Sync to upstream/release/521 (#443)

Analysis/src/BuiltinDefinitions.cpp

@@ -9,7 +9,6 @@
 #include <algorithm>
 
 LUAU_FASTFLAG(LuauAssertStripsFalsyTypes)
-LUAU_FASTFLAGVARIABLE(LuauTableCloneType, false)
 LUAU_FASTFLAGVARIABLE(LuauSetMetaTableArgsCheck, false)
 
 /** FIXME: Many of these type definitions are not quite completely accurate.
@@ -289,9 +288,7 @@ void registerBuiltinTypes(TypeChecker& typeChecker)
     {
         // tabTy is a generic table type which we can't express via declaration syntax yet
         ttv->props["freeze"] = makeProperty(makeFunction(arena, std::nullopt, {tabTy}, {tabTy}), "@luau/global/table.freeze");
-
+        ttv->props["clone"] = makeProperty(makeFunction(arena, std::nullopt, {tabTy}, {tabTy}), "@luau/global/table.clone");
-        if (FFlag::LuauTableCloneType)
-            ttv->props["clone"] = makeProperty(makeFunction(arena, std::nullopt, {tabTy}, {tabTy}), "@luau/global/table.clone");
 
         attachMagicFunction(ttv->props["pack"].type, magicFunctionPack);
     }

Analysis/src/TypeInfer.cpp

@@ -27,6 +27,7 @@ LUAU_FASTFLAGVARIABLE(LuauWeakEqConstraint, false) // Eventually removed as fals
 LUAU_FASTFLAGVARIABLE(DebugLuauFreezeDuringUnification, false)
 LUAU_FASTFLAGVARIABLE(LuauRecursiveTypeParameterRestriction, false)
 LUAU_FASTFLAGVARIABLE(LuauGenericFunctionsDontCacheTypeParams, false)
+LUAU_FASTFLAGVARIABLE(LuauInferStatFunction, false)
 LUAU_FASTFLAGVARIABLE(LuauSealExports, false)
 LUAU_FASTFLAGVARIABLE(LuauSelfCallAutocompleteFix, false)
 LUAU_FASTFLAGVARIABLE(LuauDiscriminableUnions2, false)
@@ -34,7 +35,7 @@ LUAU_FASTFLAGVARIABLE(LuauExpectedTypesOfProperties, false)
 LUAU_FASTFLAGVARIABLE(LuauErrorRecoveryType, false)
 LUAU_FASTFLAGVARIABLE(LuauOnlyMutateInstantiatedTables, false)
 LUAU_FASTFLAGVARIABLE(LuauPropertiesGetExpectedType, false)
-LUAU_FASTFLAGVARIABLE(LuauStatFunctionSimplify2, false)
+LUAU_FASTFLAGVARIABLE(LuauStatFunctionSimplify3, false)
 LUAU_FASTFLAGVARIABLE(LuauUnsealedTableLiteral, false)
 LUAU_FASTFLAG(LuauTypeMismatchModuleName)
 LUAU_FASTFLAGVARIABLE(LuauTwoPassAliasDefinitionFix, false)
@@ -463,7 +464,18 @@ void TypeChecker::checkBlock(const ScopePtr& scope, const AstStatBlock& block)
         }
         else if (auto fun = (*protoIter)->as<AstStatFunction>())
         {
-            auto pair = checkFunctionSignature(scope, subLevel, *fun->func, fun->name->location, std::nullopt);
+            std::optional<TypeId> expectedType;
+
+            if (FFlag::LuauInferStatFunction && !fun->func->self)
+            {
+                if (auto name = fun->name->as<AstExprIndexName>())
+                {
+                    TypeId exprTy = checkExpr(scope, *name->expr).type;
+                    expectedType = getIndexTypeFromType(scope, exprTy, name->index.value, name->indexLocation, false);
+                }
+            }
+
+            auto pair = checkFunctionSignature(scope, subLevel, *fun->func, fun->name->location, expectedType);
             auto [funTy, funScope] = pair;
 
