From 5e4f61f889bc46ceb6bceb5bd38715f5e4538914 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Mon, 5 Jan 2026 15:38:48 +0200
Subject: [PATCH 01/18] All opcodes have id

---
 crates/compiler-core/src/bytecode.rs | 457 ++++++++-------------------
 1 file changed, 124 insertions(+), 333 deletions(-)

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index dc61e3b9b5a..5bb9434492c 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -676,436 +676,227 @@ pub type NameIdx = u32;
 #[repr(u8)]
 pub enum Instruction {
     // ==================== No-argument instructions (opcode < 44) ====================
-    // 0: CACHE - placeholder for inline cache (not executed)
-    Cache,
-    // 1: BEFORE_ASYNC_WITH
-    BeforeAsyncWith,
-    // 2: BEFORE_WITH
-    BeforeWith,
-    // 3: Reserved (BINARY_OP_INPLACE_ADD_UNICODE in CPython)
-    Reserved3,
-    // 4: BINARY_SLICE - not implemented, placeholder
-    BinarySlice,
-    // 5: BINARY_SUBSCR
-    BinarySubscript,
-    // 6: CHECK_EG_MATCH
-    CheckEgMatch,
-    // 7: CHECK_EXC_MATCH
-    CheckExcMatch,
-    // 8: CLEANUP_THROW
-    CleanupThrow,
-    // 9: DELETE_SUBSCR
-    DeleteSubscript,
-    // 10: END_ASYNC_FOR
-    EndAsyncFor,
-    // 11: END_FOR - not implemented, placeholder
-    EndFor,
-    // 12: END_SEND
-    EndSend,
-    // 13: EXIT_INIT_CHECK - not implemented, placeholder
-    ExitInitCheck,
-    // 14: FORMAT_SIMPLE
-    FormatSimple,
-    // 15: FORMAT_WITH_SPEC
-    FormatWithSpec,
-    // 16: GET_AITER
-    GetAIter,
-    // 17: RESERVED
-    Reserved17,
-    // 18: GET_ANEXT
-    GetANext,
-    // 19: GET_ITER
-    GetIter,
-    // 20: GET_LEN
-    GetLen,
-    // 21: GET_YIELD_FROM_ITER - not implemented, placeholder
-    GetYieldFromIter,
-    // 22: INTERPRETER_EXIT - not implemented, placeholder
-    InterpreterExit,
-    // 23: LOAD_ASSERTION_ERROR - not implemented, placeholder
-    LoadAssertionError,
-    // 24: LOAD_BUILD_CLASS
-    LoadBuildClass,
-    // 25: LOAD_LOCALS - not implemented, placeholder
-    LoadLocals,
-    // 26: MAKE_FUNCTION
-    MakeFunction,
-    // 27: MATCH_KEYS
-    MatchKeys,
-    // 28: MATCH_MAPPING
-    MatchMapping,
-    // 29: MATCH_SEQUENCE
-    MatchSequence,
-    // 30: NOP
-    Nop,
-    // 31: POP_EXCEPT
-    PopException,
-    // 32: POP_TOP
-    PopTop,
-    // 33: PUSH_EXC_INFO
-    PushExcInfo,
-    // 34: PUSH_NULL - not implemented, placeholder
-    PushNull,
-    // 35: RETURN_GENERATOR - not implemented, placeholder
-    ReturnGenerator,
-    // 36: RETURN_VALUE
-    ReturnValue,
-    // 37: SETUP_ANNOTATIONS
-    SetupAnnotation,
-    // 38: STORE_SLICE - not implemented, placeholder
-    StoreSlice,
-    // 39: STORE_SUBSCR
-    StoreSubscript,
-    // 40: TO_BOOL
-    ToBool,
-    // 41: UNARY_INVERT
-    UnaryInvert,
-    // 42: UNARY_NEGATIVE
-    UnaryNegative,
-    // 43: UNARY_NOT
-    UnaryNot,
-    // ==================== With-argument instructions (opcode >= 44) ====================
-    // 44: WITH_EXCEPT_START
-    WithExceptStart,
-    // 45: BINARY_OP
+    BeforeAsyncWith = 1,
+    BeforeWith = 2,
+    BinarySubscr = 5,
+    CheckEgMatch = 6,
+    CheckExcMatch = 7,
+    CleanupThrow = 8,
+    DeleteSubscr = 9,
+    EndAsyncFor = 10,
+    EndSend = 12,
+    FormatSimple = 14,
+    FormatWithSpec = 15,
+    GetAIter = 16,
+    Reserved = 17,
+    GetANext = 18,
+    GetIter = 19,
+    GetLen = 20,
+    LoadBuildClass = 24,
+    MakeFunction = 26,
+    MatchKeys = 27,
+    MatchMapping = 28,
+    MatchSequence = 29,
+    Nop = 30,
+    PopExcept = 31,
+    PopTop = 32,
+    PushExcInfo = 33,
+    ReturnValue = 36,
+    SetupAnnotations = 37,
+    StoreSubscr = 39,
+    ToBool = 40,
+    WithExceptStart = 44,
+    // ==================== With-argument instructions (opcode > 44) ====================
     BinaryOp {
         op: Arg<BinaryOperator>,
-    },
-    // 46: BUILD_CONST_KEY_MAP - not implemented, placeholder
-    BuildConstKeyMap {
-        size: Arg<u32>,
-    },
-    // 47: BUILD_LIST
+    } = 45,
     BuildList {
         size: Arg<u32>,
-    },
-    // 48: BUILD_MAP
+    } = 47,
     BuildMap {
         size: Arg<u32>,
-    },
-    // 49: BUILD_SET
+    } = 48,
     BuildSet {
         size: Arg<u32>,
-    },
-    // 50: BUILD_SLICE
+    } = 49,
     BuildSlice {
         argc: Arg<BuildSliceArgCount>,
-    },
-    // 51: BUILD_STRING
+    } = 50,
     BuildString {
         size: Arg<u32>,
-    },
-    // 52: BUILD_TUPLE
+    } = 51,
     BuildTuple {
         size: Arg<u32>,
-    },
-    // 53: CALL
-    CallFunctionPositional {
+    } = 52,
+    Call {
         nargs: Arg<u32>,
-    },
-    // 54: CALL_FUNCTION_EX
+    } = 53,
     CallFunctionEx {
         has_kwargs: Arg<bool>,
-    },
-    // 55: CALL_INTRINSIC_1
+    } = 54,
     CallIntrinsic1 {
         func: Arg<IntrinsicFunction1>,
-    },
-    // 56: CALL_INTRINSIC_2
+    } = 55,
     CallIntrinsic2 {
         func: Arg<IntrinsicFunction2>,
-    },
-    // 57: CALL_KW
-    CallFunctionKeyword {
+    } = 56,
+    CallKw {
         nargs: Arg<u32>,
-    },
-    // 58: COMPARE_OP
-    CompareOperation {
+    } = 57,
+    CompareOp {
         op: Arg<ComparisonOperator>,
-    },
-    // 59: CONTAINS_OP
-    ContainsOp(Arg<Invert>),
-    // 60: CONVERT_VALUE
+    } = 58,
+    ContainsOp(Arg<Invert>) = 59,
     ConvertValue {
         oparg: Arg<ConvertValueOparg>,
-    },
-    // 61: COPY
+    } = 60,
     CopyItem {
         index: Arg<u32>,
-    },
-    // 62: COPY_FREE_VARS - not implemented, placeholder
-    CopyFreeVars {
-        count: Arg<u32>,
-    },
-    // 63: DELETE_ATTR
+    } = 61,
     DeleteAttr {
         idx: Arg<NameIdx>,
-    },
-    // 64: DELETE_DEREF
-    DeleteDeref(Arg<NameIdx>),
-    // 65: DELETE_FAST
-    DeleteFast(Arg<NameIdx>),
-    // 66: DELETE_GLOBAL
-    DeleteGlobal(Arg<NameIdx>),
-    // 67: DELETE_NAME
-    DeleteLocal(Arg<NameIdx>),
-    // 68: DICT_MERGE - not implemented, placeholder
-    DictMerge {
-        index: Arg<u32>,
-    },
-    // 69: DICT_UPDATE
+    } = 63,
+    DeleteDeref(Arg<NameIdx>) = 64,
+    DeleteFast(Arg<NameIdx>) = 65,
+    DeleteGlobal(Arg<NameIdx>) = 66,
+    DeleteName(Arg<NameIdx>) = 67,
     DictUpdate {
         index: Arg<u32>,
-    },
-    // 70: ENTER_EXECUTOR - not implemented, placeholder
-    EnterExecutor {
-        index: Arg<u32>,
-    },
-    // 71: EXTENDED_ARG
-    ExtendedArg,
-    // 72: FOR_ITER
+    } = 69,
+    ExtendedArg = 71,
     ForIter {
         target: Arg<Label>,
-    },
-    // 73: GET_AWAITABLE
-    GetAwaitable,
-    // 74: IMPORT_FROM
+    } = 72,
+    GetAwaitable = 73, // TODO: Make this instruction to hold an oparg
     ImportFrom {
         idx: Arg<NameIdx>,
-    },
-    // 75: IMPORT_NAME
+    } = 74,
     ImportName {
         idx: Arg<NameIdx>,
-    },
-    // 76: IS_OP
-    IsOp(Arg<Invert>),
-    // 77: JUMP_BACKWARD - not implemented, placeholder
-    JumpBackward {
-        target: Arg<Label>,
-    },
-    // 78: JUMP_BACKWARD_NO_INTERRUPT - not implemented, placeholder
-    JumpBackwardNoInterrupt {
-        target: Arg<Label>,
-    },
-    // 79: JUMP_FORWARD - not implemented, placeholder
-    JumpForward {
-        target: Arg<Label>,
-    },
-    // 80: LIST_APPEND
+    } = 75,
+    IsOp(Arg<Invert>) = 76,
     ListAppend {
         i: Arg<u32>,
-    },
-    // 81: LIST_EXTEND - not implemented, placeholder
-    ListExtend {
-        i: Arg<u32>,
-    },
-    // 82: LOAD_ATTR
+    } = 80,
     LoadAttr {
         idx: Arg<NameIdx>,
-    },
-    // 83: LOAD_CONST
+    } = 82,
     LoadConst {
         idx: Arg<u32>,
-    },
-    // 84: LOAD_DEREF
-    LoadDeref(Arg<NameIdx>),
-    // 85: LOAD_FAST
-    LoadFast(Arg<NameIdx>),
-    // 86: LOAD_FAST_AND_CLEAR
-    LoadFastAndClear(Arg<NameIdx>),
-    // 87: LOAD_FAST_CHECK - not implemented, placeholder
-    LoadFastCheck(Arg<NameIdx>),
-    // 88: LOAD_FAST_LOAD_FAST - not implemented, placeholder
-    LoadFastLoadFast {
-        arg: Arg<u32>,
-    },
-    // 89: LOAD_FROM_DICT_OR_DEREF - not implemented, placeholder
-    LoadFromDictOrDeref(Arg<NameIdx>),
-    // 90: LOAD_FROM_DICT_OR_GLOBALS - not implemented, placeholder
-    LoadFromDictOrGlobals(Arg<NameIdx>),
-    // 91: LOAD_GLOBAL
-    LoadGlobal(Arg<NameIdx>),
-    // 92: LOAD_NAME
-    LoadNameAny(Arg<NameIdx>),
-    // 93: LOAD_SUPER_ATTR - not implemented, placeholder
-    LoadSuperAttr {
-        arg: Arg<u32>,
-    },
-    // 94: MAKE_CELL - not implemented, placeholder
-    MakeCell(Arg<NameIdx>),
-    // 95: MAP_ADD
+    } = 83,
+    LoadDeref(Arg<NameIdx>) = 84,
+    LoadFast(Arg<NameIdx>) = 85,
+    LoadFastAndClear(Arg<NameIdx>) = 86,
+    LoadGlobal(Arg<NameIdx>) = 91,
+    LoadName(Arg<NameIdx>) = 92,
     MapAdd {
         i: Arg<u32>,
-    },
-    // 96: MATCH_CLASS
-    MatchClass(Arg<u32>),
-    // 97: POP_JUMP_IF_FALSE
+    } = 95,
+    MatchClass(Arg<u32>) = 96,
     PopJumpIfFalse {
         target: Arg<Label>,
-    },
-    // 98: POP_JUMP_IF_NONE - not implemented, placeholder
-    PopJumpIfNone {
-        target: Arg<Label>,
-    },
-    // 99: POP_JUMP_IF_NOT_NONE - not implemented, placeholder
-    PopJumpIfNotNone {
-        target: Arg<Label>,
-    },
-    // 100: POP_JUMP_IF_TRUE
+    } = 97,
     PopJumpIfTrue {
         target: Arg<Label>,
-    },
-    // 101: RAISE_VARARGS
-    Raise {
+    } = 100,
+    RaiseVarArgs {
         kind: Arg<RaiseKind>,
-    },
-    // 102: RERAISE
+    } = 101,
     Reraise {
         depth: Arg<u32>,
-    },
-    // 103: RETURN_CONST
+    } = 102,
     ReturnConst {
         idx: Arg<u32>,
-    },
-    // 104: SEND
+    } = 103,
     Send {
         target: Arg<Label>,
-    },
-    // 105: SET_ADD
+    } = 104,
     SetAdd {
         i: Arg<u32>,
-    },
-    // 106: SET_FUNCTION_ATTRIBUTE
+    } = 105,
     SetFunctionAttribute {
         attr: Arg<MakeFunctionFlags>,
-    },
-    // 107: SET_UPDATE - not implemented, placeholder
-    SetUpdate {
-        i: Arg<u32>,
-    },
-    // 108: STORE_ATTR
+    } = 106,
     StoreAttr {
         idx: Arg<NameIdx>,
-    },
-    // 109: STORE_DEREF
-    StoreDeref(Arg<NameIdx>),
-    // 110: STORE_FAST
-    StoreFast(Arg<NameIdx>),
-    // 111: STORE_FAST_LOAD_FAST
+    } = 108,
+    StoreDeref(Arg<NameIdx>) = 109,
+    StoreFast(Arg<NameIdx>) = 110,
     StoreFastLoadFast {
         store_idx: Arg<NameIdx>,
         load_idx: Arg<NameIdx>,
-    },
-    // 112: STORE_FAST_STORE_FAST - not implemented, placeholder
-    StoreFastStoreFast {
-        arg: Arg<u32>,
-    },
-    // 113: STORE_GLOBAL
-    StoreGlobal(Arg<NameIdx>),
-    // 114: STORE_NAME
-    StoreLocal(Arg<NameIdx>),
-    // 115: SWAP
+    } = 111,
+    StoreGlobal(Arg<NameIdx>) = 113,
+    StoreName(Arg<NameIdx>) = 114,
     Swap {
         index: Arg<u32>,
-    },
-    // 116: UNPACK_EX
+    } = 115,
     UnpackEx {
         args: Arg<UnpackExArgs>,
-    },
-    // 117: UNPACK_SEQUENCE
+    } = 116,
     UnpackSequence {
         size: Arg<u32>,
-    },
-    // 118: YIELD_VALUE
+    } = 117,
     YieldValue {
         arg: Arg<u32>,
-    },
-    // ==================== RustPython-only instructions (119+) ====================
-    // 119: BREAK
+    } = 118,
+    Resume {
+        arg: Arg<u32>,
+    } = 149,
+    // ==================== RustPython-only instructions (119-135) ====================
+    // Ideally, we want to be fully aligned with CPython opcodes, but we still have some leftovers.
+    // So we assign random IDs to these opcodes.
     Break {
         target: Arg<Label>,
-    },
-    // 120: BUILD_LIST_FROM_TUPLES
+    } = 119,
     BuildListFromTuples {
         size: Arg<u32>,
-    },
-    // 121: BUILD_MAP_FOR_CALL
+    } = 120,
     BuildMapForCall {
         size: Arg<u32>,
-    },
-    // 122: BUILD_SET_FROM_TUPLES
+    } = 121,
     BuildSetFromTuples {
         size: Arg<u32>,
-    },
-    // 123: BUILD_TUPLE_FROM_ITER
-    BuildTupleFromIter,
-    // 124: BUILD_TUPLE_FROM_TUPLES
+    } = 122,
+    BuildTupleFromIter = 123,
     BuildTupleFromTuples {
         size: Arg<u32>,
-    },
-    // 125: CALL_METHOD
+    } = 124,
     CallMethodPositional {
         nargs: Arg<u32>,
-    },
-    // 126: CALL_METHOD_KW
+    } = 125,
     CallMethodKeyword {
         nargs: Arg<u32>,
-    },
-    // 127: CALL_METHOD_EX
+    } = 126,
     CallMethodEx {
         has_kwargs: Arg<bool>,
-    },
-    // 128: CONTINUE
+    } = 127,
     Continue {
         target: Arg<Label>,
-    },
-    // 129: JUMP (CPython uses pseudo-op 256)
-    Jump {
-        target: Arg<Label>,
-    },
-    // 130: JUMP_IF_FALSE_OR_POP
+    } = 128,
     JumpIfFalseOrPop {
         target: Arg<Label>,
-    },
-    // 131: JUMP_IF_TRUE_OR_POP
+    } = 129,
     JumpIfTrueOrPop {
         target: Arg<Label>,
-    },
-    // 132: JUMP_IF_NOT_EXC_MATCH
-    JumpIfNotExcMatch(Arg<Label>),
-    // 133: LOAD_CLASSDEREF
-    LoadClassDeref(Arg<NameIdx>),
-    // 134: LOAD_CLOSURE (CPython uses pseudo-op 258)
-    LoadClosure(Arg<NameIdx>),
-    // 135: LOAD_METHOD (CPython uses pseudo-op 259)
-    LoadMethod {
-        idx: Arg<NameIdx>,
-    },
-    // 136: POP_BLOCK (CPython uses pseudo-op 263)
-    PopBlock,
-    // 137: REVERSE
+    } = 130,
+    JumpIfNotExcMatch(Arg<Label>) = 131,
+    LoadClassDeref(Arg<NameIdx>) = 132,
     Reverse {
         amount: Arg<u32>,
-    },
-    // 138: SET_EXC_INFO
-    SetExcInfo,
-    // 139: SUBSCRIPT
-    Subscript,
-    // 140-148: Reserved (padding to keep RESUME at 149)
-    Reserved140,
-    Reserved141,
-    Reserved142,
-    Reserved143,
-    Reserved144,
-    Reserved145,
-    Reserved146,
-    Reserved147,
-    Reserved148,
-    // 149: RESUME
-    Resume {
-        arg: Arg<u32>,
-    },
-    // If you add a new instruction here, be sure to keep LAST_INSTRUCTION updated
+    } = 133,
+    SetExcInfo = 134,
+    Subscript = 135,
+
+    // ===== Pseudo Opcodes (252+) ======
+    Jump {
+        target: Arg<Label>,
+    } = 252, // CPython uses pseudo-op 256
+    LoadClosure(Arg<NameIdx>) = 253, // CPython uses pseudo-op 258
+    LoadMethod {
+        idx: Arg<NameIdx>,
+    } = 254, // CPython uses pseudo-op 259
+    PopBlock = 255,                  // CPython uses pseudo-op 263
 }
 
