[mypyc] feat: exact_dict_rprimitive

Author: BobTheBuidler

mypyc/ir/rtypes.py

@@ -487,8 +487,13 @@ def __hash__(self) -> int:
     "builtins.list", is_unboxed=False, is_refcounted=True, may_be_immortal=False
 )
 
-# Python dict object (or an instance of a subclass of dict).
+# Python dict object.
+exact_dict_rprimitive: Final = RPrimitive(
+    "builtins.dict[exact]", is_unboxed=False, is_refcounted=True)
+)
+
 dict_rprimitive: Final = RPrimitive("builtins.dict", is_unboxed=False, is_refcounted=True)
+# An instance of a subclass of dict.
 
 # Python set object (or an instance of a subclass of set).
 set_rprimitive: Final = RPrimitive("builtins.set", is_unboxed=False, is_refcounted=True)
@@ -599,7 +604,14 @@ def is_list_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
 
 
 def is_dict_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
-    return isinstance(rtype, RPrimitive) and rtype.name == "builtins.dict"
+    return isinstance(rtype, RPrimitive) and rtype.name in (
+        "builtins.dict",
+        "builtins.dict[exact]",
+    )
+
+
+def is_exact_dict_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
+    return isinstance(rtype, RPrimitive) and rtype.name == "builtins.dict[exact]"
 
 
 def is_set_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]: