RustPython · youknowone · Mar 27, 2026 · Mar 27, 2026 · Mar 27, 2026 · Mar 27, 2026
diff --git a/crates/codegen/src/compile.rs b/crates/codegen/src/compile.rs
@@ -1277,7 +1277,7 @@ impl Compiler {
                 context: OpArgMarker::marker(),
             }
             .into(),
-            arg: OpArg::new(u32::from(bytecode::ResumeType::AtFuncStart)),
+            arg: OpArg::new(oparg::ResumeLocation::AtFuncStart.into()),
             target: BlockIdx::NULL,
             location,
             end_location,
@@ -7200,9 +7200,9 @@ impl Compiler {
             self,
             Instruction::Resume {
                 context: if is_await {
-                    bytecode::ResumeType::AfterAwait
+                    oparg::ResumeContext::from(oparg::ResumeLocation::AfterAwait)
                 } else {
-                    bytecode::ResumeType::AfterYieldFrom
+                    oparg::ResumeContext::from(oparg::ResumeLocation::AfterYieldFrom)
                 }
             }
         );
@@ -7374,7 +7374,7 @@ impl Compiler {
                 emit!(
                     self,
                     Instruction::Resume {
-                        context: bytecode::ResumeType::AfterYield
+                        context: oparg::ResumeContext::from(oparg::ResumeLocation::AfterYield)
                     }
                 );
             }
@@ -7596,7 +7596,9 @@ impl Compiler {
                         emit!(
                             compiler,
                             Instruction::Resume {
-                                context: bytecode::ResumeType::AfterYield
+                                context: oparg::ResumeContext::from(
+                                    oparg::ResumeLocation::AfterYield
+                                )
                             }
                         );
                         emit!(compiler, Instruction::PopTop);

diff --git a/crates/codegen/src/ir.rs b/crates/codegen/src/ir.rs
@@ -363,7 +363,7 @@ impl CodeInfo {
             }
         }
 
-        let mut block_to_offset = vec![Label::new(0); blocks.len()];
+        let mut block_to_offset = vec![Label::from_u32(0); blocks.len()];
         // block_to_index: maps block idx to instruction index (for exception table)
         // This is the index into the final instructions array, including EXTENDED_ARG and CACHE
         let mut block_to_index = vec![0u32; blocks.len()];
@@ -372,7 +372,7 @@ impl CodeInfo {
         loop {
             let mut num_instructions = 0;
             for (idx, block) in iter_blocks(&blocks) {
-                block_to_offset[idx.idx()] = Label::new(num_instructions as u32);
+                block_to_offset[idx.idx()] = Label::from_u32(num_instructions as u32);
                 // block_to_index uses the same value as block_to_offset but as u32
                 // because lasti in frame.rs is the index into instructions array
                 // and instructions array index == byte offset (each instruction is 1 CodeUnit)
@@ -2188,20 +2188,19 @@ pub(crate) fn label_exception_targets(blocks: &mut [Block]) {
                 }
 
                 // Set RESUME DEPTH1 flag based on last yield's except depth
-                if matches!(
-                    blocks[bi].instructions[i].instr.real(),
-                    Some(Instruction::Resume { .. })
-                ) {
-                    const RESUME_AT_FUNC_START: u32 = 0;
-                    const RESUME_OPARG_LOCATION_MASK: u32 = 0x3;
-                    const RESUME_OPARG_DEPTH1_MASK: u32 = 0x4;
-
-                    if (u32::from(arg) & RESUME_OPARG_LOCATION_MASK) != RESUME_AT_FUNC_START {
-                        if last_yield_except_depth == 1 {
-                            blocks[bi].instructions[i].arg =
-                                OpArg::new(u32::from(arg) | RESUME_OPARG_DEPTH1_MASK);
+                if let Some(Instruction::Resume { context }) =
+                    blocks[bi].instructions[i].instr.real()
+                {
+                    let location = context.get(arg).location();
+                    match location {
+                        oparg::ResumeLocation::AtFuncStart => {}
+                        _ => {
+                            if last_yield_except_depth == 1 {
+                                blocks[bi].instructions[i].arg =
+                                    OpArg::new(oparg::ResumeContext::new(location, true).as_u32());
+                            }
+                            last_yield_except_depth = -1;
                         }
-                        last_yield_except_depth = -1;
                     }
                 }
 

diff --git a/crates/compiler-core/src/bytecode.rs b/crates/compiler-core/src/bytecode.rs
@@ -27,7 +27,7 @@ pub use crate::bytecode::{
         BinaryOperator, BuildSliceArgCount, CommonConstant, ComparisonOperator, ConvertValueOparg,
         IntrinsicFunction1, IntrinsicFunction2, Invert, Label, LoadAttr, LoadSuperAttr,
         MakeFunctionFlag, MakeFunctionFlags, NameIdx, OpArg, OpArgByte, OpArgState, OpArgType,
-        RaiseKind, ResumeType, SpecialMethod, UnpackExArgs,
+        RaiseKind, SpecialMethod, UnpackExArgs,
     },
 };
 