 // This must be kept up to date to avoid marshaling errors

From 2b6b0bd2fc3d0c33891b6de5cfca83c323cb1c99 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 14:53:26 +0200
Subject: [PATCH 02/18] Fix names

---
 crates/compiler-core/src/bytecode.rs | 126 ++++++++-------------------
 1 file changed, 34 insertions(+), 92 deletions(-)

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index 5bb9434492c..db12ac2bbc2 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -705,6 +705,9 @@ pub enum Instruction {
     SetupAnnotations = 37,
     StoreSubscr = 39,
     ToBool = 40,
+    UnaryInvert = 41,
+    UnaryNegative = 42,
+    UnaryNot = 43,
     WithExceptStart = 44,
     // ==================== With-argument instructions (opcode > 44) ====================
     BinaryOp {
@@ -1648,13 +1651,7 @@ impl Instruction {
             | ForIter { target: l }
             | Break { target: l }
             | Continue { target: l }
-            | Send { target: l }
-            // Dummy jump instructions (placeholders)
-            | JumpBackward { target: l }
-            | JumpBackwardNoInterrupt { target: l }
-            | JumpForward { target: l }
-            | PopJumpIfNone { target: l }
-            | PopJumpIfNotNone { target: l } => Some(*l),
+            | Send { target: l } => Some(*l),
             _ => None,
         }
     }
@@ -1676,7 +1673,7 @@ impl Instruction {
                 | Break { .. }
                 | ReturnValue
                 | ReturnConst { .. }
-                | Raise { .. }
+                | RaiseVarArgs { .. }
                 | Reraise { .. }
         )
     }
@@ -1694,47 +1691,25 @@ impl Instruction {
     ///
     pub fn stack_effect(&self, arg: OpArg, jump: bool) -> i32 {
         match self {
-            // Dummy/placeholder instructions (never executed)
-            Cache | Reserved3 | Reserved17 | Reserved140 | Reserved141 | Reserved142
-            | Reserved143 | Reserved144 | Reserved145 | Reserved146 | Reserved147 | Reserved148 => {
-                0
-            }
-            BinarySlice | EndFor | ExitInitCheck | GetYieldFromIter | InterpreterExit
-            | LoadAssertionError | LoadLocals | PushNull | ReturnGenerator | StoreSlice => 0,
-            BuildConstKeyMap { .. }
-            | CopyFreeVars { .. }
-            | DictMerge { .. }
-            | EnterExecutor { .. }
-            | ListExtend { .. }
-            | LoadFastCheck(_)
-            | LoadFastLoadFast { .. }
-            | LoadFromDictOrDeref(_)
-            | LoadFromDictOrGlobals(_)
-            | LoadSuperAttr { .. }
-            | MakeCell(_)
-            | SetUpdate { .. }
-            | StoreFastStoreFast { .. } => 0,
-            JumpBackward { .. } | JumpBackwardNoInterrupt { .. } | JumpForward { .. } => 0,
-            PopJumpIfNone { .. } | PopJumpIfNotNone { .. } => -1,
-
             Nop => 0,
             ImportName { .. } => -1,
             ImportFrom { .. } => 1,
-            LoadFast(_) | LoadFastAndClear(_) | LoadNameAny(_) | LoadGlobal(_) | LoadDeref(_)
+            LoadFast(_) | LoadFastAndClear(_) | LoadName(_) | LoadGlobal(_) | LoadDeref(_)
             | LoadClassDeref(_) => 1,
-            StoreFast(_) | StoreLocal(_) | StoreGlobal(_) | StoreDeref(_) => -1,
+            StoreFast(_) | StoreName(_) | StoreGlobal(_) | StoreDeref(_) => -1,
             StoreFastLoadFast { .. } => 0, // pop 1, push 1
-            DeleteFast(_) | DeleteLocal(_) | DeleteGlobal(_) | DeleteDeref(_) => 0,
+            DeleteFast(_) | DeleteName(_) | DeleteGlobal(_) | DeleteDeref(_) => 0,
             LoadClosure(_) => 1,
             Subscript => -1,
-            StoreSubscript => -3,
-            DeleteSubscript => -2,
+            StoreSubscr => -3,
+            DeleteSubscr => -2,
             LoadAttr { .. } => 0,
             StoreAttr { .. } => -2,
             DeleteAttr { .. } => -1,
             LoadConst { .. } => 1,
-            BinaryOp { .. } | CompareOperation { .. } => -1,
-            BinarySubscript => -1,
+            Reserved => 0,
+            BinaryOp { .. } | CompareOp { .. } => -1,
+            BinarySubscr => -1,
             CopyItem { .. } => 1,
             PopTop => -1,
             Swap { .. } => 0,
@@ -1762,9 +1737,9 @@ impl Instruction {
                 // pops attribute value and function, pushes function back
                 -2 + 1
             }
-            CallFunctionPositional { nargs } => -(nargs.get(arg) as i32) - 1 + 1,
+            Call { nargs } => -(nargs.get(arg) as i32) - 1 + 1,
             CallMethodPositional { nargs } => -(nargs.get(arg) as i32) - 3 + 1,
-            CallFunctionKeyword { nargs } => -1 - (nargs.get(arg) as i32) - 1 + 1,
+            CallKw { nargs } => -1 - (nargs.get(arg) as i32) - 1 + 1,
             CallMethodKeyword { nargs } => -1 - (nargs.get(arg) as i32) - 3 + 1,
             CallFunctionEx { has_kwargs } => -1 - (has_kwargs.get(arg) as i32) - 1 + 1,
             CallMethodEx { has_kwargs } => -1 - (has_kwargs.get(arg) as i32) - 3 + 1,
@@ -1796,11 +1771,11 @@ impl Instruction {
             PushExcInfo => 1,    // [exc] -> [prev_exc, exc]
             CheckExcMatch => 0,  // [exc, type] -> [exc, bool] (pops type, pushes bool)
             Reraise { .. } => 0, // Exception raised, stack effect doesn't matter
-            SetupAnnotation => 0,
+            SetupAnnotations => 0,
             BeforeWith => 1, // push __exit__, then replace ctx_mgr with __enter__ result
             WithExceptStart => 1, // push __exit__ result
             PopBlock => 0,
-            Raise { kind } => {
+            RaiseVarArgs { kind } => {
                 // Stack effects for different raise kinds:
                 // - Reraise (0): gets from VM state, no stack pop
                 // - Raise (1): pops 1 exception
@@ -1848,7 +1823,7 @@ impl Instruction {
                 let UnpackExArgs { before, after } = args.get(arg);
                 -1 + before as i32 + 1 + after as i32
             }
-            PopException => 0,
+            PopExcept => 0,
             Reverse { .. } => 0,
             GetAwaitable => 0,
             BeforeAsyncWith => 1,
@@ -1932,47 +1907,10 @@ impl Instruction {
             };
 
         match self {
-            // Dummy/placeholder instructions
-            Cache => w!(CACHE),
-            Reserved3 | Reserved17 | Reserved140 | Reserved141 | Reserved142 | Reserved143
-            | Reserved144 | Reserved145 | Reserved146 | Reserved147 | Reserved148 => w!(RESERVED),
-            BinarySlice => w!(BINARY_SLICE),
-            EndFor => w!(END_FOR),
-            ExitInitCheck => w!(EXIT_INIT_CHECK),
-            GetYieldFromIter => w!(GET_YIELD_FROM_ITER),
-            InterpreterExit => w!(INTERPRETER_EXIT),
-            LoadAssertionError => w!(LOAD_ASSERTION_ERROR),
-            LoadLocals => w!(LOAD_LOCALS),
-            PushNull => w!(PUSH_NULL),
-            ReturnGenerator => w!(RETURN_GENERATOR),
-            StoreSlice => w!(STORE_SLICE),
-            UnaryInvert => w!(UNARY_INVERT),
-            UnaryNegative => w!(UNARY_NEGATIVE),
-            UnaryNot => w!(UNARY_NOT),
-            BuildConstKeyMap { size } => w!(BUILD_CONST_KEY_MAP, size),
-            CopyFreeVars { count } => w!(COPY_FREE_VARS, count),
-            DictMerge { index } => w!(DICT_MERGE, index),
-            EnterExecutor { index } => w!(ENTER_EXECUTOR, index),
-            JumpBackward { target } => w!(JUMP_BACKWARD, target),
-            JumpBackwardNoInterrupt { target } => w!(JUMP_BACKWARD_NO_INTERRUPT, target),
-            JumpForward { target } => w!(JUMP_FORWARD, target),
-            ListExtend { i } => w!(LIST_EXTEND, i),
-            LoadFastCheck(idx) => w!(LOAD_FAST_CHECK, varname = idx),
-            LoadFastLoadFast { arg } => w!(LOAD_FAST_LOAD_FAST, arg),
-            LoadFromDictOrDeref(idx) => w!(LOAD_FROM_DICT_OR_DEREF, cell_name = idx),
-            LoadFromDictOrGlobals(idx) => w!(LOAD_FROM_DICT_OR_GLOBALS, name = idx),
-            LoadSuperAttr { arg } => w!(LOAD_SUPER_ATTR, arg),
-            MakeCell(idx) => w!(MAKE_CELL, cell_name = idx),
-            PopJumpIfNone { target } => w!(POP_JUMP_IF_NONE, target),
-            PopJumpIfNotNone { target } => w!(POP_JUMP_IF_NOT_NONE, target),
-            SetUpdate { i } => w!(SET_UPDATE, i),
-            StoreFastStoreFast { arg } => w!(STORE_FAST_STORE_FAST, arg),
-
-            // Real instructions
             BeforeAsyncWith => w!(BEFORE_ASYNC_WITH),
             BeforeWith => w!(BEFORE_WITH),
             BinaryOp { op } => write!(f, "{:pad$}({})", "BINARY_OP", op.get(arg)),
-            BinarySubscript => w!(BINARY_SUBSCR),
+            BinarySubscr => w!(BINARY_SUBSCR),
             Break { target } => w!(BREAK, target),
             BuildList { size } => w!(BUILD_LIST, size),
             BuildListFromTuples { size } => w!(BUILD_LIST_FROM_TUPLES, size),
@@ -1985,9 +1923,9 @@ impl Instruction {
             BuildTuple { size } => w!(BUILD_TUPLE, size),
             BuildTupleFromIter => w!(BUILD_TUPLE_FROM_ITER),
             BuildTupleFromTuples { size } => w!(BUILD_TUPLE_FROM_TUPLES, size),
+            Call { nargs } => w!(CALL, nargs),
             CallFunctionEx { has_kwargs } => w!(CALL_FUNCTION_EX, has_kwargs),
-            CallFunctionKeyword { nargs } => w!(CALL_KW, nargs),
-            CallFunctionPositional { nargs } => w!(CALL, nargs),
+            CallKw { nargs } => w!(CALL_KW, nargs),
             CallIntrinsic1 { func } => w!(CALL_INTRINSIC_1, ?func),
             CallIntrinsic2 { func } => w!(CALL_INTRINSIC_2, ?func),
             CallMethodEx { has_kwargs } => w!(CALL_METHOD_EX, has_kwargs),
@@ -1996,7 +1934,7 @@ impl Instruction {
             CheckEgMatch => w!(CHECK_EG_MATCH),
             CheckExcMatch => w!(CHECK_EXC_MATCH),
             CleanupThrow => w!(CLEANUP_THROW),
-            CompareOperation { op } => w!(COMPARE_OP, ?op),
+            CompareOp { op } => w!(COMPARE_OP, ?op),
             ContainsOp(inv) => w!(CONTAINS_OP, ?inv),
             Continue { target } => w!(CONTINUE, target),
             ConvertValue { oparg } => write!(f, "{:pad$}{}", "CONVERT_VALUE", oparg.get(arg)),
@@ -2005,8 +1943,8 @@ impl Instruction {
             DeleteDeref(idx) => w!(DELETE_DEREF, cell_name = idx),
             DeleteFast(idx) => w!(DELETE_FAST, varname = idx),
             DeleteGlobal(idx) => w!(DELETE_GLOBAL, name = idx),
-            DeleteLocal(idx) => w!(DELETE_NAME, name = idx),
-            DeleteSubscript => w!(DELETE_SUBSCR),
+            DeleteName(idx) => w!(DELETE_NAME, name = idx),
+            DeleteSubscr => w!(DELETE_SUBSCR),
             DictUpdate { index } => w!(DICT_UPDATE, index),
             EndAsyncFor => w!(END_ASYNC_FOR),
             EndSend => w!(END_SEND),
@@ -2017,6 +1955,7 @@ impl Instruction {
             GetAIter => w!(GET_AITER),
             GetANext => w!(GET_ANEXT),
             GetAwaitable => w!(GET_AWAITABLE),
+            Reserved => w!(RESERVED),
             GetIter => w!(GET_ITER),
             GetLen => w!(GET_LEN),
             ImportFrom { idx } => w!(IMPORT_FROM, name = idx),
@@ -2037,7 +1976,7 @@ impl Instruction {
             LoadFastAndClear(idx) => w!(LOAD_FAST_AND_CLEAR, varname = idx),
             LoadGlobal(idx) => w!(LOAD_GLOBAL, name = idx),
             LoadMethod { idx } => w!(LOAD_METHOD, name = idx),
-            LoadNameAny(idx) => w!(LOAD_NAME, name = idx),
+            LoadName(idx) => w!(LOAD_NAME, name = idx),
             MakeFunction => w!(MAKE_FUNCTION),
             MapAdd { i } => w!(MAP_ADD, i),
             MatchClass(arg) => w!(MATCH_CLASS, arg),
@@ -2046,12 +1985,12 @@ impl Instruction {
             MatchSequence => w!(MATCH_SEQUENCE),
             Nop => w!(NOP),
             PopBlock => w!(POP_BLOCK),
-            PopException => w!(POP_EXCEPT),
+            PopExcept => w!(POP_EXCEPT),
             PopJumpIfFalse { target } => w!(POP_JUMP_IF_FALSE, target),
             PopJumpIfTrue { target } => w!(POP_JUMP_IF_TRUE, target),
             PopTop => w!(POP_TOP),
             PushExcInfo => w!(PUSH_EXC_INFO),
-            Raise { kind } => w!(RAISE_VARARGS, ?kind),
+            RaiseVarArgs { kind } => w!(RAISE_VARARGS, ?kind),
             Reraise { depth } => w!(RERAISE, depth),
             Resume { arg } => w!(RESUME, arg),
             ReturnConst { idx } => fmt_const("RETURN_CONST", arg, f, idx),
@@ -2061,7 +2000,7 @@ impl Instruction {
             SetAdd { i } => w!(SET_ADD, i),
             SetExcInfo => w!(SET_EXC_INFO),
             SetFunctionAttribute { attr } => w!(SET_FUNCTION_ATTRIBUTE, ?attr),
-            SetupAnnotation => w!(SETUP_ANNOTATIONS),
+            SetupAnnotations => w!(SETUP_ANNOTATIONS),
             StoreAttr { idx } => w!(STORE_ATTR, name = idx),
             StoreDeref(idx) => w!(STORE_DEREF, cell_name = idx),
             StoreFast(idx) => w!(STORE_FAST, varname = idx),
@@ -2073,14 +2012,17 @@ impl Instruction {
                 write!(f, " ({}, {})", store_idx.get(arg), load_idx.get(arg))
             }
             StoreGlobal(idx) => w!(STORE_GLOBAL, name = idx),
-            StoreLocal(idx) => w!(STORE_NAME, name = idx),
-            StoreSubscript => w!(STORE_SUBSCR),
+            StoreName(idx) => w!(STORE_NAME, name = idx),
+            StoreSubscr => w!(STORE_SUBSCR),
             Subscript => w!(SUBSCRIPT),
             Swap { index } => w!(SWAP, index),
             ToBool => w!(TO_BOOL),
             UnpackEx { args } => w!(UNPACK_EX, args),
             UnpackSequence { size } => w!(UNPACK_SEQUENCE, size),
             WithExceptStart => w!(WITH_EXCEPT_START),
+            UnaryInvert => w!(UNARY_INVERT),
+            UnaryNegative => w!(UNARY_NEGATIVE),
+            UnaryNot => w!(UNARY_NOT),
             YieldValue { arg } => w!(YIELD_VALUE, arg),
         }
     }