             functionDecls[*protoIter] = pair;
@@ -1103,7 +1115,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
         scope->bindings[name->local] = {anyIfNonstrict(quantify(funScope, ty, name->local->location)), name->local->location};
         return;
     }
-    else if (auto name = function.name->as<AstExprIndexName>(); name && FFlag::LuauStatFunctionSimplify2)
+    else if (auto name = function.name->as<AstExprIndexName>(); name && FFlag::LuauStatFunctionSimplify3)
     {
         TypeId exprTy = checkExpr(scope, *name->expr).type;
         TableTypeVar* ttv = getMutableTableType(exprTy);
@@ -1116,7 +1128,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
         }
         else if (ttv->state == TableState::Sealed)
         {
-            if (!ttv->indexer || !isPrim(ttv->indexer->indexType, PrimitiveTypeVar::String))
+            if (!getIndexTypeFromType(scope, exprTy, name->index.value, name->indexLocation, false))
                 reportError(TypeError{function.location, CannotExtendTable{exprTy, CannotExtendTable::Property, name->index.value}});
         }
 
@@ -1141,7 +1153,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
         if (ttv && ttv->state != TableState::Sealed)
             ttv->props[name->index.value] = {follow(quantify(funScope, ty, name->indexLocation)), /* deprecated */ false, {}, name->indexLocation};
     }
-    else if (FFlag::LuauStatFunctionSimplify2)
+    else if (FFlag::LuauStatFunctionSimplify3)
     {
         LUAU_ASSERT(function.name->is<AstExprError>());
 
@@ -1151,7 +1163,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
     }
     else if (function.func->self)
     {
-        LUAU_ASSERT(!FFlag::LuauStatFunctionSimplify2);
+        LUAU_ASSERT(!FFlag::LuauStatFunctionSimplify3);
 
         AstExprIndexName* indexName = function.name->as<AstExprIndexName>();
         if (!indexName)
@@ -1190,7 +1202,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
     }
     else
     {
-        LUAU_ASSERT(!FFlag::LuauStatFunctionSimplify2);
+        LUAU_ASSERT(!FFlag::LuauStatFunctionSimplify3);
 
         TypeId leftType = checkLValueBinding(scope, *function.name);
 
@@ -2985,7 +2997,7 @@ TypeId TypeChecker::checkFunctionName(const ScopePtr& scope, AstExpr& funName, T
             return errorRecoveryType(scope);
         }
 
-        if (FFlag::LuauStatFunctionSimplify2)
+        if (FFlag::LuauStatFunctionSimplify3)
         {
             if (lhsType->persistent)
                 return errorRecoveryType(scope);

Ast/include/Luau/TimeTrace.h

@@ -130,8 +130,8 @@ ThreadContext& getThreadContext();
 
 struct Scope
 {
-    explicit Scope(ThreadContext& context, uint16_t token)
+    explicit Scope(uint16_t token)
-        : context(context)
+        : context(getThreadContext())
     {
         if (!FFlag::DebugLuauTimeTracing)
             return;
@@ -152,8 +152,8 @@ struct Scope
 
 struct OptionalTailScope
 {
-    explicit OptionalTailScope(ThreadContext& context, uint16_t token, uint32_t threshold)
+    explicit OptionalTailScope(uint16_t token, uint32_t threshold)
-        : context(context)
+        : context(getThreadContext())
         , token(token)
         , threshold(threshold)
     {
@@ -188,27 +188,27 @@ struct OptionalTailScope
     uint32_t pos;
 };
 
-LUAU_NOINLINE std::pair<uint16_t, Luau::TimeTrace::ThreadContext&> createScopeData(const char* name, const char* category);
+LUAU_NOINLINE uint16_t createScopeData(const char* name, const char* category);
 
 } // namespace TimeTrace
 } // namespace Luau
 
 // Regular scope
 #define LUAU_TIMETRACE_SCOPE(name, category) \
-    static auto lttScopeStatic = Luau::TimeTrace::createScopeData(name, category); \
+    static uint16_t lttScopeStatic = Luau::TimeTrace::createScopeData(name, category); \
-    Luau::TimeTrace::Scope lttScope(lttScopeStatic.second, lttScopeStatic.first)
+    Luau::TimeTrace::Scope lttScope(lttScopeStatic)
 
 // A scope without nested scopes that may be skipped if the time it took is less than the threshold
 #define LUAU_TIMETRACE_OPTIONAL_TAIL_SCOPE(name, category, microsec) \
-    static auto lttScopeStaticOptTail = Luau::TimeTrace::createScopeData(name, category); \
+    static uint16_t lttScopeStaticOptTail = Luau::TimeTrace::createScopeData(name, category); \
-    Luau::TimeTrace::OptionalTailScope lttScope(lttScopeStaticOptTail.second, lttScopeStaticOptTail.first, microsec)
+    Luau::TimeTrace::OptionalTailScope lttScope(lttScopeStaticOptTail, microsec)
 
 // Extra key/value data can be added to regular scopes
 #define LUAU_TIMETRACE_ARGUMENT(name, value) \
     do \
     { \
         if (FFlag::DebugLuauTimeTracing) \
-            lttScopeStatic.second.eventArgument(name, value); \
+            lttScope.context.eventArgument(name, value); \
     } while (false)
 
 #else

Ast/src/Lexer.cpp

@@ -6,6 +6,8 @@
 
 #include <limits.h>
 
+LUAU_FASTFLAGVARIABLE(LuauParseLocationIgnoreCommentSkip, false)
+
 namespace Luau
 {
 
@@ -352,6 +354,8 @@ const Lexeme& Lexer::next()
 
 const Lexeme& Lexer::next(bool skipComments)
 {
+    bool first = true;
+
     // in skipComments mode we reject valid comments
     do
     {
@@ -359,9 +363,11 @@ const Lexeme& Lexer::next(bool skipComments)
         while (isSpace(peekch()))
             consume();
 
-        prevLocation = lexeme.location;
+        if (!FFlag::LuauParseLocationIgnoreCommentSkip || first)
+            prevLocation = lexeme.location;
 
         lexeme = readNext();
+        first = false;
     } while (skipComments && (lexeme.type == Lexeme::Comment || lexeme.type == Lexeme::BlockComment));
 
     return lexeme;

Ast/src/TimeTrace.cpp

@@ -246,10 +246,9 @@ ThreadContext& getThreadContext()
     return context;
 }
 
-std::pair<uint16_t, Luau::TimeTrace::ThreadContext&> createScopeData(const char* name, const char* category)
+uint16_t createScopeData(const char* name, const char* category)
 {
-    uint16_t token = createToken(Luau::TimeTrace::getGlobalContext(), name, category);
+    return createToken(Luau::TimeTrace::getGlobalContext(), name, category);
-    return {token, Luau::TimeTrace::getThreadContext()};
 }
 } // namespace TimeTrace
 } // namespace Luau

Compiler/include/Luau/Bytecode.h

@@ -376,8 +376,7 @@ enum LuauOpcode
 enum LuauBytecodeTag
 {
     // Bytecode version
-    LBC_VERSION = 1,
+    LBC_VERSION = 2,
-    LBC_VERSION_FUTURE = 2, // TODO: This will be removed in favor of LBC_VERSION with LuauBytecodeV2Force
     // Types of constant table entries
     LBC_CONSTANT_NIL = 0,
     LBC_CONSTANT_BOOLEAN,

Compiler/src/BytecodeBuilder.cpp

@@ -508,7 +508,7 @@ uint32_t BytecodeBuilder::getDebugPC() const
 void BytecodeBuilder::finalize()
 {
     LUAU_ASSERT(bytecode.empty());
-    bytecode = char(LBC_VERSION_FUTURE);
+    bytecode = char(LBC_VERSION);
 
     writeStringTable(bytecode);
 

VM/src/laux.cpp

@@ -11,8 +11,6 @@
 
 #include <string.h>
 
-LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauMorePreciseLuaLTypeName, false)
-
 /* convert a stack index to positive */
 #define abs_index(L, i) ((i) > 0 || (i) <= LUA_REGISTRYINDEX ? (i) : lua_gettop(L) + (i) + 1)
 
@@ -337,15 +335,8 @@ const char* luaL_findtable(lua_State* L, int idx, const char* fname, int szhint)
 
 const char* luaL_typename(lua_State* L, int idx)
 {
-    if (DFFlag::LuauMorePreciseLuaLTypeName)
+    const TValue* obj = luaA_toobject(L, idx);
-    {
+    return luaT_objtypename(L, obj);
-        const TValue* obj = luaA_toobject(L, idx);
-        return luaT_objtypename(L, obj);
-    }
-    else
-    {
-        return lua_typename(L, lua_type(L, idx));
-    }
 }
 
