gh-105775: Add unit test, correct NEWS/docs

This change adds a unit test for assembly of code objects containing the LOAD_CLOSURE pseud-instruction We also correct the documentation and NEWS descriptions to more accurately reflect the effects of converting LOAD_CLOSURE to a pseudo-op and the reason for its existence in the first place
python · gvanrossum · Jun 29, 2023 · Jun 24, 2023 · Jun 24, 2023 · Jun 25, 2023
commit 93b3138aaaf3ed844814917c027a6f53731b3900
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
@@ -1719,7 +1719,6 @@ but are replaced by real opcodes or removed before bytecode is generated.
    storage.
 
    Note that ``LOAD_CLOSURE`` is replaced with ``LOAD_FAST`` in the assembler.
-   It exists to keep bytecode a little more readable.
 
    .. versionchanged:: 3.13
       This opcode was demoted from full opcode to pseudo-instruction
-      This opcode was demoted from full opcode to pseudo-instruction
+      This opcode is now a pseudo-instruction.
-      This opcode was demoted from full opcode to pseudo-instruction
+      This opcode is now a pseudo-instruction.

diff --git a/Lib/test/test_compiler_assemble.py b/Lib/test/test_compiler_assemble.py
@@ -70,3 +70,40 @@ def test_simple_expr(self):
         ]
         expected = {(3, 4) : 3.5, (-100, 200) : 50, (10, 18) : 14}
         self.assemble_test(insts, metadata, expected)
+
+
+    def test_expression_with_pseudo_instruction_load_closure(self):
+
+        def mod_two(x):
+            def inner():
+                return x
+            return inner() % 2
+
+        inner_code = mod_two.__code__.co_consts[1]
+
+        metadata = {
+            'filename' : 'mod_two.py',
+            'name'     : 'mod_two',
+            'qualname' : 'nested.mod_two',
+            'cellvars' : {'x' : 0},
+            'consts': {None: 0, inner_code: 1, 2: 2},
+            'argcount' : 1,
+            'varnames' : {'x' : 0},
+        }
+
+        instructions = [
+            ('RESUME', 0,),
+            ('PUSH_NULL', 0, 1),
+            ('LOAD_CLOSURE', 0, 1),
+            ('BUILD_TUPLE', 1, 1),
+            ('LOAD_CONST', 1, 1),
+            ('MAKE_FUNCTION', 0, 2),
+            ('SET_FUNCTION_ATTRIBUTE', 8, 2),
+            ('CALL', 0, 2),                     # (lambda: x)()
+            ('LOAD_CONST', 2, 2),               # 2
+            ('BINARY_OP', 6, 2),                # %
+            ('RETURN_VALUE', 0, 2)
+        ]
+
+        expected = {(0,): 0, (1,): 1, (2,): 0, (120,): 0, (121,): 1}
+        self.assemble_test(instructions, metadata, expected)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-06-24-10-34-27.gh-issue-105775.OqjoGV.rst b/Misc/NEWS.d/next/Core and Builtins/2023-06-24-10-34-27.gh-issue-105775.OqjoGV.rst
@@ -1,4 +1 @@
-Remove the LOAD_CLOSURE opcode and make it a pseudo-op instead. This enables
-
-* Superinstruction formation
-* Removal of checks for uninitialized variables
+Remove the LOAD_CLOSURE opcode and make it a pseudo-op instead.