From 6b96d0ee67339cc140091276aa0a06e5be37caba Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 14:53:37 +0200
Subject: [PATCH 03/18] Fix `frame.rs`

---
 crates/vm/src/frame.rs | 45 ------------------------------------------
 1 file changed, 45 deletions(-)

diff --git a/crates/vm/src/frame.rs b/crates/vm/src/frame.rs
index fc56f50fb3d..87098af39e1 100644
--- a/crates/vm/src/frame.rs
+++ b/crates/vm/src/frame.rs
@@ -1779,51 +1779,6 @@ impl ExecutingFrame<'_> {
                 self.push_value(vm.ctx.new_bool(!value).into());
                 Ok(None)
             }
-            // Placeholder/dummy instructions - these should never be executed
-            bytecode::Instruction::Cache
-            | bytecode::Instruction::Reserved3
-            | bytecode::Instruction::Reserved17
-            | bytecode::Instruction::BinarySlice
-            | bytecode::Instruction::EndFor
-            | bytecode::Instruction::ExitInitCheck
-            | bytecode::Instruction::InterpreterExit
-            | bytecode::Instruction::LoadAssertionError
-            | bytecode::Instruction::LoadLocals
-            | bytecode::Instruction::PushNull
-            | bytecode::Instruction::ReturnGenerator
-            | bytecode::Instruction::StoreSlice
-            | bytecode::Instruction::BuildConstKeyMap { .. }
-            | bytecode::Instruction::CopyFreeVars { .. }
-            | bytecode::Instruction::DictMerge { .. }
-            | bytecode::Instruction::EnterExecutor { .. }
-            | bytecode::Instruction::JumpBackward { .. }
-            | bytecode::Instruction::JumpBackwardNoInterrupt { .. }
-            | bytecode::Instruction::JumpForward { .. }
-            | bytecode::Instruction::ListExtend { .. }
-            | bytecode::Instruction::LoadFastCheck(_)
-            | bytecode::Instruction::LoadFastLoadFast { .. }
-            | bytecode::Instruction::LoadFromDictOrDeref(_)
-            | bytecode::Instruction::LoadFromDictOrGlobals(_)
-            | bytecode::Instruction::LoadSuperAttr { .. }
-            | bytecode::Instruction::MakeCell(_)
-            | bytecode::Instruction::PopJumpIfNone { .. }
-            | bytecode::Instruction::PopJumpIfNotNone { .. }
-            | bytecode::Instruction::SetUpdate { .. }
-            | bytecode::Instruction::StoreFastStoreFast { .. }
-            | bytecode::Instruction::Reserved140
-            | bytecode::Instruction::Reserved141
-            | bytecode::Instruction::Reserved142
-            | bytecode::Instruction::Reserved143
-            | bytecode::Instruction::Reserved144
-            | bytecode::Instruction::Reserved145
-            | bytecode::Instruction::Reserved146
-            | bytecode::Instruction::Reserved147
-            | bytecode::Instruction::Reserved148 => {
-                unreachable!(
-                    "placeholder instruction should not be executed: {:?}",
-                    instruction
-                )
-            }
         }
     }
 

From 2a6672f089d857719672e2f19affd7574fa156ec Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 15:05:39 +0200
Subject: [PATCH 04/18] Fix codegen

---
 crates/codegen/src/compile.rs | 152 +++++++++++++++++-----------------
 1 file changed, 76 insertions(+), 76 deletions(-)

diff --git a/crates/codegen/src/compile.rs b/crates/codegen/src/compile.rs
index 66eb785e962..1b79c0d3617 100644
--- a/crates/codegen/src/compile.rs
+++ b/crates/codegen/src/compile.rs
@@ -494,7 +494,7 @@ impl Compiler {
                 }
                 ExprContext::Store => {
                     emit!(self, Instruction::BuildSlice { argc });
-                    emit!(self, Instruction::StoreSubscript);
+                    emit!(self, Instruction::StoreSubscr);
                 }
                 _ => unreachable!(),
             }
@@ -505,8 +505,8 @@ impl Compiler {
             // Emit appropriate instruction based on context
             match ctx {
                 ExprContext::Load => emit!(self, Instruction::Subscript),
-                ExprContext::Store => emit!(self, Instruction::StoreSubscript),
-                ExprContext::Del => emit!(self, Instruction::DeleteSubscript),
+                ExprContext::Store => emit!(self, Instruction::StoreSubscr),
+                ExprContext::Del => emit!(self, Instruction::DeleteSubscr),
                 ExprContext::Invalid => {
                     return Err(self.error(CodegenErrorType::SyntaxError(
                         "Invalid expression context".to_owned(),
@@ -1012,7 +1012,7 @@ impl Compiler {
                 // Stack when in FinallyEnd: [..., prev_exc, exc] or
                 // [..., prev_exc, exc, return_value] if preserve_tos
                 // Note: No lasti here - it's only pushed for cleanup handler exceptions
-                // We need to pop: exc, prev_exc (via PopException)
+                // We need to pop: exc, prev_exc (via PopExcept)
                 if preserve_tos {
                     emit!(self, Instruction::Swap { index: 2 });
                 }
@@ -1020,7 +1020,7 @@ impl Compiler {
                 if preserve_tos {
                     emit!(self, Instruction::Swap { index: 2 });
                 }
-                emit!(self, Instruction::PopException); // prev_exc is restored
+                emit!(self, Instruction::PopExcept); // prev_exc is restored
             }
 
             FBlockType::With | FBlockType::AsyncWith => {
@@ -1039,7 +1039,7 @@ impl Compiler {
                 self.emit_load_const(ConstantData::None);
                 self.emit_load_const(ConstantData::None);
                 self.emit_load_const(ConstantData::None);
-                emit!(self, Instruction::CallFunctionPositional { nargs: 3 });
+                emit!(self, Instruction::Call { nargs: 3 });
 
                 // For async with, await the result
                 if matches!(info.fb_type, FBlockType::AsyncWith) {
@@ -1056,7 +1056,7 @@ impl Compiler {
                 if preserve_tos {
                     emit!(self, Instruction::Swap { index: 2 });
                 }
-                emit!(self, Instruction::PopException);
+                emit!(self, Instruction::PopExcept);
 
                 // If there's an exception name, clean it up
                 if let FBlockDatum::ExceptionName(ref name) = info.fb_datum {
@@ -1341,7 +1341,7 @@ impl Compiler {
         }
 
         if Self::find_ann(statements) {
-            emit!(self, Instruction::SetupAnnotation);
+            emit!(self, Instruction::SetupAnnotations);
         }
 
         self.compile_statements(statements)?;
@@ -1361,7 +1361,7 @@ impl Compiler {
         self.symbol_table_stack.push(symbol_table);
 
         if Self::find_ann(body) {
-            emit!(self, Instruction::SetupAnnotation);
+            emit!(self, Instruction::SetupAnnotations);
         }
 
         if let Some((last, body)) = body.split_last() {
@@ -1593,9 +1593,9 @@ impl Compiler {
             NameOp::Name => {
                 let idx = self.get_global_name_index(&name);
                 let op = match usage {
-                    NameUsage::Load => Instruction::LoadNameAny,
-                    NameUsage::Store => Instruction::StoreLocal,
-                    NameUsage::Delete => Instruction::DeleteLocal,
+                    NameUsage::Load => Instruction::LoadName,
+                    NameUsage::Store => Instruction::StoreName,
+                    NameUsage::Delete => Instruction::DeleteName,
                 };
                 self.emit_arg(idx, op);
             }
@@ -1814,7 +1814,7 @@ impl Compiler {
                     None => bytecode::RaiseKind::BareRaise,
                 };
                 self.set_source_range(*range);
-                emit!(self, Instruction::Raise { kind });
+                emit!(self, Instruction::RaiseVarArgs { kind });
             }
             Stmt::Try(StmtTry {
                 body,
@@ -1877,15 +1877,15 @@ impl Compiler {
                     match msg {
                         Some(e) => {
                             self.compile_expression(e)?;
-                            emit!(self, Instruction::CallFunctionPositional { nargs: 1 });
+                            emit!(self, Instruction::Call { nargs: 1 });
                         }
                         None => {
-                            emit!(self, Instruction::CallFunctionPositional { nargs: 0 });
+                            emit!(self, Instruction::Call { nargs: 0 });
                         }
                     }
                     emit!(
                         self,
-                        Instruction::Raise {
+                        Instruction::RaiseVarArgs {
                             kind: bytecode::RaiseKind::Raise,
                         }
                     );
@@ -2101,7 +2101,7 @@ impl Compiler {
     fn apply_decorators(&mut self, decorator_list: &[Decorator]) {
         // Apply decorators:
         for _ in decorator_list {
-            emit!(self, Instruction::CallFunctionPositional { nargs: 1 });
+            emit!(self, Instruction::Call { nargs: 1 });
         }
     }
 
@@ -2143,7 +2143,7 @@ impl Compiler {
         self.make_closure(code, bytecode::MakeFunctionFlags::empty())?;
 
         // Call the function immediately
-        emit!(self, Instruction::CallFunctionPositional { nargs: 0 });
+        emit!(self, Instruction::Call { nargs: 0 });
 
         Ok(())
     }
@@ -2383,7 +2383,7 @@ impl Compiler {
                 // which then properly restores prev_exc before going to outer handler
                 emit!(
                     self,
-                    Instruction::Raise {
+                    Instruction::RaiseVarArgs {
                         kind: bytecode::RaiseKind::ReraiseFromStack
                     }
                 );
@@ -2395,10 +2395,10 @@ impl Compiler {
             if let Some(cleanup) = finally_cleanup_block {
                 self.switch_to_block(cleanup);
                 emit!(self, Instruction::CopyItem { index: 3_u32 });
-                emit!(self, Instruction::PopException);
+                emit!(self, Instruction::PopExcept);
                 emit!(
                     self,
-                    Instruction::Raise {
+                    Instruction::RaiseVarArgs {
                         kind: bytecode::RaiseKind::ReraiseFromStack
                     }
                 );
@@ -2443,7 +2443,7 @@ impl Compiler {
         )?;
 
         // Exception is on top of stack now, pushed by unwind_blocks
-        // PUSH_EXC_INFO transforms [exc] -> [prev_exc, exc] for PopException
+        // PUSH_EXC_INFO transforms [exc] -> [prev_exc, exc] for PopExcept
         emit!(self, Instruction::PushExcInfo);
         for handler in handlers {
             let ExceptHandler::ExceptHandler(ExceptHandlerExceptHandler {
@@ -2528,7 +2528,7 @@ impl Compiler {
                 // which does COPY 3; POP_EXCEPT; RERAISE
                 emit!(
                     self,
-                    Instruction::Raise {
+                    Instruction::RaiseVarArgs {
                         kind: bytecode::RaiseKind::ReraiseFromStack,
                     }
                 );
@@ -2541,7 +2541,7 @@ impl Compiler {
             // POP_BLOCK (HandlerCleanup) then POP_BLOCK (SETUP_CLEANUP)
             // followed by POP_EXCEPT
             self.pop_fblock(FBlockType::ExceptionHandler);
-            emit!(self, Instruction::PopException);
+            emit!(self, Instruction::PopExcept);
 
             // Delete the exception variable if it was bound (normal path)
             if let Some(alias) = name {
@@ -2581,7 +2581,7 @@ impl Compiler {
         // NOTE: We emit RERAISE 0 BEFORE popping fblock so it is within cleanup handler scope
         emit!(
             self,
-            Instruction::Raise {
+            Instruction::RaiseVarArgs {
                 kind: bytecode::RaiseKind::ReraiseFromStack,
             }
         );
@@ -2597,10 +2597,10 @@ impl Compiler {
         // RERAISE 1: reraise with lasti
         self.switch_to_block(cleanup_block);
         emit!(self, Instruction::CopyItem { index: 3_u32 });
-        emit!(self, Instruction::PopException);
+        emit!(self, Instruction::PopExcept);
         emit!(
             self,
-            Instruction::Raise {
+            Instruction::RaiseVarArgs {
                 kind: bytecode::RaiseKind::ReraiseFromStack,
             }
         );
@@ -2680,7 +2680,7 @@ impl Compiler {
             // Stack: [lasti, prev_exc, exc] - exception is on top
             emit!(
                 self,
-                Instruction::Raise {
+                Instruction::RaiseVarArgs {
                     kind: bytecode::RaiseKind::ReraiseFromStack,
                 }
             );
@@ -2698,11 +2698,11 @@ impl Compiler {
             // COPY 3: copy the exception from position 3
             emit!(self, Instruction::CopyItem { index: 3_u32 });
             // POP_EXCEPT: restore prev_exc as current exception
-            emit!(self, Instruction::PopException);
+            emit!(self, Instruction::PopExcept);
             // RERAISE 1: reraise with lasti from stack
             emit!(
                 self,
-                Instruction::Raise {
+                Instruction::RaiseVarArgs {
                     kind: bytecode::RaiseKind::ReraiseFromStack,
                 }
             );
@@ -2971,7 +2971,7 @@ impl Compiler {
 
         // POP_BLOCK - no-op for us with exception tables (fblocks handle this)
         // POP_EXCEPT - restore previous exception context
-        emit!(self, Instruction::PopException);
+        emit!(self, Instruction::PopExcept);
         // Stack: []
 
         if !finalbody.is_empty() {
@@ -2990,7 +2990,7 @@ impl Compiler {
         // Stack: [result, prev_exc]
 
         // POP_EXCEPT
-        emit!(self, Instruction::PopException);
+        emit!(self, Instruction::PopExcept);
         // Stack: [result]
 
         // RERAISE 0
@@ -3326,13 +3326,13 @@ impl Compiler {
                 );
                 emit!(
                     self,
-                    Instruction::CallFunctionPositional {
+                    Instruction::Call {
                         nargs: num_typeparam_args as u32
                     }
                 );
             } else {
                 // No arguments, just call the closure
-                emit!(self, Instruction::CallFunctionPositional { nargs: 0 });
+                emit!(self, Instruction::Call { nargs: 0 });
             }
         }
 
@@ -3570,20 +3570,20 @@ impl Compiler {
         let dunder_name = self.name("__name__");
         emit!(self, Instruction::LoadGlobal(dunder_name));
         let dunder_module = self.name("__module__");
-        emit!(self, Instruction::StoreLocal(dunder_module));
+        emit!(self, Instruction::StoreName(dunder_module));
 
         // Store __qualname__
         self.emit_load_const(ConstantData::Str {
             value: qualname.into(),
         });
         let qualname_name = self.name("__qualname__");
-        emit!(self, Instruction::StoreLocal(qualname_name));
+        emit!(self, Instruction::StoreName(qualname_name));
 
         // Store __doc__ only if there's an explicit docstring
         if let Some(doc) = doc_str {
             self.emit_load_const(ConstantData::Str { value: doc.into() });
             let doc_name = self.name("__doc__");
-            emit!(self, Instruction::StoreLocal(doc_name));
+            emit!(self, Instruction::StoreName(doc_name));
         }
 
         // Store __firstlineno__ (new in Python 3.12+)
@@ -3591,22 +3591,22 @@ impl Compiler {
             value: BigInt::from(firstlineno),
         });
         let firstlineno_name = self.name("__firstlineno__");
-        emit!(self, Instruction::StoreLocal(firstlineno_name));
+        emit!(self, Instruction::StoreName(firstlineno_name));
 
         // Set __type_params__ if we have type parameters
         if type_params.is_some() {
             // Load .type_params from enclosing scope
             let dot_type_params = self.name(".type_params");
-            emit!(self, Instruction::LoadNameAny(dot_type_params));
+            emit!(self, Instruction::LoadName(dot_type_params));
 
             // Store as __type_params__
             let dunder_type_params = self.name("__type_params__");
-            emit!(self, Instruction::StoreLocal(dunder_type_params));
+            emit!(self, Instruction::StoreName(dunder_type_params));
         }
 
         // Setup annotations if needed
         if Self::find_ann(body) {
-            emit!(self, Instruction::SetupAnnotation);
+            emit!(self, Instruction::SetupAnnotations);
         }
 
         // 3. Compile the class body
@@ -3626,7 +3626,7 @@ impl Compiler {
             emit!(self, Instruction::LoadClosure(classcell_idx.to_u32()));
             emit!(self, Instruction::CopyItem { index: 1_u32 });
             let classcell = self.name("__classcell__");
-            emit!(self, Instruction::StoreLocal(classcell));
+            emit!(self, Instruction::StoreName(classcell));
         } else {
             self.emit_load_const(ConstantData::None);
         }
@@ -3668,7 +3668,7 @@ impl Compiler {
             // Compile type parameters and store as .type_params
             self.compile_type_params(type_params.unwrap())?;
             let dot_type_params = self.name(".type_params");
-            emit!(self, Instruction::StoreLocal(dot_type_params));
+            emit!(self, Instruction::StoreName(dot_type_params));
         }
 
         // Step 2: Compile class body (always done, whether generic or not)
@@ -3689,21 +3689,21 @@ impl Compiler {
             let dot_generic_base = self.name(".generic_base");
 
             // Create .generic_base
-            emit!(self, Instruction::LoadNameAny(dot_type_params));
+            emit!(self, Instruction::LoadName(dot_type_params));
             emit!(
                 self,
                 Instruction::CallIntrinsic1 {
                     func: bytecode::IntrinsicFunction1::SubscriptGeneric
                 }
             );
-            emit!(self, Instruction::StoreLocal(dot_generic_base));
+            emit!(self, Instruction::StoreName(dot_generic_base));
 
             // Generate class creation code
             emit!(self, Instruction::LoadBuildClass);
 
             // Set up the class function with type params
             let mut func_flags = bytecode::MakeFunctionFlags::empty();
-            emit!(self, Instruction::LoadNameAny(dot_type_params));
+            emit!(self, Instruction::LoadName(dot_type_params));
             func_flags |= bytecode::MakeFunctionFlags::TYPE_PARAMS;
 
             // Create class function with closure
@@ -3721,7 +3721,7 @@ impl Compiler {
             };
 
             // Load .generic_base as the last base
-            emit!(self, Instruction::LoadNameAny(dot_generic_base));
+            emit!(self, Instruction::LoadName(dot_generic_base));
 
             let nargs = 2 + u32::try_from(base_count).expect("too many base classes") + 1; // function, name, bases..., generic_base
 
@@ -3739,14 +3739,14 @@ impl Compiler {
                 }
                 emit!(
                     self,
-                    Instruction::CallFunctionKeyword {
+                    Instruction::CallKw {
                         nargs: nargs
                             + u32::try_from(arguments.keywords.len())
                                 .expect("too many keyword arguments")
                     }
                 );
             } else {
-                emit!(self, Instruction::CallFunctionPositional { nargs });
+                emit!(self, Instruction::Call { nargs });
             }
 
             // Return the created class
@@ -3757,7 +3757,7 @@ impl Compiler {
 
             // Execute the type params function
             self.make_closure(type_params_code, bytecode::MakeFunctionFlags::empty())?;
-            emit!(self, Instruction::CallFunctionPositional { nargs: 0 });
+            emit!(self, Instruction::Call { nargs: 0 });
         } else {
             // Non-generic class: standard path
             emit!(self, Instruction::LoadBuildClass);
@@ -3924,7 +3924,7 @@ impl Compiler {
         self.emit_load_const(ConstantData::None);
         self.emit_load_const(ConstantData::None);
         self.emit_load_const(ConstantData::None);
-        emit!(self, Instruction::CallFunctionPositional { nargs: 3 });
+        emit!(self, Instruction::Call { nargs: 3 });
         if is_async {
             emit!(self, Instruction::GetAwaitable);
             self.emit_load_const(ConstantData::None);
@@ -4000,7 +4000,7 @@ impl Compiler {
         // Need to pop: True, exc, prev_exc, __exit__
         self.switch_to_block(suppress_block);
         emit!(self, Instruction::PopTop); // pop True (TO_BOOL result)
-        emit!(self, Instruction::PopException); // pop exc and restore prev_exc
+        emit!(self, Instruction::PopExcept); // pop exc and restore prev_exc
         emit!(self, Instruction::PopTop); // pop __exit__
         emit!(self, Instruction::PopTop); // pop lasti
         emit!(
@@ -4022,7 +4022,7 @@ impl Compiler {
         // If we cleared fblock, exceptions here would propagate uncaught.
         self.switch_to_block(cleanup_block);
         emit!(self, Instruction::CopyItem { index: 3 });
-        emit!(self, Instruction::PopException);
+        emit!(self, Instruction::PopExcept);
         emit!(self, Instruction::Reraise { depth: 1 });
 
         // ===== After block =====
@@ -4344,7 +4344,7 @@ impl Compiler {
                 );
             }
             // Use BINARY_OP/NB_SUBSCR to extract the element.
-            emit!(self, Instruction::BinarySubscript);
+            emit!(self, Instruction::BinarySubscr);
             // Compile the subpattern in irrefutable mode.
             self.compile_pattern_subpattern(pattern, pc)?;
         }
@@ -4597,7 +4597,7 @@ impl Compiler {
             // Stack: [subject, len, size]
             emit!(
                 self,
-                Instruction::CompareOperation {
+                Instruction::CompareOp {
                     op: ComparisonOperator::GreaterOrEqual
                 }
             );
@@ -4723,7 +4723,7 @@ impl Compiler {
                 // Stack: [rest_dict, k1, ..., kn, rest_dict]
                 emit!(self, Instruction::Swap { index: 2 });
                 // Stack: [rest_dict, k1, ..., kn-1, rest_dict, kn]
-                emit!(self, Instruction::DeleteSubscript);
+                emit!(self, Instruction::DeleteSubscr);
                 // Stack: [rest_dict, k1, ..., kn-1] (removed kn from rest_dict)
                 remaining -= 1;
             }
@@ -4901,7 +4901,7 @@ impl Compiler {
             self.emit_load_const(ConstantData::Integer { value: size.into() });
             emit!(
                 self,
-                Instruction::CompareOperation {
+                Instruction::CompareOp {
                     op: ComparisonOperator::Equal
                 }
             );
@@ -4914,7 +4914,7 @@ impl Compiler {
             });
             emit!(
                 self,
-                Instruction::CompareOperation {
+                Instruction::CompareOp {
                     op: ComparisonOperator::GreaterOrEqual
                 }
             );
@@ -4943,7 +4943,7 @@ impl Compiler {
         self.compile_expression(&p.value)?;
         emit!(
             self,
-            Instruction::CompareOperation {
+            Instruction::CompareOp {
                 op: bytecode::ComparisonOperator::Equal
             }
         );
@@ -5087,13 +5087,13 @@ impl Compiler {
     fn compile_addcompare(&mut self, op: &CmpOp) {
         use bytecode::ComparisonOperator::*;
         match op {
-            CmpOp::Eq => emit!(self, Instruction::CompareOperation { op: Equal }),
-            CmpOp::NotEq => emit!(self, Instruction::CompareOperation { op: NotEqual }),
-            CmpOp::Lt => emit!(self, Instruction::CompareOperation { op: Less }),
-            CmpOp::LtE => emit!(self, Instruction::CompareOperation { op: LessOrEqual }),
-            CmpOp::Gt => emit!(self, Instruction::CompareOperation { op: Greater }),
+            CmpOp::Eq => emit!(self, Instruction::CompareOp { op: Equal }),
+            CmpOp::NotEq => emit!(self, Instruction::CompareOp { op: NotEqual }),
+            CmpOp::Lt => emit!(self, Instruction::CompareOp { op: Less }),
+            CmpOp::LtE => emit!(self, Instruction::CompareOp { op: LessOrEqual }),
+            CmpOp::Gt => emit!(self, Instruction::CompareOp { op: Greater }),
             CmpOp::GtE => {
-                emit!(self, Instruction::CompareOperation { op: GreaterOrEqual })
+                emit!(self, Instruction::CompareOp { op: GreaterOrEqual })
             }
             CmpOp::In => emit!(self, Instruction::ContainsOp(Invert::No)),
             CmpOp::NotIn => emit!(self, Instruction::ContainsOp(Invert::Yes)),
@@ -5228,11 +5228,11 @@ impl Compiler {
         if let Expr::Name(ExprName { id, .. }) = &target {
             // Store as dict entry in __annotations__ dict:
             let annotations = self.name("__annotations__");
-            emit!(self, Instruction::LoadNameAny(annotations));
+            emit!(self, Instruction::LoadName(annotations));
             self.emit_load_const(ConstantData::Str {
                 value: self.mangle(id.as_str()).into_owned().into(),
             });
-            emit!(self, Instruction::StoreSubscript);
+            emit!(self, Instruction::StoreSubscr);
         } else {
             // Drop annotation if not assigned to simple identifier.
             emit!(self, Instruction::PopTop);
@@ -5369,7 +5369,7 @@ impl Compiler {
                 // stack: CONTAINER SLICE RESULT
                 emit!(self, Instruction::Swap { index: 3 });
                 emit!(self, Instruction::Swap { index: 2 });
-                emit!(self, Instruction::StoreSubscript);
+                emit!(self, Instruction::StoreSubscr);
             }
             AugAssignKind::Attr { idx } => {
                 // stack: CONTAINER RESULT
@@ -6117,9 +6117,9 @@ impl Compiler {
     fn compile_normal_call(&mut self, ty: CallType) {
         match ty {
             CallType::Positional { nargs } => {
-                emit!(self, Instruction::CallFunctionPositional { nargs })
+                emit!(self, Instruction::Call { nargs })
             }
-            CallType::Keyword { nargs } => emit!(self, Instruction::CallFunctionKeyword { nargs }),
+            CallType::Keyword { nargs } => emit!(self, Instruction::CallKw { nargs }),
             CallType::Ex { has_kwargs } => emit!(self, Instruction::CallFunctionEx { has_kwargs }),
         }
     }
@@ -6431,7 +6431,7 @@ impl Compiler {
         };
 
         // Call just created <listcomp> function:
-        emit!(self, Instruction::CallFunctionPositional { nargs: 1 });
+        emit!(self, Instruction::Call { nargs: 1 });
         if is_async_list_set_dict_comprehension {
             emit!(self, Instruction::GetAwaitable);
             self.emit_load_const(ConstantData::None);
@@ -6631,7 +6631,7 @@ impl Compiler {
             // Re-raise the exception
             emit!(
                 self,
-                Instruction::Raise {
+                Instruction::RaiseVarArgs {
                     kind: bytecode::RaiseKind::ReraiseFromStack
                 }
             );
@@ -6850,7 +6850,7 @@ impl Compiler {
                     self.emit_load_const(ConstantData::None);
                     self.emit_load_const(ConstantData::None);
                     self.emit_load_const(ConstantData::None);
-                    emit!(self, Instruction::CallFunctionPositional { nargs: 3 });
+                    emit!(self, Instruction::Call { nargs: 3 });
 
                     if is_async {
                         emit!(self, Instruction::GetAwaitable);
@@ -6861,7 +6861,7 @@ impl Compiler {
                     emit!(self, Instruction::PopTop);
                 }
                 UnwindAction::HandlerCleanup => {
-                    emit!(self, Instruction::PopException);
+                    emit!(self, Instruction::PopExcept);
                 }
                 UnwindAction::FinallyTry { body, fblock_idx } => {
                     // compile finally body inline
@@ -6880,9 +6880,9 @@ impl Compiler {
                 UnwindAction::FinallyEnd => {
                     // Stack when in FinallyEnd: [..., prev_exc, exc]
                     // Note: No lasti here - it's only pushed for cleanup handler exceptions
-                    // We need to pop: exc, prev_exc (via PopException)
+                    // We need to pop: exc, prev_exc (via PopExcept)
                     emit!(self, Instruction::PopTop); // exc
-                    emit!(self, Instruction::PopException); // prev_exc is restored
+                    emit!(self, Instruction::PopExcept); // prev_exc is restored
                 }
                 UnwindAction::PopValue => {
                     // Pop the return value - continue/break cancels the pending return

From c5eab6a0c956c6bebe53d5fd3e7aa93db1fb859b Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 16:04:54 +0200
Subject: [PATCH 05/18] re add GetYieldFromIter

---
 crates/compiler-core/src/bytecode.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index db12ac2bbc2..757c8d1bc19 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -692,6 +692,7 @@ pub enum Instruction {
     GetANext = 18,
     GetIter = 19,
     GetLen = 20,
+    GetYieldFromIter = 21,
     LoadBuildClass = 24,
     MakeFunction = 26,
     MatchKeys = 27,
@@ -890,7 +891,6 @@ pub enum Instruction {
     } = 133,
     SetExcInfo = 134,
     Subscript = 135,
-
     // ===== Pseudo Opcodes (252+) ======
     Jump {
         target: Arg<Label>,
@@ -1837,6 +1837,7 @@ impl Instruction {
             UnaryInvert => 0,
             UnaryNegative => 0,
             UnaryNot => 0,
+            GetYieldFromIter => 0,
         }
     }
 
@@ -2024,6 +2025,7 @@ impl Instruction {
             UnaryNegative => w!(UNARY_NEGATIVE),
             UnaryNot => w!(UNARY_NOT),
             YieldValue { arg } => w!(YIELD_VALUE, arg),
+            GetYieldFromIter => w!(GET_YIELD_FROM_ITER),
         }
     }
 }

From c56c91f7f92a5be0d8d31e66e91ae8a0d09580c6 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 16:11:15 +0200
Subject: [PATCH 06/18] Fix `frame.rs`

---
 crates/vm/src/frame.rs | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/crates/vm/src/frame.rs b/crates/vm/src/frame.rs
index 87098af39e1..105a9fa36a7 100644
--- a/crates/vm/src/frame.rs
+++ b/crates/vm/src/frame.rs
@@ -391,7 +391,7 @@ impl ExecutingFrame<'_> {
                     // Instruction::Reraise are reraise operations that should not add
                     // new traceback entries
                     let is_reraise = match op {
-                        bytecode::Instruction::Raise { kind } => matches!(
+                        bytecode::Instruction::RaiseVarArgs { kind } => matches!(
                             kind.get(arg),
                             bytecode::RaiseKind::BareRaise | bytecode::RaiseKind::ReraiseFromStack
                         ),
@@ -610,7 +610,7 @@ impl ExecutingFrame<'_> {
                 Ok(None)
             }
             bytecode::Instruction::BinaryOp { op } => self.execute_bin_op(vm, op.get(arg)),
-            bytecode::Instruction::BinarySubscript => {
+            bytecode::Instruction::BinarySubscr => {
                 let key = self.pop_value();
                 let container = self.pop_value();
                 self.state
@@ -711,11 +711,11 @@ impl ExecutingFrame<'_> {
                 let args = self.collect_ex_args(vm, has_kwargs.get(arg))?;
                 self.execute_call(args, vm)
             }
-            bytecode::Instruction::CallFunctionKeyword { nargs } => {
+            bytecode::Instruction::CallKw { nargs } => {
                 let args = self.collect_keyword_args(nargs.get(arg));
                 self.execute_call(args, vm)
             }
-            bytecode::Instruction::CallFunctionPositional { nargs } => {
+            bytecode::Instruction::Call { nargs } => {
                 let args = self.collect_positional_args(nargs.get(arg));
                 self.execute_call(args, vm)
             }
@@ -753,7 +753,7 @@ impl ExecutingFrame<'_> {
                 self.push_value(matched);
                 Ok(None)
             }
-            bytecode::Instruction::CompareOperation { op } => self.execute_compare(vm, op.get(arg)),
+            bytecode::Instruction::CompareOp { op } => self.execute_compare(vm, op.get(arg)),
             bytecode::Instruction::ContainsOp(invert) => {
                 let b = self.pop_value();
                 let a = self.pop_value();
@@ -822,7 +822,7 @@ impl ExecutingFrame<'_> {
                 }
                 Ok(None)
             }
-            bytecode::Instruction::DeleteLocal(idx) => {
+            bytecode::Instruction::DeleteName(idx) => {
                 let name = self.code.names[idx.get(arg) as usize];
                 let res = self.locals.mapping().ass_subscript(name, None, vm);
 
@@ -835,7 +835,7 @@ impl ExecutingFrame<'_> {
                 }
                 Ok(None)
             }
-            bytecode::Instruction::DeleteSubscript => self.execute_delete_subscript(vm),
+            bytecode::Instruction::DeleteSubscr => self.execute_delete_subscript(vm),
             bytecode::Instruction::DictUpdate { index } => {
                 // Stack before: [..., dict, ..., source]  (source at TOS)
                 // Stack after:  [..., dict, ...]  (source consumed)
@@ -1192,7 +1192,7 @@ impl ExecutingFrame<'_> {
                 self.push_value(func);
                 Ok(None)
             }
-            bytecode::Instruction::LoadNameAny(idx) => {
+            bytecode::Instruction::LoadName(idx) => {
                 let name = self.code.names[idx.get(arg) as usize];
                 let result = self.locals.mapping().subscript(name, vm);
                 match result {
@@ -1428,7 +1428,7 @@ impl ExecutingFrame<'_> {
             bytecode::Instruction::Nop => Ok(None),
             // PopBlock is now a pseudo-instruction - exception table handles this
             bytecode::Instruction::PopBlock => Ok(None),
-            bytecode::Instruction::PopException => {
+            bytecode::Instruction::PopExcept => {
                 // Pop prev_exc from value stack and restore it
                 let prev_exc = self.pop_value();
                 if vm.is_none(&prev_exc) {
@@ -1457,7 +1457,7 @@ impl ExecutingFrame<'_> {
                 self.pop_value();
                 Ok(None)
             }
-            bytecode::Instruction::Raise { kind } => self.execute_raise(vm, kind.get(arg)),
+            bytecode::Instruction::RaiseVarArgs { kind } => self.execute_raise(vm, kind.get(arg)),
             bytecode::Instruction::Resume { arg: resume_arg } => {
                 // Resume execution after yield, await, or at function start
                 // In CPython, this checks instrumentation and eval breaker
@@ -1559,7 +1559,7 @@ impl ExecutingFrame<'_> {
             bytecode::Instruction::SetFunctionAttribute { attr } => {
                 self.execute_set_function_attribute(vm, attr.get(arg))
             }
-            bytecode::Instruction::SetupAnnotation => self.setup_annotations(vm),
+            bytecode::Instruction::SetupAnnotations => self.setup_annotations(vm),
             bytecode::Instruction::BeforeWith => {
                 // TOS: context_manager
                 // Result: [..., __exit__, __enter__ result]
@@ -1621,13 +1621,13 @@ impl ExecutingFrame<'_> {
                     .set_item(self.code.names[idx.get(arg) as usize], value, vm)?;
                 Ok(None)
             }
-            bytecode::Instruction::StoreLocal(idx) => {
+            bytecode::Instruction::StoreName(idx) => {
                 let name = self.code.names[idx.get(arg) as usize];
                 let value = self.pop_value();
                 self.locals.mapping().ass_subscript(name, Some(value), vm)?;
                 Ok(None)
             }
-            bytecode::Instruction::StoreSubscript => self.execute_store_subscript(vm),
+            bytecode::Instruction::StoreSubscr => self.execute_store_subscript(vm),
             bytecode::Instruction::Subscript => self.execute_subscript(vm),
             bytecode::Instruction::Swap { index } => {
                 let len = self.state.stack.len();
@@ -1779,6 +1779,9 @@ impl ExecutingFrame<'_> {
                 self.push_value(vm.ctx.new_bool(!value).into());
                 Ok(None)
             }
+            bytecode::Instruction::Reserved => {
+                unreachable!("{instruction:?} instruction should not be executed")
+            }
         }
     }
 

From 04f6d421e0a0c2f4f06dcce29ceb56ecae26ea69 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 16:14:47 +0200
Subject: [PATCH 07/18] Fix `opcode.rs`

---
 crates/stdlib/src/opcode.rs | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/crates/stdlib/src/opcode.rs b/crates/stdlib/src/opcode.rs
index cf6502181a7..99cc4130b08 100644
--- a/crates/stdlib/src/opcode.rs
+++ b/crates/stdlib/src/opcode.rs
@@ -69,16 +69,16 @@ mod opcode {
                     Instruction::try_from(opcode as u8),
                     Ok(Instruction::DeleteAttr { .. }
                         | Instruction::DeleteGlobal(_)
-                        | Instruction::DeleteLocal(_)
+                        | Instruction::DeleteName(_)
                         | Instruction::ImportFrom { .. }
                         | Instruction::ImportName { .. }
                         | Instruction::LoadAttr { .. }
                         | Instruction::LoadGlobal(_)
                         | Instruction::LoadMethod { .. }
-                        | Instruction::LoadNameAny(_)
+                        | Instruction::LoadName(_)
                         | Instruction::StoreAttr { .. }
                         | Instruction::StoreGlobal(_)
-                        | Instruction::StoreLocal(_))
+                        | Instruction::StoreName(_))
                 )
         }
 
@@ -97,8 +97,6 @@ mod opcode {
                         | Instruction::Jump { .. }
                         | Instruction::PopJumpIfFalse { .. }
                         | Instruction::PopJumpIfTrue { .. }
-                        | Instruction::PopJumpIfNone { .. }
-                        | Instruction::PopJumpIfNotNone { .. }
                         | Instruction::Send { .. })
                 )
         }

From a7a0eda35a3021f288d818cb9e2a521e294b6f40 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 16:27:27 +0200
Subject: [PATCH 08/18] Fix `TryFrom<u8>` for `Instruction`

---
 crates/compiler-core/src/bytecode.rs | 41 ++++++++++++++++++----------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index 757c8d1bc19..c5f0708eb0a 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -902,28 +902,39 @@ pub enum Instruction {
     PopBlock = 255,                  // CPython uses pseudo-op 263
 }
 
-// This must be kept up to date to avoid marshaling errors
-const LAST_INSTRUCTION: Instruction = Instruction::Resume { arg: Arg::marker() };
-
 const _: () = assert!(mem::size_of::<Instruction>() == 1);
 
-impl From<Instruction> for u8 {
-    #[inline]
-    fn from(ins: Instruction) -> Self {
-        // SAFETY: there's no padding bits
-        unsafe { core::mem::transmute::<Instruction, Self>(ins) }
-    }
-}
-
 impl TryFrom<u8> for Instruction {
     type Error = MarshalError;
 
     #[inline]
     fn try_from(value: u8) -> Result<Self, MarshalError> {
-        if value <= u8::from(LAST_INSTRUCTION) {
-            Ok(unsafe { core::mem::transmute::<u8, Self>(value) })
-        } else {
-            Err(MarshalError::InvalidBytecode)
+        match value {
+            1
+            | 2
+            | 5..=10
+            | 12
+            | 14..=21
+            | 24
+            | 26..=33
+            | 36
+            | 37
+            | 39..=45
+            | 47..=61
+            | 63..=67
+            | 69
+            | 71..=76
+            | 80
+            | 82..=86
+            | 91
+            | 92
+            | 95..=97
+            | 100..=106
+            | 108..=111
+            | 113..=135
+            | 149
+            | 252..=255 => Ok(unsafe { core::mem::transmute::<u8, Self>(value) }),
+            _ => Err(Self::Error::InvalidBytecode),
         }
     }
 }

From 164664376d8a53730a0e959f8e8e27f6ccee6d09 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 16:29:40 +0200
Subject: [PATCH 09/18] Mark failing tests

---
 Lib/test/test__opcode.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Lib/test/test__opcode.py b/Lib/test/test__opcode.py
index 60dcdc6cd70..949174a2739 100644
--- a/Lib/test/test__opcode.py
+++ b/Lib/test/test__opcode.py
@@ -16,6 +16,7 @@ def check_bool_function_result(self, func, ops, expected):
                 self.assertIsInstance(func(op), bool)
                 self.assertEqual(func(op), expected)
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON; Only supporting u8 ATM
     def test_invalid_opcodes(self):
         invalid = [-100, -1, 255, 512, 513, 1000]
         self.check_bool_function_result(_opcode.is_valid, invalid, False)
@@ -57,6 +58,7 @@ def check_function(self, func, expected):
 
 
 class StackEffectTests(unittest.TestCase):
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: ValueError not raised by stack_effect
     def test_stack_effect(self):
         self.assertEqual(stack_effect(dis.opmap['POP_TOP']), -1)
         self.assertEqual(stack_effect(dis.opmap['BUILD_SLICE'], 0), -1)

From e166fda08d0fa31bdf1491c1cfb6f80b2e432528 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Tue, 6 Jan 2026 16:33:57 +0200
Subject: [PATCH 10/18] fix jit

---
 crates/jit/src/instructions.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/jit/src/instructions.rs b/crates/jit/src/instructions.rs
index d6e3a07e111..4406cf39d49 100644
--- a/crates/jit/src/instructions.rs
+++ b/crates/jit/src/instructions.rs
@@ -454,7 +454,7 @@ impl<'a, 'b> FunctionCompiler<'a, 'b> {
                 self.stack.push(JitValue::Tuple(elements));
                 Ok(())
             }
-            Instruction::CallFunctionPositional { nargs } => {
+            Instruction::Call { nargs } => {
                 let nargs = nargs.get(arg);
 
                 let mut args = Vec::new();
@@ -489,7 +489,7 @@ impl<'a, 'b> FunctionCompiler<'a, 'b> {
                     _ => Err(JitCompileError::NotSupported),
                 }
             }
-            Instruction::CompareOperation { op, .. } => {
+            Instruction::CompareOp { op, .. } => {
                 let op = op.get(arg);
                 // the rhs is popped off first
                 let b = self.stack.pop().ok_or(JitCompileError::BadBytecode)?;

From 6df35bfce6dca3e5c0a75f9edc40a5b6125e98b0 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Wed, 7 Jan 2026 10:56:50 +0200
Subject: [PATCH 11/18] Fix more jit

---
 crates/jit/tests/common.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/jit/tests/common.rs b/crates/jit/tests/common.rs
index 17c280ec3c9..eabf27471b9 100644
--- a/crates/jit/tests/common.rs
+++ b/crates/jit/tests/common.rs
@@ -96,10 +96,10 @@ impl StackMachine {
                 let idx = idx.get(arg);
                 self.stack.push(constants[idx as usize].clone().into())
             }
-            Instruction::LoadNameAny(idx) => self
+            Instruction::LoadName(idx) => self
                 .stack
                 .push(StackValue::String(names[idx.get(arg) as usize].clone())),
-            Instruction::StoreLocal(idx) => {
+            Instruction::StoreName(idx) => {
                 let idx = idx.get(arg);
                 self.locals
                     .insert(names[idx as usize].clone(), self.stack.pop().unwrap());

From b222c8067640c580ddb0db7e79611b56eac35e0b Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 11:31:25 +0200
Subject: [PATCH 12/18] VarArgs -> Varargs

