From 78a7dddc20634d987a9520854956f9f8e0290252 Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Tue, 20 Jan 2026 03:33:44 +0900
Subject: [PATCH 1/4] Align ForIter behavior (incomplete)

---
 crates/codegen/src/compile.rs                    | 5 +++++
 crates/compiler-core/src/bytecode/instruction.rs | 8 +++-----
 crates/vm/src/frame.rs                           | 8 +++-----
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/crates/codegen/src/compile.rs b/crates/codegen/src/compile.rs
index a72e425e290..c41c2584523 100644
--- a/crates/codegen/src/compile.rs
+++ b/crates/codegen/src/compile.rs
@@ -4929,6 +4929,9 @@ impl Compiler {
 
         if is_async {
             emit!(self, Instruction::EndAsyncFor);
+        } else {
+            // Pop the iterator after loop ends
+            emit!(self, Instruction::PopTop);
         }
         self.compile_statements(orelse)?;
 
@@ -7367,6 +7370,8 @@ impl Compiler {
             if is_async {
                 emit!(self, Instruction::EndAsyncFor);
                 emit!(self, Instruction::PopTop);
+            } else {
+                emit!(self, Instruction::PopTop);
             }
         }
 
diff --git a/crates/compiler-core/src/bytecode/instruction.rs b/crates/compiler-core/src/bytecode/instruction.rs
index 41f86dca39b..040e46a5d89 100644
--- a/crates/compiler-core/src/bytecode/instruction.rs
+++ b/crates/compiler-core/src/bytecode/instruction.rs
@@ -584,11 +584,9 @@ impl InstructionMetadata for Instruction {
             Self::FormatSimple => 0,
             Self::FormatWithSpec => -1,
             Self::ForIter { .. } => {
-                if jump {
-                    -1
-                } else {
-                    1
-                }
+                // jump=False: push next value (+1)
+                // jump=True: iterator stays on stack, no change (0)
+                if jump { 0 } else { 1 }
             }
             Self::IsOp(_) => -1,
             Self::ContainsOp(_) => -1,
diff --git a/crates/vm/src/frame.rs b/crates/vm/src/frame.rs
index ea9177a3d7c..f6faf6f49cb 100644
--- a/crates/vm/src/frame.rs
+++ b/crates/vm/src/frame.rs
@@ -2380,15 +2380,13 @@ impl ExecutingFrame<'_> {
                 Ok(None)
             }
             Ok(PyIterReturn::StopIteration(_)) => {
-                // Pop iterator from stack:
-                self.pop_value();
-
-                // End of for loop
+                // CPython 3.14: Do NOT pop iterator here
+                // POP_ITER instruction will handle cleanup after the loop
                 self.jump(target);
                 Ok(None)
             }
             Err(next_error) => {
-                // Pop iterator from stack:
+                // On error, pop iterator and propagate
                 self.pop_value();
                 Err(next_error)
             }

From d1f15f90883d6559eb9e8175885f2f490cabb911 Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Tue, 20 Jan 2026 10:53:47 +0900
Subject: [PATCH 2/4] Romove JUMP_IF_{TRUE,FALSE}_OR_POP, subscript

---
 Lib/_opcode_metadata.py                       |  3 --
 crates/codegen/src/compile.rs                 | 11 ++----
 .../compiler-core/src/bytecode/instruction.rs | 34 -------------------
 crates/stdlib/src/opcode.rs                   |  2 --
 crates/vm/src/frame.rs                        | 32 -----------------
 5 files changed, 3 insertions(+), 79 deletions(-)

diff --git a/Lib/_opcode_metadata.py b/Lib/_opcode_metadata.py
index 3345870e4ec..2b18ad4d652 100644
--- a/Lib/_opcode_metadata.py
+++ b/Lib/_opcode_metadata.py
@@ -218,13 +218,10 @@
     'BUILD_CONST_KEY_MAP': 215,
     'BREAK': 216,
     'CONTINUE': 217,
-    'JUMP_IF_FALSE_OR_POP': 218,
-    'JUMP_IF_TRUE_OR_POP': 219,
     'JUMP_IF_NOT_EXC_MATCH': 220,
     'LOAD_ASSERTION_ERROR': 221,
     'RETURN_CONST': 222,
     'SET_EXC_INFO': 223,
-    'SUBSCRIPT': 224,
     'INSTRUMENTED_END_FOR': 234,
     'INSTRUMENTED_POP_ITER': 235,
     'INSTRUMENTED_END_SEND': 236,
diff --git a/crates/codegen/src/compile.rs b/crates/codegen/src/compile.rs
index c41c2584523..93a759c7ff4 100644
--- a/crates/codegen/src/compile.rs
+++ b/crates/codegen/src/compile.rs
@@ -489,7 +489,7 @@ impl Compiler {
             match ctx {
                 ast::ExprContext::Load => {
                     emit!(self, Instruction::BuildSlice { argc });
-                    emit!(self, Instruction::Subscript);
+                    emit!(self, Instruction::BinarySubscr);
                 }
                 ast::ExprContext::Store => {
                     emit!(self, Instruction::BuildSlice { argc });
@@ -503,7 +503,7 @@ impl Compiler {
 
             // Emit appropriate instruction based on context
             match ctx {
-                ast::ExprContext::Load => emit!(self, Instruction::Subscript),
+                ast::ExprContext::Load => emit!(self, Instruction::BinarySubscr),
                 ast::ExprContext::Store => emit!(self, Instruction::StoreSubscr),
                 ast::ExprContext::Del => emit!(self, Instruction::DeleteSubscr),
                 ast::ExprContext::Invalid => {
@@ -5990,14 +5990,9 @@ impl Compiler {
             self.compile_addcompare(op);
 
             // if comparison result is false, we break with this value; if true, try the next one.
-            /*
             emit!(self, Instruction::Copy { index: 1 });
-            // emit!(self, Instruction::ToBool); // TODO: Uncomment this
             emit!(self, Instruction::PopJumpIfFalse { target: cleanup });
             emit!(self, Instruction::PopTop);
-            */
-
-            emit!(self, Instruction::JumpIfFalseOrPop { target: cleanup });
         }
 
         self.compile_expression(last_comparator)?;
@@ -6208,7 +6203,7 @@ impl Compiler {
                 self.compile_expression(slice)?;
                 emit!(self, Instruction::Copy { index: 2_u32 });
                 emit!(self, Instruction::Copy { index: 2_u32 });
-                emit!(self, Instruction::Subscript);
+                emit!(self, Instruction::BinarySubscr);
                 AugAssignKind::Subscript
             }
             ast::Expr::Attribute(ast::ExprAttribute { value, attr, .. }) => {
diff --git a/crates/compiler-core/src/bytecode/instruction.rs b/crates/compiler-core/src/bytecode/instruction.rs
index 040e46a5d89..d861b91300a 100644
--- a/crates/compiler-core/src/bytecode/instruction.rs
+++ b/crates/compiler-core/src/bytecode/instruction.rs
@@ -272,19 +272,12 @@ pub enum Instruction {
     Continue {
         target: Arg<Label>,
     } = 217,
-    JumpIfFalseOrPop {
-        target: Arg<Label>,
-    } = 218,
-    JumpIfTrueOrPop {
-        target: Arg<Label>,
-    } = 219,
     JumpIfNotExcMatch(Arg<Label>) = 220,
     LoadAssertionError = 221, // Placeholder
     ReturnConst {
         idx: Arg<u32>,
     } = 222,
     SetExcInfo = 223,
-    Subscript = 224,
     // CPython 3.14 RESUME (128)
     Resume {
         arg: Arg<u32>,
@@ -441,17 +434,10 @@ impl TryFrom<u8> for Instruction {
             u8::from(Self::Continue {
                 target: Arg::marker(),
             }),
-            u8::from(Self::JumpIfFalseOrPop {
-                target: Arg::marker(),
-            }),
-            u8::from(Self::JumpIfTrueOrPop {
-                target: Arg::marker(),
-            }),
             u8::from(Self::JumpIfNotExcMatch(Arg::marker())),
             u8::from(Self::LoadAssertionError),
             u8::from(Self::ReturnConst { idx: Arg::marker() }),
             u8::from(Self::SetExcInfo),
-            u8::from(Self::Subscript),
         ];
 
