyLhsPending->options.size() == 2);
CHECK(pendingTy == anyLhsPending->options[0]);
CHECK(errorTy == anyLhsPending->options[1]);
}
TEST_CASE_FIXTURE(SimplifyFixture, "union_where_lhs_elements_are_a_subset_of_the_rhs")
{
TypeId lhs = union_(numberTy, stringTy);
TypeId rhs = union_(stringTy, numberTy);
CHECK("number | string" == toString(union_(lhs, rhs)));
}
TEST_CASE_FIXTURE(SimplifyFixture, "unknown_and_indeterminate_types")
{
CHECK(freeTy == intersect(unknownTy, freeTy));
CHECK(freeTy == intersect(freeTy, unknownTy));
CHECK(genericTy == intersect(unknownTy, genericTy));
CHECK(genericTy == intersect(genericTy, unknownTy));
CHECK(blockedTy == intersect(unknownTy, blockedTy));
CHECK(blockedTy == intersect(unknownTy, blockedTy));
CHECK(pendingTy == intersect(unknownTy, pendingTy));
CHECK(pendingTy == intersect(unknownTy, pendingTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "unknown_and_concrete")
{
CHECK(numberTy == intersect(numberTy, unknownTy));
CHECK(numberTy == intersect(unknownTy, numberTy));
CHECK(trueTy == intersect(trueTy, unknownTy));
CHECK(trueTy == intersect(unknownTy, trueTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "error_and_other_tops_and_bottom_types")
{
CHECK(errorTy == intersect(errorTy, errorTy));
CHECK(errorTy == intersect(errorTy, anyTy));
CHECK(errorTy == intersect(anyTy, errorTy));
CHECK(neverTy == intersect(errorTy, neverTy));
CHECK(neverTy == intersect(neverTy, errorTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "error_and_indeterminate_types")
{
CHECK("'a & *error-type*" == intersectStr(errorTy, freeTy));
CHECK("'a & *error-type*" == intersectStr(freeTy, errorTy));
CHECK("*error-type* & b" == intersectStr(errorTy, genericTy));
CHECK("*error-type* & b" == intersectStr(genericTy, errorTy));
CHECK(isIntersection(intersect(errorTy, blockedTy)));
CHECK(isIntersection(intersect(blockedTy, errorTy)));
CHECK(isIntersection(intersect(errorTy, pendingTy)));
CHECK(isIntersection(intersect(pendingTy, errorTy)));
}
TEST_CASE_FIXTURE(SimplifyFixture, "unknown_and_concrete")
{
CHECK(neverTy == intersect(numberTy, errorTy));
CHECK(neverTy == intersect(errorTy, numberTy));
CHECK(neverTy == intersect(trueTy, errorTy));
CHECK(neverTy == intersect(errorTy, trueTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "primitives")
{
// This shouldn't be possible, but we'll make it work even if it is.
TypeId numberTyDuplicate = arena->addType(PrimitiveType{PrimitiveType::Number});
CHECK(numberTy == intersect(numberTy, numberTyDuplicate));
CHECK(neverTy == intersect(numberTy, stringTy));
CHECK(neverTy == intersect(neverTy, numberTy));
CHECK(neverTy == intersect(numberTy, neverTy));
CHECK(neverTy == intersect(neverTy, functionTy));
CHECK(neverTy == intersect(functionTy, neverTy));
CHECK(neverTy == intersect(neverTy, tableTy));
CHECK(neverTy == intersect(tableTy, neverTy));
CHECK("*error-type* | number" == intersectStr(anyTy, numberTy));
CHECK("*error-type* | number" == intersectStr(numberTy, anyTy));
CHECK(neverTy == intersect(stringTy, nilTy));
CHECK(neverTy == intersect(nilTy, stringTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "primitives_and_falsy")
{
CHECK(neverTy == intersect(numberTy, falsyTy));
CHECK(neverTy == intersect(falsyTy, numberTy));
CHECK(nilTy == intersect(nilTy, falsyTy));
CHECK(nilTy == intersect(falsyTy, nilTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "primitives_and_singletons")
{
CHECK(helloTy == intersect(helloTy, stringTy));
CHECK(helloTy == intersect(stringTy, helloTy));
CHECK(neverTy == intersect(worldTy, helloTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "functions")
{
CHECK(fn1Ty == intersect(fn1Ty, functionTy));
CHECK(fn1Ty == intersect(functionTy, fn1Ty));
// Intersections of functions are super weird if you think about it.