---
 crates/codegen/src/compile.rs        | 20 ++++++++++----------
 crates/compiler-core/src/bytecode.rs |  8 ++++----
 crates/vm/src/frame.rs               |  4 ++--
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/crates/codegen/src/compile.rs b/crates/codegen/src/compile.rs
index 815b216a074..f61b01a43ec 100644
--- a/crates/codegen/src/compile.rs
+++ b/crates/codegen/src/compile.rs
@@ -1815,7 +1815,7 @@ impl Compiler {
                     None => bytecode::RaiseKind::BareRaise,
                 };
                 self.set_source_range(*range);
-                emit!(self, Instruction::RaiseVarArgs { kind });
+                emit!(self, Instruction::RaiseVarargs { kind });
             }
             Stmt::Try(StmtTry {
                 body,
@@ -1886,7 +1886,7 @@ impl Compiler {
                     }
                     emit!(
                         self,
-                        Instruction::RaiseVarArgs {
+                        Instruction::RaiseVarargs {
                             kind: bytecode::RaiseKind::Raise,
                         }
                     );
@@ -2379,7 +2379,7 @@ impl Compiler {
                 // which then properly restores prev_exc before going to outer handler
                 emit!(
                     self,
-                    Instruction::RaiseVarArgs {
+                    Instruction::RaiseVarargs {
                         kind: bytecode::RaiseKind::ReraiseFromStack
                     }
                 );
@@ -2394,7 +2394,7 @@ impl Compiler {
                 emit!(self, Instruction::PopExcept);
                 emit!(
                     self,
-                    Instruction::RaiseVarArgs {
+                    Instruction::RaiseVarargs {
                         kind: bytecode::RaiseKind::ReraiseFromStack
                     }
                 );
@@ -2524,7 +2524,7 @@ impl Compiler {
                 // which does COPY 3; POP_EXCEPT; RERAISE
                 emit!(
                     self,
-                    Instruction::RaiseVarArgs {
+                    Instruction::RaiseVarargs {
                         kind: bytecode::RaiseKind::ReraiseFromStack,
                     }
                 );
@@ -2577,7 +2577,7 @@ impl Compiler {
         // NOTE: We emit RERAISE 0 BEFORE popping fblock so it is within cleanup handler scope
         emit!(
             self,
-            Instruction::RaiseVarArgs {
+            Instruction::RaiseVarargs {
                 kind: bytecode::RaiseKind::ReraiseFromStack,
             }
         );
@@ -2596,7 +2596,7 @@ impl Compiler {
         emit!(self, Instruction::PopExcept);
         emit!(
             self,
-            Instruction::RaiseVarArgs {
+            Instruction::RaiseVarargs {
                 kind: bytecode::RaiseKind::ReraiseFromStack,
             }
         );
@@ -2671,7 +2671,7 @@ impl Compiler {
             // Stack: [lasti, prev_exc, exc] - exception is on top
             emit!(
                 self,
-                Instruction::RaiseVarArgs {
+                Instruction::RaiseVarargs {
                     kind: bytecode::RaiseKind::ReraiseFromStack,
                 }
             );
@@ -2693,7 +2693,7 @@ impl Compiler {
             // RERAISE 1: reraise with lasti from stack
             emit!(
                 self,
-                Instruction::RaiseVarArgs {
+                Instruction::RaiseVarargs {
                     kind: bytecode::RaiseKind::ReraiseFromStack,
                 }
             );
@@ -6622,7 +6622,7 @@ impl Compiler {
             // Re-raise the exception
             emit!(
                 self,
-                Instruction::RaiseVarArgs {
+                Instruction::RaiseVarargs {
                     kind: bytecode::RaiseKind::ReraiseFromStack
                 }
             );
diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index c5f0708eb0a..3896e74dd9d 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -803,7 +803,7 @@ pub enum Instruction {
     PopJumpIfTrue {
         target: Arg<Label>,
     } = 100,
-    RaiseVarArgs {
+    RaiseVarargs {
         kind: Arg<RaiseKind>,
     } = 101,
     Reraise {
@@ -1684,7 +1684,7 @@ impl Instruction {
                 | Break { .. }
                 | ReturnValue
                 | ReturnConst { .. }
-                | RaiseVarArgs { .. }
+                | RaiseVarargs { .. }
                 | Reraise { .. }
         )
     }
@@ -1786,7 +1786,7 @@ impl Instruction {
             BeforeWith => 1, // push __exit__, then replace ctx_mgr with __enter__ result
             WithExceptStart => 1, // push __exit__ result
             PopBlock => 0,
-            RaiseVarArgs { kind } => {
+            RaiseVarargs { kind } => {
                 // Stack effects for different raise kinds:
                 // - Reraise (0): gets from VM state, no stack pop
                 // - Raise (1): pops 1 exception
@@ -2002,7 +2002,7 @@ impl Instruction {
             PopJumpIfTrue { target } => w!(POP_JUMP_IF_TRUE, target),
             PopTop => w!(POP_TOP),
             PushExcInfo => w!(PUSH_EXC_INFO),
-            RaiseVarArgs { kind } => w!(RAISE_VARARGS, ?kind),
+            RaiseVarargs { kind } => w!(RAISE_VARARGS, ?kind),
             Reraise { depth } => w!(RERAISE, depth),
             Resume { arg } => w!(RESUME, arg),
             ReturnConst { idx } => fmt_const("RETURN_CONST", arg, f, idx),
diff --git a/crates/vm/src/frame.rs b/crates/vm/src/frame.rs
index 105a9fa36a7..f4458e7142e 100644
--- a/crates/vm/src/frame.rs
+++ b/crates/vm/src/frame.rs
@@ -391,7 +391,7 @@ impl ExecutingFrame<'_> {
                     // Instruction::Reraise are reraise operations that should not add
                     // new traceback entries
                     let is_reraise = match op {
-                        bytecode::Instruction::RaiseVarArgs { kind } => matches!(
+                        bytecode::Instruction::RaiseVarargs { kind } => matches!(
                             kind.get(arg),
                             bytecode::RaiseKind::BareRaise | bytecode::RaiseKind::ReraiseFromStack
                         ),
@@ -1457,7 +1457,7 @@ impl ExecutingFrame<'_> {
                 self.pop_value();
                 Ok(None)
             }
-            bytecode::Instruction::RaiseVarArgs { kind } => self.execute_raise(vm, kind.get(arg)),
+            bytecode::Instruction::RaiseVarargs { kind } => self.execute_raise(vm, kind.get(arg)),
             bytecode::Instruction::Resume { arg: resume_arg } => {
                 // Resume execution after yield, await, or at function start
                 // In CPython, this checks instrumentation and eval breaker

From 00067003a3b24b0e694a62d6027b6a8ebf003716 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 13:05:30 +0200
Subject: [PATCH 13/18] Refactor scripts/generate_opcode_metadata.py

---
 Lib/_opcode_metadata.py             |  74 ++------
 scripts/generate_opcode_metadata.py | 271 ++++++----------------------
 2 files changed, 71 insertions(+), 274 deletions(-)

diff --git a/Lib/_opcode_metadata.py b/Lib/_opcode_metadata.py
index 0d6b7f1109e..c91b13c6421 100644
--- a/Lib/_opcode_metadata.py
+++ b/Lib/_opcode_metadata.py
@@ -7,32 +7,24 @@
 _specialized_opmap = {}
 
 opmap = {
-    'CACHE': 0,
     'BEFORE_ASYNC_WITH': 1,
     'BEFORE_WITH': 2,
-    'RESERVED_3': 3,
-    'BINARY_SLICE': 4,
     'BINARY_SUBSCR': 5,
     'CHECK_EG_MATCH': 6,
     'CHECK_EXC_MATCH': 7,
     'CLEANUP_THROW': 8,
     'DELETE_SUBSCR': 9,
     'END_ASYNC_FOR': 10,
-    'END_FOR': 11,
     'END_SEND': 12,
-    'EXIT_INIT_CHECK': 13,
     'FORMAT_SIMPLE': 14,
     'FORMAT_WITH_SPEC': 15,
     'GET_AITER': 16,
-    'RESERVED_17': 17,
+    'RESERVED': 17,
     'GET_ANEXT': 18,
     'GET_ITER': 19,
     'GET_LEN': 20,
     'GET_YIELD_FROM_ITER': 21,
-    'INTERPRETER_EXIT': 22,
-    'LOAD_ASSERTION_ERROR': 23,
     'LOAD_BUILD_CLASS': 24,
-    'LOAD_LOCALS': 25,
     'MAKE_FUNCTION': 26,
     'MATCH_KEYS': 27,
     'MATCH_MAPPING': 28,
@@ -41,11 +33,8 @@
     'POP_EXCEPT': 31,
     'POP_TOP': 32,
     'PUSH_EXC_INFO': 33,
-    'PUSH_NULL': 34,
-    'RETURN_GENERATOR': 35,
     'RETURN_VALUE': 36,
     'SETUP_ANNOTATIONS': 37,
-    'STORE_SLICE': 38,
     'STORE_SUBSCR': 39,
     'TO_BOOL': 40,
     'UNARY_INVERT': 41,
@@ -53,7 +42,6 @@
     'UNARY_NOT': 43,
     'WITH_EXCEPT_START': 44,
     'BINARY_OP': 45,
-    'BUILD_CONST_KEY_MAP': 46,
     'BUILD_LIST': 47,
     'BUILD_MAP': 48,
     'BUILD_SET': 49,
@@ -69,44 +57,29 @@
     'CONTAINS_OP': 59,
     'CONVERT_VALUE': 60,
     'COPY': 61,
-    'COPY_FREE_VARS': 62,
     'DELETE_ATTR': 63,
     'DELETE_DEREF': 64,
     'DELETE_FAST': 65,
     'DELETE_GLOBAL': 66,
     'DELETE_NAME': 67,
-    'DICT_MERGE': 68,
     'DICT_UPDATE': 69,
-    'ENTER_EXECUTOR': 70,
     'EXTENDED_ARG': 71,
     'FOR_ITER': 72,
     'GET_AWAITABLE': 73,
     'IMPORT_FROM': 74,
     'IMPORT_NAME': 75,
     'IS_OP': 76,
-    'JUMP_BACKWARD': 77,
-    'JUMP_BACKWARD_NO_INTERRUPT': 78,
-    'JUMP_FORWARD': 79,
     'LIST_APPEND': 80,
-    'LIST_EXTEND': 81,
     'LOAD_ATTR': 82,
     'LOAD_CONST': 83,
     'LOAD_DEREF': 84,
     'LOAD_FAST': 85,
     'LOAD_FAST_AND_CLEAR': 86,
-    'LOAD_FAST_CHECK': 87,
-    'LOAD_FAST_LOAD_FAST': 88,
-    'LOAD_FROM_DICT_OR_DEREF': 89,
-    'LOAD_FROM_DICT_OR_GLOBALS': 90,
     'LOAD_GLOBAL': 91,
     'LOAD_NAME': 92,
-    'LOAD_SUPER_ATTR': 93,
-    'MAKE_CELL': 94,
     'MAP_ADD': 95,
     'MATCH_CLASS': 96,
     'POP_JUMP_IF_FALSE': 97,
-    'POP_JUMP_IF_NONE': 98,
-    'POP_JUMP_IF_NOT_NONE': 99,
     'POP_JUMP_IF_TRUE': 100,
     'RAISE_VARARGS': 101,
     'RERAISE': 102,
@@ -114,12 +87,10 @@
     'SEND': 104,
     'SET_ADD': 105,
     'SET_FUNCTION_ATTRIBUTE': 106,
-    'SET_UPDATE': 107,
     'STORE_ATTR': 108,
     'STORE_DEREF': 109,
     'STORE_FAST': 110,
     'STORE_FAST_LOAD_FAST': 111,
-    'STORE_FAST_STORE_FAST': 112,
     'STORE_GLOBAL': 113,
     'STORE_NAME': 114,
     'SWAP': 115,
@@ -127,36 +98,27 @@
     'UNPACK_SEQUENCE': 117,
     'YIELD_VALUE': 118,
     'BREAK': 119,
-    'BUILD_LIST_UNPACK': 120,
+    'BUILD_LIST_FROM_TUPLES': 120,
     'BUILD_MAP_FOR_CALL': 121,
-    'BUILD_SET_UNPACK': 122,
-    'BUILD_TUPLE_ITER': 123,
-    'BUILD_TUPLE_UNPACK': 124,
-    'CALL_METHOD': 125,
-    'CALL_METHOD_KW': 126,
+    'BUILD_SET_FROM_TUPLES': 122,
+    'BUILD_TUPLE_FROM_ITER': 123,
+    'BUILD_TUPLE_FROM_TUPLES': 124,
+    'CALL_METHOD_POSITIONAL': 125,
+    'CALL_METHOD_KEYWORD': 126,
     'CALL_METHOD_EX': 127,
     'CONTINUE': 128,
-    'JUMP': 129,
-    'JUMP_IF_FALSE_OR_POP': 130,
-    'JUMP_IF_TRUE_OR_POP': 131,
-    'JUMP_IF_NOT_EXC_MATCH': 132,
-    'LOAD_CLASSDEREF': 133,
-    'LOAD_CLOSURE': 134,
-    'LOAD_METHOD': 135,
-    'POP_BLOCK': 136,
-    'REVERSE': 137,
-    'SET_EXC_INFO': 138,
-    'SUBSCRIPT': 139,
-    'UNARY_OP': 140,
-    'RESERVED_141': 141,
-    'RESERVED_142': 142,
-    'RESERVED_143': 143,
-    'RESERVED_144': 144,
-    'RESERVED_145': 145,
-    'RESERVED_146': 146,
-    'RESERVED_147': 147,
-    'RESERVED_148': 148,
+    'JUMP_IF_FALSE_OR_POP': 129,
+    'JUMP_IF_TRUE_OR_POP': 130,
+    'JUMP_IF_NOT_EXC_MATCH': 131,
+    'LOAD_CLASS_DEREF': 132,
+    'REVERSE': 133,
+    'SET_EXC_INFO': 134,
+    'SUBSCRIPT': 135,
     'RESUME': 149,
+    'JUMP': 252,
+    'LOAD_CLOSURE': 253,
+    'LOAD_METHOD': 254,
+    'POP_BLOCK': 255,
 }
 
 # CPython 3.13 compatible: opcodes < 44 have no argument
diff --git a/scripts/generate_opcode_metadata.py b/scripts/generate_opcode_metadata.py
index 9c440d52568..4ebdfd81776 100644
--- a/scripts/generate_opcode_metadata.py
+++ b/scripts/generate_opcode_metadata.py
@@ -1,208 +1,60 @@
-"""Generate _opcode_metadata.py for RustPython bytecode.
+"""
+Generate Lib/_opcode_metadata.py for RustPython bytecode.
 