 /*

VM/src/lbaselib.cpp

@@ -11,8 +11,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-LUAU_DYNAMIC_FASTFLAG(LuauMorePreciseLuaLTypeName)
-
 static void writestring(const char* s, size_t l)
 {
     fwrite(s, 1, l, stdout);
@@ -189,31 +187,16 @@ static int luaB_gcinfo(lua_State* L)
 static int luaB_type(lua_State* L)
 {
     luaL_checkany(L, 1);
-    if (DFFlag::LuauMorePreciseLuaLTypeName)
+    /* resulting name doesn't differentiate between userdata types */
-    {
+    lua_pushstring(L, lua_typename(L, lua_type(L, 1)));
-        /* resulting name doesn't differentiate between userdata types */
-        lua_pushstring(L, lua_typename(L, lua_type(L, 1)));
-    }
-    else
-    {
-        lua_pushstring(L, luaL_typename(L, 1));
-    }
     return 1;
 }
 
 static int luaB_typeof(lua_State* L)
 {
     luaL_checkany(L, 1);
-    if (DFFlag::LuauMorePreciseLuaLTypeName)
+    /* resulting name returns __type if specified unless the input is a newproxy-created userdata */
-    {
+    lua_pushstring(L, luaL_typename(L, 1));
-        /* resulting name returns __type if specified unless the input is a newproxy-created userdata */
-        lua_pushstring(L, luaL_typename(L, 1));
-    }
-    else
-    {
-        const TValue* obj = luaA_toobject(L, 1);
-        lua_pushstring(L, luaT_objtypename(L, obj));
-    }
     return 1;
 }
 

VM/src/ldebug.cpp

@@ -12,8 +12,6 @@
 #include <string.h>
 #include <stdio.h>
 
-LUAU_FASTFLAG(LuauBytecodeV2Force)
-
 static const char* getfuncname(Closure* f);
 
 static int currentpc(lua_State* L, CallInfo* ci)
@@ -91,16 +89,6 @@ const char* lua_setlocal(lua_State* L, int level, int n)
     return name;
 }
 
-static int getlinedefined(Proto* p)
-{
-    if (FFlag::LuauBytecodeV2Force)
-        return p->linedefined;
-    else if (p->linedefined >= 0)
-        return p->linedefined;
-    else
-        return luaG_getline(p, 0);
-}
-
 static int auxgetinfo(lua_State* L, const char* what, lua_Debug* ar, Closure* f, CallInfo* ci)
 {
     int status = 1;
@@ -120,7 +108,7 @@ static int auxgetinfo(lua_State* L, const char* what, lua_Debug* ar, Closure* f,
             {
                 ar->source = getstr(f->l.p->source);
                 ar->what = "Lua";
-                ar->linedefined = getlinedefined(f->l.p);
+                ar->linedefined = f->l.p->linedefined;
             }
             luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
             break;
@@ -133,7 +121,7 @@ static int auxgetinfo(lua_State* L, const char* what, lua_Debug* ar, Closure* f,
             }
             else
             {
-                ar->currentline = f->isC ? -1 : getlinedefined(f->l.p);
+                ar->currentline = f->isC ? -1 : f->l.p->linedefined;
             }
 
             break;
@@ -424,7 +412,7 @@ static void getcoverage(Proto* p, int depth, int* buffer, size_t size, void* con
     }
 
     const char* debugname = p->debugname ? getstr(p->debugname) : NULL;
-    int linedefined = getlinedefined(p);
+    int linedefined = p->linedefined;
 
     callback(context, debugname, linedefined, depth, buffer, size);
 

VM/src/lmem.h

@@ -10,12 +10,12 @@ union GCObject;
 #define luaM_newgco(L, t, size, memcat) cast_to(t*, luaM_newgco_(L, size, memcat))
 #define luaM_freegco(L, p, size, memcat, page) luaM_freegco_(L, obj2gco(p), size, memcat, page)
 
-#define luaM_arraysize_(n, e) ((cast_to(size_t, (n)) <= SIZE_MAX / (e)) ? (n) * (e) : (luaM_toobig(L), SIZE_MAX))
+#define luaM_arraysize_(L, n, e) ((cast_to(size_t, (n)) <= SIZE_MAX / (e)) ? (n) * (e) : (luaM_toobig(L), SIZE_MAX))
 