         if (cpython_start..=cpython_end).contains(&value)
@@ -478,8 +464,6 @@ impl InstructionMetadata for Instruction {
             | Self::JumpIfNotExcMatch(l)
             | Self::PopJumpIfTrue { target: l }
             | Self::PopJumpIfFalse { target: l }
-            | Self::JumpIfTrueOrPop { target: l }
-            | Self::JumpIfFalseOrPop { target: l }
             | Self::ForIter { target: l }
             | Self::Break { target: l }
             | Self::Continue { target: l }
@@ -525,7 +509,6 @@ impl InstructionMetadata for Instruction {
             Self::DeleteGlobal(_) => 0,
             Self::DeleteDeref(_) => 0,
             Self::LoadFromDictOrDeref(_) => 1,
-            Self::Subscript => -1,
             Self::StoreSubscr => -3,
             Self::DeleteSubscr => -2,
             Self::LoadAttr { .. } => 0,
@@ -551,20 +534,6 @@ impl InstructionMetadata for Instruction {
             Self::Break { .. } => 0,
             Self::PopJumpIfTrue { .. } => -1,
             Self::PopJumpIfFalse { .. } => -1,
-            Self::JumpIfTrueOrPop { .. } => {
-                if jump {
-                    0
-                } else {
-                    -1
-                }
-            }
-            Self::JumpIfFalseOrPop { .. } => {
-                if jump {
-                    0
-                } else {
-                    -1
-                }
-            }
             Self::MakeFunction => {
                 // CPython 3.14 style: MakeFunction only pops code object
                 -1 + 1 // pop code, push function
@@ -918,9 +887,7 @@ impl InstructionMetadata for Instruction {
             Self::JumpBackward { target } => w!(JUMP_BACKWARD, target),
             Self::JumpBackwardNoInterrupt { target } => w!(JUMP_BACKWARD_NO_INTERRUPT, target),
             Self::JumpForward { target } => w!(JUMP_FORWARD, target),
-            Self::JumpIfFalseOrPop { target } => w!(JUMP_IF_FALSE_OR_POP, target),
             Self::JumpIfNotExcMatch(target) => w!(JUMP_IF_NOT_EXC_MATCH, target),
-            Self::JumpIfTrueOrPop { target } => w!(JUMP_IF_TRUE_OR_POP, target),
             Self::ListAppend { i } => w!(LIST_APPEND, i),
             Self::ListExtend { i } => w!(LIST_EXTEND, i),
             Self::LoadAttr { idx } => {
@@ -992,7 +959,6 @@ impl InstructionMetadata for Instruction {
             Self::StoreGlobal(idx) => w!(STORE_GLOBAL, name = idx),
             Self::StoreName(idx) => w!(STORE_NAME, name = idx),
             Self::StoreSubscr => w!(STORE_SUBSCR),
-            Self::Subscript => w!(SUBSCRIPT),
             Self::Swap { index } => w!(SWAP, index),
             Self::ToBool => w!(TO_BOOL),
             Self::UnpackEx { args } => w!(UNPACK_EX, args),
diff --git a/crates/stdlib/src/opcode.rs b/crates/stdlib/src/opcode.rs
index 92d5d407aff..87ff871b732 100644
--- a/crates/stdlib/src/opcode.rs
+++ b/crates/stdlib/src/opcode.rs
@@ -107,9 +107,7 @@ mod opcode {
                     Instruction::Break { .. }
                         | Instruction::Continue { .. }
                         | Instruction::ForIter { .. }
-                        | Instruction::JumpIfFalseOrPop { .. }
                         | Instruction::JumpIfNotExcMatch(_)
-                        | Instruction::JumpIfTrueOrPop { .. }
                         | Instruction::PopJumpIfFalse { .. }
                         | Instruction::PopJumpIfTrue { .. }
                         | Instruction::Send { .. }
diff --git a/crates/vm/src/frame.rs b/crates/vm/src/frame.rs
index f6faf6f49cb..5f9343689a0 100644
--- a/crates/vm/src/frame.rs
+++ b/crates/vm/src/frame.rs
@@ -1139,9 +1139,6 @@ impl ExecutingFrame<'_> {
                 self.push_value(vm.ctx.new_bool(value).into());
                 Ok(None)
             }
-            Instruction::JumpIfFalseOrPop { target } => {
-                self.jump_if_or_pop(vm, target.get(arg), false)
-            }
             Instruction::JumpIfNotExcMatch(target) => {
                 let b = self.pop_value();
                 let a = self.pop_value();
@@ -1165,9 +1162,6 @@ impl ExecutingFrame<'_> {
                 self.push_value(vm.ctx.new_bool(value).into());
                 self.pop_jump_if(vm, target.get(arg), false)
             }
-            Instruction::JumpIfTrueOrPop { target } => {
-                self.jump_if_or_pop(vm, target.get(arg), true)
-            }
             Instruction::JumpForward { target } => {
                 self.jump(target.get(arg));
                 Ok(None)
@@ -1734,7 +1728,6 @@ impl ExecutingFrame<'_> {
                 Ok(None)
             }
             Instruction::StoreSubscr => self.execute_store_subscript(vm),
-            Instruction::Subscript => self.execute_subscript(vm),
             Instruction::Swap { index } => {
                 let len = self.state.stack.len();
                 debug_assert!(len > 0, "stack underflow in SWAP");
@@ -2074,14 +2067,6 @@ impl ExecutingFrame<'_> {
         }
     }
 