CHECK("(() -> ()) & ((...any) -> ())" == intersectStr(fn1Ty, fn2Ty));
}
TEST_CASE_FIXTURE(SimplifyFixture, "negated_top_function_type")
{
TypeId negatedFunctionTy = mkNegation(functionTy);
CHECK(numberTy == intersect(numberTy, negatedFunctionTy));
CHECK(numberTy == intersect(negatedFunctionTy, numberTy));
CHECK(falsyTy == intersect(falsyTy, negatedFunctionTy));
CHECK(falsyTy == intersect(negatedFunctionTy, falsyTy));
TypeId f = mkFunction(stringTy, numberTy);
CHECK(neverTy == intersect(f, negatedFunctionTy));
CHECK(neverTy == intersect(negatedFunctionTy, f));
}
TEST_CASE_FIXTURE(SimplifyFixture, "optional_overloaded_function_and_top_function")
{
// (((number) -> string) & ((string) -> number))? & ~function
TypeId f1 = mkFunction(numberTy, stringTy);
TypeId f2 = mkFunction(stringTy, numberTy);
TypeId f12 = arena->addType(IntersectionType{{f1, f2}});
TypeId t = arena->addType(UnionType{{f12, nilTy}});
TypeId notFunctionTy = mkNegation(functionTy);
CHECK(nilTy == intersect(t, notFunctionTy));
CHECK(nilTy == intersect(notFunctionTy, t));
}
TEST_CASE_FIXTURE(SimplifyFixture, "negated_function_does_not_intersect_cleanly_with_truthy")
{
// ~function & ~(false?)
// ~function & ~(false | nil)
// ~function & ~false & ~nil
TypeId negatedFunctionTy = mkNegation(functionTy);
CHECK(isIntersection(intersect(negatedFunctionTy, truthyTy)));
}
TEST_CASE_FIXTURE(SimplifyFixture, "tables")
{
TypeId t1 = mkTable({{"tag", stringTy}});
CHECK(t1 == intersect(t1, tableTy));
CHECK(neverTy == intersect(t1, functionTy));
TypeId t2 = mkTable({{"tag", helloTy}});
CHECK(t2 == intersect(t1, t2));
CHECK(t2 == intersect(t2, t1));
TypeId t3 = mkTable({});
// {tag : string} intersect {}
CHECK(t1 == intersect(t1, t3));
CHECK(t1 == intersect(t3, t1));
}
TEST_CASE_FIXTURE(SimplifyFixture, "combine_disjoint_sealed_tables")
{
TypeId t1 = mkTable({{"prop", stringTy}});
TypeId t2 = mkTable({{"second_prop", numberTy}});
CHECK("{ prop: string, second_prop: number }" == toString(intersect(t1, t2)));
}
TEST_CASE_FIXTURE(SimplifyFixture, "non_disjoint_tables_do_not_simplify")
{
TypeId t1 = mkTable({{"prop", stringTy}});
TypeId t2 = mkTable({{"prop", unknownTy}, {"second_prop", numberTy}});
CHECK("{ prop: string } & { prop: unknown, second_prop: number }" == toString(intersect(t1, t2)));
}
// Simplification has an extra code path especially for intersections with
// single-property tables, so it's worthwhile to separately test the case where
// both tables have multiple properties.