-#define luaM_newarray(L, n, t, memcat) cast_to(t*, luaM_new_(L, luaM_arraysize_(n, sizeof(t)), memcat))
+#define luaM_newarray(L, n, t, memcat) cast_to(t*, luaM_new_(L, luaM_arraysize_(L, n, sizeof(t)), memcat))
 #define luaM_freearray(L, b, n, t, memcat) luaM_free_(L, (b), (n) * sizeof(t), memcat)
 #define luaM_reallocarray(L, v, oldn, n, t, memcat) \
-    ((v) = cast_to(t*, luaM_realloc_(L, v, (oldn) * sizeof(t), luaM_arraysize_(n, sizeof(t)), memcat)))
+    ((v) = cast_to(t*, luaM_realloc_(L, v, (oldn) * sizeof(t), luaM_arraysize_(L, n, sizeof(t)), memcat)))
 
 LUAI_FUNC void* luaM_new_(lua_State* L, size_t nsize, uint8_t memcat);
 LUAI_FUNC GCObject* luaM_newgco_(lua_State* L, size_t nsize, uint8_t memcat);

VM/src/ltable.cpp

@@ -2,17 +2,26 @@
 // This code is based on Lua 5.x implementation licensed under MIT License; see lua_LICENSE.txt for details
 
 /*
-** Implementation of tables (aka arrays, objects, or hash tables).
+ * Implementation of tables (aka arrays, objects, or hash tables).
-** Tables keep its elements in two parts: an array part and a hash part.
+ *
-** Non-negative integer keys are all candidates to be kept in the array
+ * Tables keep the elements in two parts: an array part and a hash part.
-** part. The actual size of the array is the largest `n' such that at
+ * Integer keys >=1 are all candidates to be kept in the array part. The actual size of the array is the
-** least half the slots between 0 and n are in use.
+ * largest n such that at least half the slots between 0 and n are in use.
-** Hash uses a mix of chained scatter table with Brent's variation.
+ * Hash uses a mix of chained scatter table with Brent's variation.
-** A main invariant of these tables is that, if an element is not
+ *
-** in its main position (i.e. the `original' position that its hash gives
+ * A main invariant of these tables is that, if an element is not in its main position (i.e. the original
-** to it), then the colliding element is in its own main position.
+ * position that its hash gives to it), then the colliding element is in its own main position.
-** Hence even when the load factor reaches 100%, performance remains good.
+ * Hence even when the load factor reaches 100%, performance remains good.
-*/
+ *
+ * Table keys can be arbitrary values unless they contain NaN. Keys are hashed and compared using raw equality,
+ * so even if the key is a userdata with an overridden __eq, it's not used during hash lookups.
+ *
+ * Each table has a "boundary", defined as the index k where t[k] ~= nil and t[k+1] == nil. The boundary can be
+ * computed using a binary search and can be adjusted when the table is modified; crucially, Luau enforces an
+ * invariant where the boundary must be in the array part - this enforces a consistent iteration order through the
+ * prefix of the table when using pairs(), and allows to implement algorithms that access elements in 1..#t range
+ * more efficiently.
+ */
 
 #include "ltable.h"
 
@@ -25,6 +34,7 @@
 #include <string.h>
 
 LUAU_FASTFLAGVARIABLE(LuauTableRehashRework, false)
+LUAU_FASTFLAGVARIABLE(LuauTableNewBoundary, false)
 
 // max size of both array and hash part is 2^MAXBITS
 #define MAXBITS 26
@@ -460,7 +470,20 @@ static void rehash(lua_State* L, Table* t, const TValue* ek)
     totaluse++;
     /* compute new size for array part */
     int na = computesizes(nums, &nasize);
+    /* enforce the boundary invariant; for performance, only do hash lookups if we must */
+    if (FFlag::LuauTableNewBoundary)
+    {
+        bool tbound = t->node != dummynode || nasize < t->sizearray;
+        int ekindex = ttisnumber(ek) ? arrayindex(nvalue(ek)) : -1;
+        /* move the array size up until the boundary is guaranteed to be inside the array part */
+        while (nasize + 1 == ekindex || (tbound && !ttisnil(luaH_getnum(t, nasize + 1))))
+        {
+            nasize++;
+            na++;
+        }
+    }
     /* resize the table to new computed sizes */
+    LUAU_ASSERT(na <= totaluse);
     resize(L, t, nasize, totaluse - na);
 }
 