@@ -1041,7 +1041,7 @@ impl<C: Constant> CodeObject<C> {
             }
 
             // arrow and offset
-            let arrow = if label_targets.contains(&Label::new(offset as u32)) {
+            let arrow = if label_targets.contains(&Label::from_u32(offset as u32)) {
                 ">>"
             } else {
                 "  "

diff --git a/crates/compiler-core/src/bytecode/instruction.rs b/crates/compiler-core/src/bytecode/instruction.rs
@@ -304,7 +304,7 @@ pub enum Instruction {
     } = 120,
     // CPython 3.14 RESUME (128)
     Resume {
-        context: Arg<oparg::ResumeType>,
+        context: Arg<oparg::ResumeContext>,
     } = 128,
     // CPython 3.14 specialized opcodes (129-211)
     BinaryOpAddFloat = 129,                     // Placeholder

diff --git a/crates/compiler-core/src/bytecode/oparg.rs b/crates/compiler-core/src/bytecode/oparg.rs
@@ -276,48 +276,6 @@ impl fmt::Display for ConvertValueOparg {
     }
 }
 
-/// Resume type for the RESUME instruction
-#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
-pub enum ResumeType {
-    AtFuncStart,
-    AfterYield,
-    AfterYieldFrom,
-    AfterAwait,
-    Other(u32),
-}
-
-impl From<u32> for ResumeType {
-    fn from(value: u32) -> Self {
-        match value {
-            0 => Self::AtFuncStart,
-            5 => Self::AfterYield,
-            2 => Self::AfterYieldFrom,
-            3 => Self::AfterAwait,
-            _ => Self::Other(value),
-        }
-    }
-}
-
-impl From<ResumeType> for u32 {
-    fn from(typ: ResumeType) -> Self {
-        match typ {
-            ResumeType::AtFuncStart => 0,
-            ResumeType::AfterYield => 5,
-            ResumeType::AfterYieldFrom => 2,
-            ResumeType::AfterAwait => 3,
-            ResumeType::Other(v) => v,
-        }
-    }
-}
-
-impl core::fmt::Display for ResumeType {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        u32::from(*self).fmt(f)
-    }
-}
-
-impl OpArgType for ResumeType {}
-
 pub type NameIdx = u32;
 
 impl OpArgType for u32 {}
@@ -756,14 +714,8 @@ macro_rules! newtype_oparg {
         impl $name {
             /// Creates a new [`$name`] instance.
             #[must_use]
-            pub const fn new(value: u32) -> Self {
-                Self(value)
-            }
-
-            /// Alias to [`$name::new`].
-            #[must_use]
             pub const fn from_u32(value: u32) -> Self {
-                Self::new(value)
+                Self(value)
             }
 
             /// Returns the oparg as a `u32` value.
@@ -843,15 +795,119 @@ newtype_oparg!(
     pub struct Label(u32)
 );
 