 This file generates opcode metadata that is compatible with CPython 3.13.
-RustPython's Instruction enum is now ordered to match CPython opcode numbers exactly.
 """
 
+import itertools
+import pathlib
 import re
+import typing
+
+ROOT = pathlib.Path(__file__).parents[1]
+BYTECODE_FILE = ROOT / "crates" / "compiler-core" / "src" / "bytecode.rs"
+OPCODE_METADATA_FILE = ROOT / "Lib" / "_opcode_metadata.py"
+
+
+class Opcode(typing.NamedTuple):
+    rust_name: str
+    id: int
+
+    @property
+    def cpython_name(self) -> str:
+        if self.rust_name == "CopyItem":
+            return "COPY"
+        name = self.rust_name
+        name = re.sub(r"(?<=[a-z0-9])([A-Z])", r"_\1", name)
+        return re.sub(r"(\D)(\d+)$", r"\1_\2", name).upper()
+        return re.sub(r"(?<=[a-z0-9])([A-Z])", r"_\1", self.rust_name).upper()
+        return re.sub(r"(?<!^)(?=[A-Z])", "_", self.rust_name).upper()
+
+    @classmethod
+    def from_str(cls, body: str):
+        raw_variants = re.split(r"(\d+),", body.strip())
+        raw_variants.remove("")
+        for raw_name, raw_id in itertools.batched(raw_variants, 2):
+            name = re.findall(r"\b[A-Z][A-Za-z]*\d*\b(?=\s*[\({=])", raw_name)[0]
+            yield cls(rust_name=name.strip(), id=int(raw_id))
+
+    def __lt__(self, other: typing.Self) -> bool:
+        return self.id < other.id
+
+
+def extract_enum_body(contents: str) -> str:
+    res = re.search(r"pub enum Instruction \{(.+?)\n\}", contents, re.DOTALL)
+    if not res:
+        raise ValueError("Could not find Instruction enum")
+
+    return "\n".join(
+        line.split("//")[0].strip()  # Remove any comment. i.e. "foo // some comment"
+        for line in res.group(1).splitlines()
+        if not line.strip().startswith("//")  # Ignore comment lines
+    )
 
-# Read the bytecode.rs file to get instruction names
-with open("crates/compiler-core/src/bytecode.rs", "r") as f:
-    content = f.read()
-
-# Find the Instruction enum
-match = re.search(r"pub enum Instruction \{(.+?)\n\}", content, re.DOTALL)
-if not match:
-    raise ValueError("Could not find Instruction enum")
-
-enum_body = match.group(1)
-
-# Extract variant names
-variants = []
-for line in enum_body.split("\n"):
-    if line.strip().startswith("///") or line.strip().startswith("//"):
-        continue
-    m = re.match(r"^\s+([A-Z][a-zA-Z0-9]*)", line)
-    if m:
-        variants.append(m.group(1))
-
-print(f"Found {len(variants)} instruction variants")
-
-# Map RustPython variant names to CPython-compatible names
-# The opcode number is the index in the Instruction enum
-name_mapping = {
-    # Dummy/placeholder instructions
-    "Cache": "CACHE",
-    "Reserved3": "RESERVED",
-    "Reserved17": "RESERVED",
-    "Reserved141": "RESERVED",
-    "Reserved142": "RESERVED",
-    "Reserved143": "RESERVED",
-    "Reserved144": "RESERVED",
-    "Reserved145": "RESERVED",
-    "Reserved146": "RESERVED",
-    "Reserved147": "RESERVED",
-    "Reserved148": "RESERVED",
-    "BinarySlice": "BINARY_SLICE",
-    "EndFor": "END_FOR",
-    "ExitInitCheck": "EXIT_INIT_CHECK",
-    "GetYieldFromIter": "GET_YIELD_FROM_ITER",
-    "InterpreterExit": "INTERPRETER_EXIT",
-    "LoadAssertionError": "LOAD_ASSERTION_ERROR",
-    "LoadLocals": "LOAD_LOCALS",
-    "PushNull": "PUSH_NULL",
-    "ReturnGenerator": "RETURN_GENERATOR",
-    "StoreSlice": "STORE_SLICE",
-    "UnaryInvert": "UNARY_INVERT",
-    "UnaryNegative": "UNARY_NEGATIVE",
-    "UnaryNot": "UNARY_NOT",
-    "BuildConstKeyMap": "BUILD_CONST_KEY_MAP",
-    "CopyFreeVars": "COPY_FREE_VARS",
-    "DictMerge": "DICT_MERGE",
-    "EnterExecutor": "ENTER_EXECUTOR",
-    "JumpBackward": "JUMP_BACKWARD",
-    "JumpBackwardNoInterrupt": "JUMP_BACKWARD_NO_INTERRUPT",
-    "JumpForward": "JUMP_FORWARD",
-    "ListExtend": "LIST_EXTEND",
-    "LoadFastCheck": "LOAD_FAST_CHECK",
-    "LoadFastLoadFast": "LOAD_FAST_LOAD_FAST",
-    "LoadFromDictOrDeref": "LOAD_FROM_DICT_OR_DEREF",
-    "LoadFromDictOrGlobals": "LOAD_FROM_DICT_OR_GLOBALS",
-    "LoadSuperAttr": "LOAD_SUPER_ATTR",
-    "MakeCell": "MAKE_CELL",
-    "PopJumpIfNone": "POP_JUMP_IF_NONE",
-    "PopJumpIfNotNone": "POP_JUMP_IF_NOT_NONE",
-    "SetUpdate": "SET_UPDATE",
-    "StoreFastStoreFast": "STORE_FAST_STORE_FAST",
-    # Real instructions
-    "BeforeAsyncWith": "BEFORE_ASYNC_WITH",
-    "BeforeWith": "BEFORE_WITH",
-    "BinaryOp": "BINARY_OP",
-    "BinarySubscript": "BINARY_SUBSCR",
-    "Break": "BREAK",
-    "BuildList": "BUILD_LIST",
-    "BuildListFromTuples": "BUILD_LIST_UNPACK",
-    "BuildMap": "BUILD_MAP",
-    "BuildMapForCall": "BUILD_MAP_FOR_CALL",
-    "BuildSet": "BUILD_SET",
-    "BuildSetFromTuples": "BUILD_SET_UNPACK",
-    "BuildSlice": "BUILD_SLICE",
-    "BuildString": "BUILD_STRING",
-    "BuildTuple": "BUILD_TUPLE",
-    "BuildTupleFromIter": "BUILD_TUPLE_ITER",
-    "BuildTupleFromTuples": "BUILD_TUPLE_UNPACK",
-    "CallFunctionEx": "CALL_FUNCTION_EX",
-    "CallFunctionKeyword": "CALL_KW",
-    "CallFunctionPositional": "CALL",
-    "CallIntrinsic1": "CALL_INTRINSIC_1",
-    "CallIntrinsic2": "CALL_INTRINSIC_2",
-    "CallMethodEx": "CALL_METHOD_EX",
-    "CallMethodKeyword": "CALL_METHOD_KW",
-    "CallMethodPositional": "CALL_METHOD",
-    "CheckEgMatch": "CHECK_EG_MATCH",
-    "CheckExcMatch": "CHECK_EXC_MATCH",
-    "CleanupThrow": "CLEANUP_THROW",
-    "CompareOperation": "COMPARE_OP",
-    "ContainsOp": "CONTAINS_OP",
-    "Continue": "CONTINUE",
-    "ConvertValue": "CONVERT_VALUE",
-    "CopyItem": "COPY",
-    "DeleteAttr": "DELETE_ATTR",
-    "DeleteDeref": "DELETE_DEREF",
-    "DeleteFast": "DELETE_FAST",
-    "DeleteGlobal": "DELETE_GLOBAL",
-    "DeleteLocal": "DELETE_NAME",
-    "DeleteSubscript": "DELETE_SUBSCR",
-    "DictUpdate": "DICT_UPDATE",
-    "EndAsyncFor": "END_ASYNC_FOR",
-    "EndSend": "END_SEND",
-    "ExtendedArg": "EXTENDED_ARG",
-    "ForIter": "FOR_ITER",
-    "FormatSimple": "FORMAT_SIMPLE",
-    "FormatWithSpec": "FORMAT_WITH_SPEC",
-    "GetAIter": "GET_AITER",
-    "GetANext": "GET_ANEXT",
-    "GetAwaitable": "GET_AWAITABLE",
-    "GetIter": "GET_ITER",
-    "GetLen": "GET_LEN",
-    "ImportFrom": "IMPORT_FROM",
-    "ImportName": "IMPORT_NAME",
-    "IsOp": "IS_OP",
-    "Jump": "JUMP",
-    "JumpIfFalseOrPop": "JUMP_IF_FALSE_OR_POP",
-    "JumpIfNotExcMatch": "JUMP_IF_NOT_EXC_MATCH",
-    "JumpIfTrueOrPop": "JUMP_IF_TRUE_OR_POP",
-    "ListAppend": "LIST_APPEND",
-    "LoadAttr": "LOAD_ATTR",
-    "LoadBuildClass": "LOAD_BUILD_CLASS",
-    "LoadClassDeref": "LOAD_CLASSDEREF",
-    "LoadClosure": "LOAD_CLOSURE",
-    "LoadConst": "LOAD_CONST",
-    "LoadDeref": "LOAD_DEREF",
-    "LoadFast": "LOAD_FAST",
-    "LoadFastAndClear": "LOAD_FAST_AND_CLEAR",
-    "LoadGlobal": "LOAD_GLOBAL",
-    "LoadMethod": "LOAD_METHOD",
-    "LoadNameAny": "LOAD_NAME",
-    "MakeFunction": "MAKE_FUNCTION",
-    "MapAdd": "MAP_ADD",
-    "MatchClass": "MATCH_CLASS",
-    "MatchKeys": "MATCH_KEYS",
-    "MatchMapping": "MATCH_MAPPING",
-    "MatchSequence": "MATCH_SEQUENCE",
-    "Nop": "NOP",
-    "PopBlock": "POP_BLOCK",
-    "PopException": "POP_EXCEPT",
-    "PopJumpIfFalse": "POP_JUMP_IF_FALSE",
-    "PopJumpIfTrue": "POP_JUMP_IF_TRUE",
-    "PopTop": "POP_TOP",
-    "PushExcInfo": "PUSH_EXC_INFO",
-    "Raise": "RAISE_VARARGS",
-    "Reraise": "RERAISE",
-    "Resume": "RESUME",
-    "ReturnConst": "RETURN_CONST",
-    "ReturnValue": "RETURN_VALUE",
-    "Reverse": "REVERSE",
-    "Send": "SEND",
-    "SetAdd": "SET_ADD",
-    "SetExcInfo": "SET_EXC_INFO",
-    "SetFunctionAttribute": "SET_FUNCTION_ATTRIBUTE",
-    "SetupAnnotation": "SETUP_ANNOTATIONS",
-    "StoreAttr": "STORE_ATTR",
-    "StoreDeref": "STORE_DEREF",
-    "StoreFast": "STORE_FAST",
-    "StoreFastLoadFast": "STORE_FAST_LOAD_FAST",
-    "StoreGlobal": "STORE_GLOBAL",
-    "StoreLocal": "STORE_NAME",
-    "StoreSubscript": "STORE_SUBSCR",
-    "Subscript": "SUBSCRIPT",
-    "Swap": "SWAP",
-    "ToBool": "TO_BOOL",
-    "UnaryOperation": "UNARY_OP",
-    "UnpackEx": "UNPACK_EX",
-    "UnpackSequence": "UNPACK_SEQUENCE",
-    "WithExceptStart": "WITH_EXCEPT_START",
-    "YieldValue": "YIELD_VALUE",
-}
-
-# Build opmap with RustPython instruction indices
-opmap = {}
-rust_to_cpython_name = {}
-for i, variant in enumerate(variants):
-    cpython_name = name_mapping.get(variant, variant.upper())
-    # Skip adding duplicates (RESERVED appears multiple times)
-    if cpython_name == "RESERVED":
-        # Use unique names for reserved slots
-        cpython_name = f"RESERVED_{i}"
-    if cpython_name not in opmap:
-        opmap[cpython_name] = i
-    rust_to_cpython_name[variant] = cpython_name
-
-
-# Find specific instruction indices for categorization
-def find_opcode(cpython_name):
-    return opmap.get(cpython_name, -1)
 
+contents = BYTECODE_FILE.read_text()
+enum_body = extract_enum_body(contents)
+opcodes = list(Opcode.from_str(enum_body))
 
 # Generate the output file
 output = """# This file is generated by scripts/generate_opcode_metadata.py
@@ -216,8 +68,8 @@ def find_opcode(cpython_name):
 opmap = {
 """
 
-for name, num in sorted(opmap.items(), key=lambda x: x[1]):
-    output += f"    '{name}': {num},\n"
+for opcode in sorted(opcodes):
+    output += f"    '{opcode.cpython_name}': {opcode.id},\n"
 
 output += """}
 
@@ -226,21 +78,4 @@ def find_opcode(cpython_name):
 MIN_INSTRUMENTED_OPCODE = 236
 """
 
-with open("Lib/_opcode_metadata.py", "w") as f:
-    f.write(output)
-
-print("Generated Lib/_opcode_metadata.py")
-print("\nKey opcode indices (matching CPython 3.13):")
-print(f"  CACHE = {find_opcode('CACHE')} (expected: 0)")
-print(f"  BEFORE_ASYNC_WITH = {find_opcode('BEFORE_ASYNC_WITH')} (expected: 1)")
-print(f"  BINARY_SUBSCR = {find_opcode('BINARY_SUBSCR')} (expected: 5)")
-print(
-    f"  WITH_EXCEPT_START = {find_opcode('WITH_EXCEPT_START')} (expected: 44, HAVE_ARGUMENT)"
-)
-print(f"  BINARY_OP = {find_opcode('BINARY_OP')} (expected: 45)")
-print(f"  LOAD_CONST = {find_opcode('LOAD_CONST')} (expected: 83)")
-print(f"  LOAD_FAST = {find_opcode('LOAD_FAST')} (expected: 85)")
-print(f"  LOAD_GLOBAL = {find_opcode('LOAD_GLOBAL')} (expected: 91)")
-print(f"  STORE_FAST = {find_opcode('STORE_FAST')} (expected: 110)")
-print(f"  YIELD_VALUE = {find_opcode('YIELD_VALUE')} (expected: 118)")
-print(f"  RESUME = {find_opcode('RESUME')} (expected: 149)")
+OPCODE_METADATA_FILE.write_text(output)

From 89c20f691a0492a11260b17872e3c5e62c5f5bf3 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 14:05:42 +0200
Subject: [PATCH 14/18] Add placeholder opcodes

---
 Lib/_opcode_metadata.py              | 29 ++++++++
 crates/compiler-core/src/bytecode.rs | 98 +++++++++++++++++++++-------
 2 files changed, 103 insertions(+), 24 deletions(-)

diff --git a/Lib/_opcode_metadata.py b/Lib/_opcode_metadata.py
index c91b13c6421..529f5cbf656 100644
--- a/Lib/_opcode_metadata.py
+++ b/Lib/_opcode_metadata.py
@@ -7,15 +7,20 @@
 _specialized_opmap = {}
 