-    fn execute_subscript(&mut self, vm: &VirtualMachine) -> FrameResult {
-        let b_ref = self.pop_value();
-        let a_ref = self.pop_value();
-        let value = a_ref.get_item(&*b_ref, vm)?;
-        self.push_value(value);
-        Ok(None)
-    }
-
     fn execute_store_subscript(&mut self, vm: &VirtualMachine) -> FrameResult {
         let idx = self.pop_value();
         let obj = self.pop_value();
@@ -2351,23 +2336,6 @@ impl ExecutingFrame<'_> {
         Ok(None)
     }
 
-    #[inline]
-    fn jump_if_or_pop(
-        &mut self,
-        vm: &VirtualMachine,
-        target: bytecode::Label,
-        flag: bool,
-    ) -> FrameResult {
-        let obj = self.top_value();
-        let value = obj.to_owned().try_to_bool(vm)?;
-        if value == flag {
-            self.jump(target);
-        } else {
-            self.pop_value();
-        }
-        Ok(None)
-    }
-
     /// The top of stack contains the iterator, lets push it forward
     fn execute_for_iter(&mut self, vm: &VirtualMachine, target: bytecode::Label) -> FrameResult {
         let top_of_stack = PyIter::new(self.top_value());

From 3491aac7b0be15f8c0271a6dee0b14a8fc70f06a Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Tue, 20 Jan 2026 13:53:08 +0900
Subject: [PATCH 3/4] Remove LoadAssetionError