@@ -520,10 +543,18 @@ static LuaNode* getfreepos(Table* t)
 */
 static TValue* newkey(lua_State* L, Table* t, const TValue* key)
 {
+    /* enforce boundary invariant */
+    if (FFlag::LuauTableNewBoundary && ttisnumber(key) && nvalue(key) == t->sizearray + 1)
+    {
+        rehash(L, t, key); /* grow table */
+
+        // after rehash, numeric keys might be located in the new array part, but won't be found in the node part
+        return arrayornewkey(L, t, key);
+    }
+
     LuaNode* mp = mainposition(t, key);
     if (!ttisnil(gval(mp)) || mp == dummynode)
     {
-        LuaNode* othern;
         LuaNode* n = getfreepos(t); /* get a free place */
         if (n == NULL)
         {                      /* cannot find a free place? */
@@ -542,7 +573,7 @@ static TValue* newkey(lua_State* L, Table* t, const TValue* key)
         LUAU_ASSERT(n != dummynode);
         TValue mk;
         getnodekey(L, &mk, mp);
-        othern = mainposition(t, &mk);
+        LuaNode* othern = mainposition(t, &mk);
         if (othern != mp)
         { /* is colliding node out of its main position? */
             /* yes; move colliding node into free position */
@@ -704,6 +735,7 @@ TValue* luaH_setstr(lua_State* L, Table* t, TString* key)
 
 static LUAU_NOINLINE int unbound_search(Table* t, unsigned int j)
 {
+    LUAU_ASSERT(!FFlag::LuauTableNewBoundary);
     unsigned int i = j; /* i is zero or a present index */
     j++;
     /* find `i' and `j' such that i is present and j is not */
@@ -788,6 +820,12 @@ int luaH_getn(Table* t)
         maybesetaboundary(t, boundary);
         return boundary;
     }
+    else if (FFlag::LuauTableNewBoundary)
+    {
+        /* validate boundary invariant */
+        LUAU_ASSERT(t->node == dummynode || ttisnil(luaH_getnum(t, j + 1)));
+        return j;
+    }
     /* else must find a boundary in hash part */
     else if (t->node == dummynode) /* hash part is empty? */
         return j;                  /* that is easy... */

VM/src/ltablib.cpp

@@ -10,7 +10,9 @@
 #include "ldebug.h"
 #include "lvm.h"
 
-LUAU_FASTFLAGVARIABLE(LuauTableClone, false)
+LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauTableMoveTelemetry2, false)
+
+void (*lua_table_move_telemetry)(lua_State* L, int f, int e, int t, int nf, int nt);
 
 static int foreachi(lua_State* L)
 {
@@ -197,6 +199,29 @@ static int tmove(lua_State* L)
     int tt = !lua_isnoneornil(L, 5) ? 5 : 1; /* destination table */
     luaL_checktype(L, tt, LUA_TTABLE);
 
+    void (*telemetrycb)(lua_State* L, int f, int e, int t, int nf, int nt) = lua_table_move_telemetry;
+
+    if (DFFlag::LuauTableMoveTelemetry2 && telemetrycb)
+    {
+        int nf = lua_objlen(L, 1);
+        int nt = lua_objlen(L, tt);
+
+        bool report = false;
+
+        // source index range must be in bounds in source table unless the table is empty (permits 1..#t moves)
+        if (!(f == 1 || (f >= 1 && f <= nf)))
+            report = true;
+        if (!(e == nf || (e >= 1 && e <= nf)))
+            report = true;
+
+        // destination index must be in bounds in dest table or be exactly at the first empty element (permits concats)
+        if (!(t == nt + 1 || (t >= 1 && t <= nt)))
+            report = true;
+
+        if (report)
+            telemetrycb(L, f, e, t, nf, nt);
+    }
+
     if (e >= f)
     { /* otherwise, nothing to move */
         luaL_argcheck(L, f > 0 || e < INT_MAX + f, 3, "too many elements to move");
@@ -512,9 +537,6 @@ static int tisfrozen(lua_State* L)
 
 static int tclone(lua_State* L)
 {
-    if (!FFlag::LuauTableClone)
-        luaG_runerror(L, "table.clone is not available");
-
     luaL_checktype(L, 1, LUA_TTABLE);
     luaL_argcheck(L, !luaL_getmetafield(L, 1, "__metatable"), 1, "table has a protected metatable");
 