TEST_CASE_FIXTURE(SimplifyFixture, "non_disjoint_tables_do_not_simplify_2")
{
TypeId t1 = mkTable({{"prop", stringTy}, {"third_prop", numberTy}});
TypeId t2 = mkTable({{"prop", unknownTy}, {"second_prop", numberTy}});
CHECK("{ prop: string, third_prop: number } & { prop: unknown, second_prop: number }" == toString(intersect(t1, t2)));
}
TEST_CASE_FIXTURE(SimplifyFixture, "tables_and_top_table")
{
TypeId notTableType = mkNegation(tableTy);
TypeId t1 = mkTable({{"prop", stringTy}, {"another", numberTy}});
CHECK(t1 == intersect(t1, tableTy));
CHECK(t1 == intersect(tableTy, t1));
CHECK(neverTy == intersect(t1, notTableType));
CHECK(neverTy == intersect(notTableType, t1));
}
TEST_CASE_FIXTURE(SimplifyFixture, "tables_and_truthy")
{
TypeId t1 = mkTable({{"prop", stringTy}, {"another", numberTy}});
CHECK(t1 == intersect(t1, truthyTy));
CHECK(t1 == intersect(truthyTy, t1));
}
TEST_CASE_FIXTURE(SimplifyFixture, "table_with_a_tag")
{
// {tag: string, prop: number} & {tag: "hello"}
// I think we can decline to simplify this:
TypeId t1 = mkTable({{"tag", stringTy}, {"prop", numberTy}});
TypeId t2 = mkTable({{"tag", helloTy}});
CHECK("{ prop: number, tag: string } & { tag: \"hello\" }" == intersectStr(t1, t2));
CHECK("{ prop: number, tag: string } & { tag: \"hello\" }" == intersectStr(t2, t1));
}
TEST_CASE_FIXTURE(SimplifyFixture, "nested_table_tag_test")
{
TypeId t1 = mkTable({
{"subtable",
mkTable({
{"tag", helloTy},
{"subprop", numberTy},
})},
{"prop", stringTy},
});
TypeId t2 = mkTable({
{"subtable",
mkTable({
{"tag", helloTy},
})},
});
CHECK(t1 == intersect(t1, t2));
CHECK(t1 == intersect(t2, t1));
}
TEST_CASE_FIXTURE(SimplifyFixture, "union")
{
TypeId t1 = arena->addType(UnionType{{numberTy, stringTy, nilTy, tableTy}});
CHECK(nilTy == intersect(t1, nilTy));
// CHECK(nilTy == intersect(nilTy, t1)); // TODO?
CHECK(builtinTypes->stringType == intersect(builtinTypes->optionalStringType, truthyTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "two_unions")
{
ScopedFastInt sfi{DFInt::LuauSimplificationComplexityLimit, 10};
TypeId t1 = arena->addType(UnionType{{numberTy, booleanTy, stringTy, nilTy, tableTy}});
CHECK("false?" == intersectStr(t1, falsyTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "curious_union")
{
// (a & false) | (a & nil)
TypeId curious =
arena->addType(UnionType{{arena->addType(IntersectionType{{freeTy, falseTy}}), arena->addType(IntersectionType{{freeTy, nilTy}})}});
CHECK("('a & false) | ('a & nil) | number" == toString(union_(curious, numberTy)));
}
TEST_CASE_FIXTURE(SimplifyFixture, "negations")
{
TypeId notNumberTy = mkNegation(numberTy);
TypeId notStringTy = mkNegation(stringTy);
CHECK(neverTy == intersect(numberTy, notNumberTy));
CHECK(numberTy == intersect(numberTy, notStringTy));
CHECK(numberTy == intersect(notStringTy, numberTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "top_class_type")
{
CHECK(neverTy == intersect(classTy, stringTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "classes")
{
CHECK(childClassTy == intersect(childClassTy, parentClassTy));
CHECK(childClassTy == intersect(parentClassTy, childClassTy));
CHECK(parentClassTy == union_(childClassTy, parentClassTy));
CHECK(parentClassTy == union_(parentClassTy, childClassTy));