---
 Lib/_opcode_metadata.py                          | 1 -
 crates/compiler-core/src/bytecode/instruction.rs | 3 ---
 2 files changed, 4 deletions(-)

diff --git a/Lib/_opcode_metadata.py b/Lib/_opcode_metadata.py
index 2b18ad4d652..f219132b9c3 100644
--- a/Lib/_opcode_metadata.py
+++ b/Lib/_opcode_metadata.py
@@ -219,7 +219,6 @@
     'BREAK': 216,
     'CONTINUE': 217,
     'JUMP_IF_NOT_EXC_MATCH': 220,
-    'LOAD_ASSERTION_ERROR': 221,
     'RETURN_CONST': 222,
     'SET_EXC_INFO': 223,
     'INSTRUMENTED_END_FOR': 234,
diff --git a/crates/compiler-core/src/bytecode/instruction.rs b/crates/compiler-core/src/bytecode/instruction.rs
index d861b91300a..d8ba8da7a01 100644
--- a/crates/compiler-core/src/bytecode/instruction.rs
+++ b/crates/compiler-core/src/bytecode/instruction.rs
@@ -273,7 +273,6 @@ pub enum Instruction {
         target: Arg<Label>,
     } = 217,
     JumpIfNotExcMatch(Arg<Label>) = 220,
-    LoadAssertionError = 221, // Placeholder
     ReturnConst {
         idx: Arg<u32>,
     } = 222,
@@ -435,7 +434,6 @@ impl TryFrom<u8> for Instruction {
                 target: Arg::marker(),
             }),
             u8::from(Self::JumpIfNotExcMatch(Arg::marker())),
-            u8::from(Self::LoadAssertionError),
             u8::from(Self::ReturnConst { idx: Arg::marker() }),
             u8::from(Self::SetExcInfo),
         ];
@@ -651,7 +649,6 @@ impl InstructionMetadata for Instruction {
             Self::EndFor => 0,
             Self::ExitInitCheck => 0,
             Self::InterpreterExit => 0,
-            Self::LoadAssertionError => 0,
             Self::LoadLocals => 0,
             Self::ReturnGenerator => 0,
             Self::StoreSlice => 0,

From 9ee30aacef4737ba82f714cbee3344124414f975 Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Tue, 20 Jan 2026 14:00:42 +0900
Subject: [PATCH 4/4] Update snapshot for ForIter behavior change

---
 ...hon_codegen__compile__tests__nested_double_async_with.snap | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/codegen/src/snapshots/rustpython_codegen__compile__tests__nested_double_async_with.snap b/crates/codegen/src/snapshots/rustpython_codegen__compile__tests__nested_double_async_with.snap
index c4d2ed83796..eeef8ea4b3f 100644
--- a/crates/codegen/src/snapshots/rustpython_codegen__compile__tests__nested_double_async_with.snap
+++ b/crates/codegen/src/snapshots/rustpython_codegen__compile__tests__nested_double_async_with.snap
@@ -1,5 +1,6 @@
 ---
 source: crates/codegen/src/compile.rs
+assertion_line: 8626
 expression: "compile_exec(\"\\\nasync def test():\n    for stop_exc in (StopIteration('spam'), StopAsyncIteration('ham')):\n        with self.subTest(type=type(stop_exc)):\n            try:\n                async with egg():\n                    raise stop_exc\n            except Exception as ex:\n                self.assertIs(ex, stop_exc)\n            else:\n                self.fail(f'{stop_exc} was suppressed')\n\")"
 ---
   3           0 LOAD_CONST           (<code object test at ??? file "source_path", line 1>):  1               0 RESUME               (0)
@@ -140,7 +141,8 @@ expression: "compile_exec(\"\\\nasync def test():\n    for stop_exc in (StopIter
                 126 POP_EXCEPT
                 127 RERAISE              (1)
             >>  128 JUMP_BACKWARD        (11)
-            >>  129 RETURN_CONST         (None)
+            >>  129 POP_TOP
+                130 RETURN_CONST         (None)
 
               1 MAKE_FUNCTION
               2 STORE_NAME           (0, test)