+newtype_oparg!(
+    /// Context for [`Instruction::Resume`].
+    ///
+    /// The oparg consists of two parts:
+    /// 1. [`ResumeContext::location`]: Indicates where the instruction occurs.
+    /// 2. [`ResumeContext::is_exception_depth1`]: Is the instruction is at except-depth 1.
+    #[derive(Clone, Copy)]
+    #[repr(transparent)]
+    pub struct ResumeContext(u32)
+);
+
+impl ResumeContext {
+    /// [CPython `RESUME_OPARG_LOCATION_MASK`](https://github.com/python/cpython/blob/v3.14.3/Include/internal/pycore_opcode_utils.h#L84)
+    pub const LOCATION_MASK: u32 = 0x3;
+
+    /// [CPython `RESUME_OPARG_DEPTH1_MASK`](https://github.com/python/cpython/blob/v3.14.3/Include/internal/pycore_opcode_utils.h#L85)
+    pub const DEPTH1_MASK: u32 = 0x4;
+
+    #[must_use]
+    pub const fn new(location: ResumeLocation, is_exception_depth1: bool) -> Self {
+        let value = if is_exception_depth1 {
+            Self::DEPTH1_MASK
+        } else {
+            0
+        };
+
+        Self::from_u32(location.as_u32() | value)
+    }
+
+    /// Resume location is determined by [`Self::LOCATION_MASK`].
+    #[must_use]
+    pub fn location(&self) -> ResumeLocation {
+        // SAFETY: The mask should return a value that is in range.
+        unsafe { ResumeLocation::try_from(self.as_u32() & Self::LOCATION_MASK).unwrap_unchecked() }
+    }
+
+    /// True if the bit at [`Self::DEPTH1_MASK`] is on.
+    #[must_use]
+    pub const fn is_exception_depth1(&self) -> bool {
+        (self.as_u32() & Self::DEPTH1_MASK) != 0
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum ResumeLocation {
+    /// At the start of a function, which is neither a generator, coroutine nor an async generator.
+    AtFuncStart,
+    /// After a `yield` expression.
+    AfterYield,
+    /// After a `yield from` expression.
+    AfterYieldFrom,
+    /// After an `await` expression.
+    AfterAwait,
+}
+
+impl From<ResumeLocation> for ResumeContext {
+    fn from(location: ResumeLocation) -> Self {
+        Self::new(location, false)
+    }
+}
+
+impl TryFrom<u32> for ResumeLocation {
+    type Error = MarshalError;
+
+    fn try_from(value: u32) -> Result<Self, Self::Error> {
+        Ok(match value {
+            0 => Self::AtFuncStart,
+            1 => Self::AfterYield,
+            2 => Self::AfterYieldFrom,
+            3 => Self::AfterAwait,
+            _ => return Err(Self::Error::InvalidBytecode),
+        })
+    }
+}
+
+impl ResumeLocation {
+    #[must_use]
+    pub const fn as_u8(&self) -> u8 {
+        match self {
+            Self::AtFuncStart => 0,
+            Self::AfterYield => 1,
+            Self::AfterYieldFrom => 2,
+            Self::AfterAwait => 3,
+        }
+    }
+
+    #[must_use]
+    pub const fn as_u32(&self) -> u32 {
+        self.as_u8() as u32
+    }
+}
+
+impl From<ResumeLocation> for u8 {
+    fn from(location: ResumeLocation) -> Self {
+        location.as_u8()
+    }
+}
+
+impl From<ResumeLocation> for u32 {
+    fn from(location: ResumeLocation) -> Self {
+        location.as_u32()
+    }
+}
+
 impl VarNums {
     #[must_use]
     pub const fn idx_1(self) -> VarNum {
-        VarNum::new(self.0 >> 4)
+        VarNum::from_u32(self.0 >> 4)
     }
 
     #[must_use]
     pub const fn idx_2(self) -> VarNum {
-        VarNum::new(self.0 & 15)
+        VarNum::from_u32(self.0 & 15)
     }
 
     #[must_use]
@@ -887,7 +943,7 @@ impl LoadAttrBuilder {
     #[must_use]
     pub const fn build(self) -> LoadAttr {
         let value = (self.name_idx << 1) | (self.is_method as u32);
-        LoadAttr::new(value)
+        LoadAttr::from_u32(value)
     }
 
     #[must_use]
@@ -937,7 +993,7 @@ impl LoadSuperAttrBuilder {
     pub const fn build(self) -> LoadSuperAttr {
         let value =
             (self.name_idx << 2) | ((self.has_class as u32) << 1) | (self.is_load_method as u32);
-        LoadSuperAttr::new(value)
+        LoadSuperAttr::from_u32(value)
     }
 
     #[must_use]

diff --git a/crates/jit/src/instructions.rs b/crates/jit/src/instructions.rs
@@ -162,7 +162,7 @@ impl<'a, 'b> FunctionCompiler<'a, 'b> {
         let target = after
             .checked_add(u32::from(arg))
             .ok_or(JitCompileError::BadBytecode)?;
-        Ok(Label::new(target))
+        Ok(Label::from_u32(target))
     }
 
     fn jump_target_backward(
@@ -177,7 +177,7 @@ impl<'a, 'b> FunctionCompiler<'a, 'b> {
         let target = after
             .checked_sub(u32::from(arg))
             .ok_or(JitCompileError::BadBytecode)?;
-        Ok(Label::new(target))
+        Ok(Label::from_u32(target))
     }
 
     fn instruction_target(
@@ -232,7 +232,7 @@ impl<'a, 'b> FunctionCompiler<'a, 'b> {
         let mut in_unreachable_code = false;
 
         for (offset, &raw_instr) in clean_instructions.iter().enumerate() {
-            let label = Label::new(offset as u32);
+            let label = Label::from_u32(offset as u32);
             let (instruction, arg) = arg_state.get(raw_instr);
 
             // If this is a label that some earlier jump can target,