Remove Instruction::MapAddRev

Author: youknowone

bytecode/src/lib.rs

@@ -393,13 +393,6 @@ pub enum Instruction {
     GetAIter,
     GetANext,
     EndAsyncFor,
-
-    /// Reverse order evaluation in MapAdd
-    /// required to support named expressions of Python 3.8 in dict comprehension
-    /// today (including Py3.9) only required in dict comprehension.
-    MapAddRev {
-        i: u32,
-    },
 }
 
 use self::Instruction::*;
@@ -1024,7 +1017,7 @@ impl Instruction {
             }
             BuildSlice { step } => -2 - (*step as i32) + 1,
             ListAppend { .. } | SetAdd { .. } => -1,
-            MapAdd { .. } | MapAddRev { .. } => -2,
+            MapAdd { .. } => -2,
             PrintExpr => -1,
             LoadBuildClass => 1,
             UnpackSequence { size } => -1 + *size as i32,
@@ -1187,7 +1180,7 @@ impl Instruction {
             BuildSlice { step } => w!(BuildSlice, step),
             ListAppend { i } => w!(ListAppend, i),
             SetAdd { i } => w!(SetAdd, i),
-            MapAddRev { i } => w!(MapAddRev, i),
+            MapAdd { i } => w!(MapAdd, i),
             PrintExpr => w!(PrintExpr),
             LoadBuildClass => w!(LoadBuildClass),
             UnpackSequence { size } => w!(UnpackSequence, size),
@@ -1199,7 +1192,6 @@ impl Instruction {
             GetAIter => w!(GetAIter),
             GetANext => w!(GetANext),
             EndAsyncFor => w!(EndAsyncFor),
-            MapAdd { i } => w!(MapAdd, i),
         }
     }
 }

compiler/src/compile.rs

@@ -2136,7 +2136,7 @@ impl Compiler {
                         compiler.compile_expression(key)?;
                         compiler.compile_expression(value)?;
 
-                        compiler.emit(Instruction::MapAddRev {
+                        compiler.emit(Instruction::MapAdd {
                             i: generators.len() as u32,
                         });
 

vm/src/frame.rs

@@ -688,18 +688,6 @@ impl ExecutingFrame<'_> {
                 Ok(None)
             }
             bytecode::Instruction::MapAdd { i } => {
-                let key = self.pop_value();
-                let value = self.pop_value();
-                let obj = self.nth_value(*i);
-                let dict: &Py<PyDict> = unsafe {
-                    // SAFETY: trust compiler
-                    obj.downcast_unchecked_ref()
-                };
-                dict.set_item(&*key, value, vm)?;
-                Ok(None)
-            }
-            bytecode::Instruction::MapAddRev { i } => {
-                // change order of evalutio of key and value to support Py3.8 Named expressions in dict comprehension
                 let value = self.pop_value();
                 let key = self.pop_value();
                 let obj = self.nth_value(*i);