VM/src/lvmexecute.cpp

@@ -16,6 +16,8 @@
 
 #include <string.h>
 
+LUAU_FASTFLAG(LuauTableNewBoundary)
+
 // Disable c99-designator to avoid the warning in CGOTO dispatch table
 #ifdef __clang__
 #if __has_warning("-Wc99-designator")
@@ -2266,9 +2268,9 @@ static void luau_execute(lua_State* L)
                             VM_NEXT();
                         }
                     }
-                    else if (h->lsizenode == 0 && ttisnil(gval(h->node)))
+                    else if (FFlag::LuauTableNewBoundary || (h->lsizenode == 0 && ttisnil(gval(h->node))))
                     {
-                        // hash part is empty: fallthrough to exit
+                        // fallthrough to exit
                         VM_NEXT();
                     }
                     else

VM/src/lvmload.cpp

@@ -13,8 +13,6 @@
 
 #include <string.h>
 
-LUAU_FASTFLAGVARIABLE(LuauBytecodeV2Force, false)
-
 // TODO: RAII deallocation doesn't work for longjmp builds if a memory error happens
 template<typename T>
 struct TempBuffer
@@ -156,12 +154,11 @@ int luau_load(lua_State* L, const char* chunkname, const char* data, size_t size
         return 1;
     }
 
-    if (FFlag::LuauBytecodeV2Force ? (version != LBC_VERSION_FUTURE) : (version != LBC_VERSION && version != LBC_VERSION_FUTURE))
+    if (version != LBC_VERSION)
     {
         char chunkid[LUA_IDSIZE];
         luaO_chunkid(chunkid, chunkname, LUA_IDSIZE);
-        lua_pushfstring(L, "%s: bytecode version mismatch (expected %d, got %d)", chunkid,
+        lua_pushfstring(L, "%s: bytecode version mismatch (expected %d, got %d)", chunkid, LBC_VERSION, version);
-            FFlag::LuauBytecodeV2Force ? LBC_VERSION_FUTURE : LBC_VERSION, version);
         return 1;
     }
 
@@ -292,11 +289,7 @@ int luau_load(lua_State* L, const char* chunkname, const char* data, size_t size
             p->p[j] = protos[fid];
         }
 
-        if (FFlag::LuauBytecodeV2Force || version == LBC_VERSION_FUTURE)
+        p->linedefined = readVarInt(data, size, offset);
-            p->linedefined = readVarInt(data, size, offset);
-        else
-            p->linedefined = -1;
-
         p->debugname = readString(strings, data, size, offset);
 
         uint8_t lineinfo = read<uint8_t>(data, size, offset);

tests/Autocomplete.test.cpp

@@ -14,7 +14,6 @@
 
 LUAU_FASTFLAG(LuauTraceTypesInNonstrictMode2)
 LUAU_FASTFLAG(LuauSetMetatableDoesNotTimeTravel)
-LUAU_FASTFLAG(LuauTableCloneType)
 
 using namespace Luau;
 
@@ -262,7 +261,7 @@ TEST_CASE_FIXTURE(ACFixture, "get_member_completions")
 
     auto ac = autocomplete('1');
 
-    CHECK_EQ(FFlag::LuauTableCloneType ? 17 : 16, ac.entryMap.size());
+    CHECK_EQ(17, ac.entryMap.size());
     CHECK(ac.entryMap.count("find"));
     CHECK(ac.entryMap.count("pack"));
     CHECK(!ac.entryMap.count("math"));
@@ -2221,7 +2220,7 @@ TEST_CASE_FIXTURE(ACFixture, "autocompleteSource")
 
     auto ac = autocompleteSource(frontend, source, Position{1, 24}, nullCallback).result;
 
-    CHECK_EQ(FFlag::LuauTableCloneType ? 17 : 16, ac.entryMap.size());
+    CHECK_EQ(17, ac.entryMap.size());
     CHECK(ac.entryMap.count("find"));
     CHECK(ac.entryMap.count("pack"));
     CHECK(!ac.entryMap.count("math"));

tests/Conformance.test.cpp

@@ -241,8 +241,6 @@ TEST_CASE("Math")
 
 TEST_CASE("Table")
 {
-    ScopedFastFlag sff("LuauTableClone", true);
-
     runConformance("nextvar.lua");
 }
 