CHECK(neverTy == intersect(childClassTy, unrelatedClassTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "negations_of_classes")
{
TypeId notChildClassTy = mkNegation(childClassTy);
TypeId notParentClassTy = mkNegation(parentClassTy);
CHECK(neverTy == intersect(childClassTy, notParentClassTy));
CHECK(neverTy == intersect(notParentClassTy, childClassTy));
CHECK("Parent & ~Child" == intersectStr(notChildClassTy, parentClassTy));
CHECK("Parent & ~Child" == intersectStr(parentClassTy, notChildClassTy));
CHECK(notParentClassTy == intersect(notChildClassTy, notParentClassTy));
CHECK(notParentClassTy == intersect(notParentClassTy, notChildClassTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "intersection_of_intersection_of_a_free_type_can_result_in_removal_of_that_free_type")
{
// a & string and number
// (a & number) & (string & number)
TypeId t1 = arena->addType(IntersectionType{{freeTy, stringTy}});
CHECK(neverTy == intersect(t1, numberTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "some_tables_are_really_never")
{
TypeId notAnyTy = mkNegation(anyTy);
TypeId t1 = mkTable({{"someKey", notAnyTy}});
CHECK(neverTy == intersect(t1, numberTy));
CHECK(neverTy == intersect(numberTy, t1));
CHECK(t1 == intersect(t1, t1));
TypeId notUnknownTy = mkNegation(unknownTy);
TypeId t2 = mkTable({{"someKey", notUnknownTy}});
CHECK(neverTy == intersect(t2, numberTy));
CHECK(neverTy == intersect(numberTy, t2));
CHECK(neverTy == intersect(t2, t2));
}
TEST_CASE_FIXTURE(SimplifyFixture, "simplify_stops_at_cycles")
{
TypeId t = mkTable({});
TableType* tt = getMutable<TableType>(t);
REQUIRE(tt);
TypeId t2 = mkTable({});
TableType* t2t = getMutable<TableType>(t2);
REQUIRE(t2t);
tt->props["cyclic"] = Property{t2};
t2t->props["cyclic"] = Property{t};
CHECK(t == intersect(t, unknownTy));
CHECK(t == intersect(unknownTy, t));
CHECK(t2 == intersect(t2, unknownTy));
CHECK(t2 == intersect(unknownTy, t2));
CHECK("*error-type* | t1 where t1 = { cyclic: { cyclic: t1 } }" == intersectStr(t, anyTy));
CHECK("*error-type* | t1 where t1 = { cyclic: { cyclic: t1 } }" == intersectStr(anyTy, t));
CHECK("*error-type* | t1 where t1 = { cyclic: { cyclic: t1 } }" == intersectStr(t2, anyTy));
CHECK("*error-type* | t1 where t1 = { cyclic: { cyclic: t1 } }" == intersectStr(anyTy, t2));
}
TEST_CASE_FIXTURE(SimplifyFixture, "free_type_bound_by_any_with_any")
{
CHECK("'a | *error-type*" == intersectStr(freeTy, anyTy));
CHECK("'a | *error-type*" == intersectStr(anyTy, freeTy));
CHECK("'a | *error-type*" == intersectStr(freeTy, anyTy));
CHECK("'a | *error-type*" == intersectStr(anyTy, freeTy));
}
TEST_CASE_FIXTURE(SimplifyFixture, "bound_intersected_by_itself_should_be_itself")
{
TypeId blocked = arena->addType(BlockedType{});
CHECK(toString(blocked) == intersectStr(blocked, blocked));
}
TEST_CASE_FIXTURE(SimplifyFixture, "cyclic_never_union_and_string")
{
// t1 where t1 = never | t1
TypeId leftType = arena->addType(UnionType{{builtinTypes->neverType, builtinTypes->neverType}});
UnionType* leftUnion = getMutable<UnionType>(leftType);
REQUIRE(leftUnion);
leftUnion->options[0] = leftType;
CHECK(builtinTypes->stringType == union_(leftType, builtinTypes->stringType));
}
TEST_SUITE_END();