 opmap = {
+    'CACHE': 0,
     'BEFORE_ASYNC_WITH': 1,
     'BEFORE_WITH': 2,
+    'BINARY_OP_INPLACE_ADD_UNICODE': 3,
+    'BINARY_SLICE': 4,
     'BINARY_SUBSCR': 5,
     'CHECK_EG_MATCH': 6,
     'CHECK_EXC_MATCH': 7,
     'CLEANUP_THROW': 8,
     'DELETE_SUBSCR': 9,
     'END_ASYNC_FOR': 10,
+    'END_FOR': 11,
     'END_SEND': 12,
+    'EXIT_INIT_CHECK': 13,
     'FORMAT_SIMPLE': 14,
     'FORMAT_WITH_SPEC': 15,
     'GET_AITER': 16,
@@ -24,7 +29,10 @@
     'GET_ITER': 19,
     'GET_LEN': 20,
     'GET_YIELD_FROM_ITER': 21,
+    'INTERPRETER_EXIT': 22,
+    'LOAD_ASSERTION_ERROR': 23,
     'LOAD_BUILD_CLASS': 24,
+    'LOAD_LOCALS': 25,
     'MAKE_FUNCTION': 26,
     'MATCH_KEYS': 27,
     'MATCH_MAPPING': 28,
@@ -33,8 +41,11 @@
     'POP_EXCEPT': 31,
     'POP_TOP': 32,
     'PUSH_EXC_INFO': 33,
+    'PUSH_NULL': 34,
+    'RETURN_GENERATOR': 35,
     'RETURN_VALUE': 36,
     'SETUP_ANNOTATIONS': 37,
+    'STORE_SLICE': 38,
     'STORE_SUBSCR': 39,
     'TO_BOOL': 40,
     'UNARY_INVERT': 41,
@@ -42,6 +53,7 @@
     'UNARY_NOT': 43,
     'WITH_EXCEPT_START': 44,
     'BINARY_OP': 45,
+    'BUILD_CONST_KEY_MAP': 46,
     'BUILD_LIST': 47,
     'BUILD_MAP': 48,
     'BUILD_SET': 49,
@@ -57,29 +69,44 @@
     'CONTAINS_OP': 59,
     'CONVERT_VALUE': 60,
     'COPY': 61,
+    'COPY_FREE_VARS': 62,
     'DELETE_ATTR': 63,
     'DELETE_DEREF': 64,
     'DELETE_FAST': 65,
     'DELETE_GLOBAL': 66,
     'DELETE_NAME': 67,
+    'DICT_MERGE': 68,
     'DICT_UPDATE': 69,
+    'ENTER_EXECUTOR': 70,
     'EXTENDED_ARG': 71,
     'FOR_ITER': 72,
     'GET_AWAITABLE': 73,
     'IMPORT_FROM': 74,
     'IMPORT_NAME': 75,
     'IS_OP': 76,
+    'JUMP_BACKWARD': 77,
+    'JUMP_BACKWARD_NO_INTERRUPT': 78,
+    'JUMP_FORWARD': 79,
     'LIST_APPEND': 80,
+    'LIST_EXTEND': 81,
     'LOAD_ATTR': 82,
     'LOAD_CONST': 83,
     'LOAD_DEREF': 84,
     'LOAD_FAST': 85,
     'LOAD_FAST_AND_CLEAR': 86,
+    'LOAD_FAST_CHECK': 87,
+    'LOAD_FAST_LOAD_FAST': 88,
+    'LOAD_FROM_DICT_OR_DEREF': 89,
+    'LOAD_FROM_DICT_OR_GLOBALS': 90,
     'LOAD_GLOBAL': 91,
     'LOAD_NAME': 92,
+    'LOAD_SUPER_ATTR': 93,
+    'MAKE_CELL': 94,
     'MAP_ADD': 95,
     'MATCH_CLASS': 96,
     'POP_JUMP_IF_FALSE': 97,
+    'POP_JUMP_IF_NONE': 98,
+    'POP_JUMP_IF_NOT_NONE': 99,
     'POP_JUMP_IF_TRUE': 100,
     'RAISE_VARARGS': 101,
     'RERAISE': 102,
@@ -87,10 +114,12 @@
     'SEND': 104,
     'SET_ADD': 105,
     'SET_FUNCTION_ATTRIBUTE': 106,
+    'SET_UPDATE': 107,
     'STORE_ATTR': 108,
     'STORE_DEREF': 109,
     'STORE_FAST': 110,
     'STORE_FAST_LOAD_FAST': 111,
+    'STORE_FAST_STORE_FAST': 112,
     'STORE_GLOBAL': 113,
     'STORE_NAME': 114,
     'SWAP': 115,
diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index 3896e74dd9d..d16027fbde2 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -676,15 +676,20 @@ pub type NameIdx = u32;
 #[repr(u8)]
 pub enum Instruction {
     // ==================== No-argument instructions (opcode < 44) ====================
+    Cache = 0, // Placeholder
     BeforeAsyncWith = 1,
     BeforeWith = 2,
+    BinaryOpInplaceAddUnicode = 3, // Placeholder
+    BinarySlice = 4,               // Placeholder
     BinarySubscr = 5,
     CheckEgMatch = 6,
     CheckExcMatch = 7,
     CleanupThrow = 8,
     DeleteSubscr = 9,
     EndAsyncFor = 10,
+    EndFor = 11, // Placeholder
     EndSend = 12,
+    ExitInitCheck = 13, // Placeholder
     FormatSimple = 14,
     FormatWithSpec = 15,
     GetAIter = 16,
@@ -693,7 +698,10 @@ pub enum Instruction {
     GetIter = 19,
     GetLen = 20,
     GetYieldFromIter = 21,
+    InterpreterExit = 22,    // Placeholder
+    LoadAssertionError = 23, // Placeholder
     LoadBuildClass = 24,
+    LoadLocals = 25, // Placeholder
     MakeFunction = 26,
     MatchKeys = 27,
     MatchMapping = 28,
@@ -702,8 +710,11 @@ pub enum Instruction {
     PopExcept = 31,
     PopTop = 32,
     PushExcInfo = 33,
+    PushNull = 34,        // Placeholder
+    ReturnGenerator = 35, // Placeholder
     ReturnValue = 36,
     SetupAnnotations = 37,
+    StoreSlice = 38, // Placeholder
     StoreSubscr = 39,
     ToBool = 40,
     UnaryInvert = 41,
@@ -714,6 +725,9 @@ pub enum Instruction {
     BinaryOp {
         op: Arg<BinaryOperator>,
     } = 45,
+    BuildConstKeyMap {
+        size: Arg<u32>,
+    } = 46, // Placeholder
     BuildList {
         size: Arg<u32>,
     } = 47,
@@ -757,6 +771,9 @@ pub enum Instruction {
     CopyItem {
         index: Arg<u32>,
     } = 61,
+    CopyFreeVars {
+        count: Arg<u32>,
+    } = 62, // Placeholder
     DeleteAttr {
         idx: Arg<NameIdx>,
     } = 63,
@@ -764,9 +781,13 @@ pub enum Instruction {
     DeleteFast(Arg<NameIdx>) = 65,
     DeleteGlobal(Arg<NameIdx>) = 66,
     DeleteName(Arg<NameIdx>) = 67,
+    DictMerge {
+        index: Arg<u32>,
+    } = 68, // Placeholder
     DictUpdate {
         index: Arg<u32>,
     } = 69,
+    EnterExecutor = 70, // Placeholder
     ExtendedArg = 71,
     ForIter {
         target: Arg<Label>,
@@ -779,9 +800,21 @@ pub enum Instruction {
         idx: Arg<NameIdx>,
     } = 75,
     IsOp(Arg<Invert>) = 76,
+    JumpBackward {
+        target: Arg<Label>,
+    } = 77, // Placeholder
+    JumpBackwardNoInterrupt {
+        target: Arg<Label>,
+    } = 78, // Placeholder
+    JumpForward {
+        target: Arg<Label>,
+    } = 79, // Placeholder
     ListAppend {
         i: Arg<u32>,
     } = 80,
+    ListExtend {
+        i: Arg<u32>,
+    } = 81, // Placeholder
     LoadAttr {
         idx: Arg<NameIdx>,
     } = 82,
@@ -791,8 +824,18 @@ pub enum Instruction {
     LoadDeref(Arg<NameIdx>) = 84,
     LoadFast(Arg<NameIdx>) = 85,
     LoadFastAndClear(Arg<NameIdx>) = 86,
+    LoadFastCheck(Arg<NameIdx>) = 87, // Placeholder
+    LoadFastLoadFast {
+        arg: Arg<u32>,
+    } = 88, // Placeholder
+    LoadFromDictOrDeref(Arg<NameIdx>) = 89, // Placeholder
+    LoadFromDictOrGlobals(Arg<NameIdx>) = 90, // Placeholder
     LoadGlobal(Arg<NameIdx>) = 91,
     LoadName(Arg<NameIdx>) = 92,
+    LoadSuperAttr {
+        arg: Arg<u32>,
+    } = 93, // Placeholder
+    MakeCell(Arg<NameIdx>) = 94, // Placeholder
     MapAdd {
         i: Arg<u32>,
     } = 95,
@@ -800,6 +843,12 @@ pub enum Instruction {
     PopJumpIfFalse {
         target: Arg<Label>,
     } = 97,
+    PopJumpIfNone {
+        target: Arg<Label>,
+    } = 98, // Placeholder
+    PopJumpIfNotNone {
+        target: Arg<Label>,
+    } = 99, // Placeholder
     PopJumpIfTrue {
         target: Arg<Label>,
     } = 100,
@@ -821,6 +870,9 @@ pub enum Instruction {
     SetFunctionAttribute {
         attr: Arg<MakeFunctionFlags>,
     } = 106,
+    SetUpdate {
+        i: Arg<u32>,
+    } = 107, // Placeholder
     StoreAttr {
         idx: Arg<NameIdx>,
     } = 108,
@@ -830,6 +882,9 @@ pub enum Instruction {
         store_idx: Arg<NameIdx>,
         load_idx: Arg<NameIdx>,
     } = 111,
+    StoreFastStoreFast {
+        arg: Arg<u32>,
+    } = 112, // Placeholder
     StoreGlobal(Arg<NameIdx>) = 113,
     StoreName(Arg<NameIdx>) = 114,
     Swap {
@@ -909,31 +964,26 @@ impl TryFrom<u8> for Instruction {
 
     #[inline]
     fn try_from(value: u8) -> Result<Self, MarshalError> {
+        let cpython_start = Instruction::Cache as u8;
+        let cpython_end = Instruction::YieldValue as u8;
+
+        let resume_id = Instruction::Resume { arg: Arg::marker() } as u8;
+
+        let custom_start = Instruction::Break {
+            target: Arg::marker(),
+        } as u8;
+        let custom_end = Instruction::Subscript as u8;
+
+        let pseudo_start = Instruction::Jump {
+            target: Arg::marker(),
+        } as u8;
+        let pseudo_end = Instruction::PopBlock as u8;
+
         match value {
-            1
-            | 2
-            | 5..=10
-            | 12
-            | 14..=21
-            | 24
-            | 26..=33
-            | 36
-            | 37
-            | 39..=45
-            | 47..=61
-            | 63..=67
-            | 69
-            | 71..=76
-            | 80
-            | 82..=86
-            | 91
-            | 92
-            | 95..=97
-            | 100..=106
-            | 108..=111
-            | 113..=135
-            | 149
-            | 252..=255 => Ok(unsafe { core::mem::transmute::<u8, Self>(value) }),
+            cpython_start..=cpython_end
+            | resume_id
+            | custom_start..=custom_end
+            | pseudo_start..=pseudo_end => Ok(unsafe { core::mem::transmute::<u8, Self>(value) }),
             _ => Err(Self::Error::InvalidBytecode),
         }
     }

From 6cdf6f50e2f29fadccf487d076bb85dcdbd2e411 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 14:23:57 +0200
Subject: [PATCH 15/18] Fix

---
 crates/compiler-core/src/bytecode.rs | 44 ++++++++++++++++++----------
 crates/vm/src/frame.rs               |  2 +-
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index d16027fbde2..6ac8d48067d 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -959,32 +959,42 @@ pub enum Instruction {
 
 const _: () = assert!(mem::size_of::<Instruction>() == 1);
 
+impl From<Instruction> for u8 {
+    #[inline]
+    fn from(ins: Instruction) -> Self {
+        // SAFETY: there's no padding bits
+        unsafe { core::mem::transmute::<Instruction, Self>(ins) }
+    }
+}
+
 impl TryFrom<u8> for Instruction {
     type Error = MarshalError;
 
     #[inline]
     fn try_from(value: u8) -> Result<Self, MarshalError> {
-        let cpython_start = Instruction::Cache as u8;
-        let cpython_end = Instruction::YieldValue as u8;
+        let cpython_start = u8::from(Self::Cache);
+        let cpython_end = u8::from(Self::YieldValue { arg: Arg::marker() });
 
-        let resume_id = Instruction::Resume { arg: Arg::marker() } as u8;
+        let resume_id = u8::from(Self::Resume { arg: Arg::marker() });
 
-        let custom_start = Instruction::Break {
+        let custom_start = u8::from(Self::Break {
             target: Arg::marker(),
-        } as u8;
-        let custom_end = Instruction::Subscript as u8;
+        });
+        let custom_end = u8::from(Self::Subscript);
 
-        let pseudo_start = Instruction::Jump {
+        let pseudo_start = u8::from(Self::Jump {
             target: Arg::marker(),
-        } as u8;
-        let pseudo_end = Instruction::PopBlock as u8;
-
-        match value {
-            cpython_start..=cpython_end
-            | resume_id
-            | custom_start..=custom_end
-            | pseudo_start..=pseudo_end => Ok(unsafe { core::mem::transmute::<u8, Self>(value) }),
-            _ => Err(Self::Error::InvalidBytecode),
+        });
+        let pseudo_end = u8::from(Self::PopBlock);
+
+        if (cpython_start..=cpython_end).contains(&value)
+            || value == resume_id
+            || (custom_start..=custom_end).contains(&value)
+            || (pseudo_start..=pseudo_end).contains(&value)
+        {
+            Ok(unsafe { core::mem::transmute::<u8, Self>(value) })
+        } else {
+            Err(Self::Error::InvalidBytecode)
         }
     }
 }
@@ -1899,6 +1909,7 @@ impl Instruction {
             UnaryNegative => 0,
             UnaryNot => 0,
             GetYieldFromIter => 0,
+            _ => unreachable!("Tried to get stack effect of a placeholder instruction ({self:?}"),
         }
     }
 
@@ -2087,6 +2098,7 @@ impl Instruction {
             UnaryNot => w!(UNARY_NOT),
             YieldValue { arg } => w!(YIELD_VALUE, arg),
             GetYieldFromIter => w!(GET_YIELD_FROM_ITER),
+            _ => w!(RUSTPYTHON_PLACEHOLDER),
         }
     }
 }
diff --git a/crates/vm/src/frame.rs b/crates/vm/src/frame.rs
index f4458e7142e..275269c5cbe 100644
--- a/crates/vm/src/frame.rs
+++ b/crates/vm/src/frame.rs
@@ -1779,7 +1779,7 @@ impl ExecutingFrame<'_> {
                 self.push_value(vm.ctx.new_bool(!value).into());
                 Ok(None)
             }
-            bytecode::Instruction::Reserved => {
+            _ => {
                 unreachable!("{instruction:?} instruction should not be executed")
             }
         }

From 8e1433cf986c6bcc50470e3f589b488306ebc40d Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 14:25:26 +0200
Subject: [PATCH 16/18] Don't crash on placejolder bytecode

---
 crates/compiler-core/src/bytecode.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
index 6ac8d48067d..19380be4713 100644
--- a/crates/compiler-core/src/bytecode.rs
+++ b/crates/compiler-core/src/bytecode.rs
@@ -1909,7 +1909,7 @@ impl Instruction {
             UnaryNegative => 0,
             UnaryNot => 0,
             GetYieldFromIter => 0,
-            _ => unreachable!("Tried to get stack effect of a placeholder instruction ({self:?}"),
+            _ => 0,
         }
     }
 

From 9e6cbedd396c14fa03339f5609601ad4e0fe1b5f Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 14:26:05 +0200
Subject: [PATCH 17/18] Unmark passing test

---
 Lib/test/test__opcode.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Lib/test/test__opcode.py b/Lib/test/test__opcode.py
index 949174a2739..dabe95f7167 100644
--- a/Lib/test/test__opcode.py
+++ b/Lib/test/test__opcode.py
@@ -58,7 +58,6 @@ def check_function(self, func, expected):
 
 
 class StackEffectTests(unittest.TestCase):
-    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: ValueError not raised by stack_effect
     def test_stack_effect(self):
         self.assertEqual(stack_effect(dis.opmap['POP_TOP']), -1)
         self.assertEqual(stack_effect(dis.opmap['BUILD_SLICE'], 0), -1)

From 258f61cc0064a11c76ec129ac1169c8cbc1ff3f6 Mon Sep 17 00:00:00 2001
From: ShaharNaveh <50263213+ShaharNaveh@users.noreply.github.com>
Date: Fri, 9 Jan 2026 14:34:25 +0200
Subject: [PATCH 18/18] Mark failing test

---
 Lib/test/test_dis.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lib/test/test_dis.py b/Lib/test/test_dis.py
index eddfc155619..9526bdcbbaa 100644
--- a/Lib/test/test_dis.py
+++ b/Lib/test/test_dis.py
@@ -937,6 +937,7 @@ def test_opname(self):
     def test_boundaries(self):
         self.assertEqual(dis.opmap["EXTENDED_ARG"], dis.EXTENDED_ARG)
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: 29 not less than or equal to 20
     def test_widths(self):
         long_opcodes = set(['JUMP_BACKWARD_NO_INTERRUPT',
                             'INSTRUMENTED_CALL_FUNCTION_EX'])