@@ -467,8 +465,6 @@ static void populateRTTI(lua_State* L, Luau::TypeId type)
 
 TEST_CASE("Types")
 {
-    ScopedFastFlag sff("LuauTableCloneType", true);
-
     runConformance("types.lua", [](lua_State* L) {
         Luau::NullModuleResolver moduleResolver;
         Luau::InternalErrorReporter iceHandler;

tests/Parser.test.cpp

@@ -1604,6 +1604,20 @@ TEST_CASE_FIXTURE(Fixture, "end_extent_of_functions_unions_and_intersections")
     CHECK_EQ((Position{3, 42}), block->body.data[2]->location.end);
 }
 
+TEST_CASE_FIXTURE(Fixture, "end_extent_doesnt_consume_comments")
+{
+    ScopedFastFlag luauParseLocationIgnoreCommentSkip{"LuauParseLocationIgnoreCommentSkip", true};
+
+    AstStatBlock* block = parse(R"(
+        type F = number
+        --comment
+        print('hello')
+    )");
+
+    REQUIRE_EQ(2, block->body.size);
+    CHECK_EQ((Position{1, 23}), block->body.data[0]->location.end);
+}
+
 TEST_CASE_FIXTURE(Fixture, "parse_error_loop_control")
 {
     matchParseError("break", "break statement must be inside a loop");

tests/TypeInfer.functions.test.cpp

@@ -1270,7 +1270,7 @@ caused by:
 
 TEST_CASE_FIXTURE(Fixture, "function_decl_quantify_right_type")
 {
-    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify2", true};
+    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify3", true};
 
     fileResolver.source["game/isAMagicMock"] = R"(
 --!nonstrict
@@ -1294,7 +1294,7 @@ end
 
 TEST_CASE_FIXTURE(Fixture, "function_decl_non_self_sealed_overwrite")
 {
-    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify2", true};
+    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify3", true};
 
     CheckResult result = check(R"(
 function string.len(): number
@@ -1302,7 +1302,40 @@ function string.len(): number
 end
     )");
 
-    LUAU_REQUIRE_ERRORS(result);
+    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();
+
+    result = check(R"(
+print(string.len('hello'))
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
+TEST_CASE_FIXTURE(Fixture, "function_decl_non_self_sealed_overwrite_2")
+{
+    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify3", true};
+    ScopedFastFlag inferStatFunction{"LuauInferStatFunction", true};
+
+    CheckResult result = check(R"(
+local t: { f: ((x: number) -> number)? } = {}
+
+function t.f(x)
+    print(x + 5)
+    return x .. "asd"
+end
+
+t.f = function(x)
+    print(x + 5)
+    return x .. "asd"
+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, "strict_mode_ok_with_missing_arguments")
@@ -1319,7 +1352,7 @@ TEST_CASE_FIXTURE(Fixture, "strict_mode_ok_with_missing_arguments")
 
 TEST_CASE_FIXTURE(Fixture, "function_statement_sealed_table_assignment_through_indexer")
 {
-    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify2", true};
+    ScopedFastFlag statFunctionSimplify{"LuauStatFunctionSimplify3", true};
 
     CheckResult result = check(R"(
 local t: {[string]: () -> number} = {}

tests/conformance/nextvar.lua

@@ -550,4 +550,35 @@ do
   assert(not pcall(table.clone, 42))
 end
 
+-- test boundary invariant maintenance during rehash
+do
+  local arr = table.create(5, 42)
+
+  arr[1] = nil
+  arr.a = 'a' -- trigger rehash
+
+  assert(#arr == 5) -- technically 0 is also valid, but it happens to be 5 because array capacity is 5
+end
+
+-- test boundary invariant maintenance when replacing hash keys
+do
+  local arr = {}
+  arr.a = 'a'
+  arr.a = nil
+  arr[1] = 1 -- should rehash and resize array part, otherwise # won't find the boundary in array part
+
+  assert(#arr == 1)
+end
+
+-- test boundary invariant maintenance when table is filled from the end
+do
+  local arr = {}
+  for i=5,2,-1 do
+    arr[i] = i
+    assert(#arr == 0)
+  end
+  arr[1] = 1
+  assert(#arr == 5)
+end
+
 return"OK"