[mypyc] feat: exact_dict_rprimitive

mypyc/analysis/ircheck.py

@@ -197,7 +197,10 @@ def can_coerce_to(src: RType, dest: RType) -> bool:
         if isinstance(src, RPrimitive):
             # If either src or dest is a disjoint type, then they must both be.
             if src.name in disjoint_types and dest.name in disjoint_types:
-                return src.name == dest.name
+                return src.name == dest.name or (
+                    src.name in ("builtins.dict", "builtins.dict[exact]")
+                    and dest.name in ("builtins.dict", "builtins.dict[exact]")
+                )
             return src.size == dest.size
         if isinstance(src, RInstance):
             return is_object_rprimitive(dest)

mypyc/ir/rtypes.py

@@ -487,7 +487,12 @@ 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
+)
+
+# An instance of a subclass of dict.
 dict_rprimitive: Final = RPrimitive("builtins.dict", is_unboxed=False, is_refcounted=True)
 
 # Python set object (or an instance of a subclass of set).
@@ -608,7 +613,14 @@ 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]:

mypyc/primitives/misc_ops.py

@@ -13,6 +13,7 @@
     c_pyssize_t_rprimitive,
     cstring_rprimitive,
     dict_rprimitive,
+    exact_dict_rprimitive,
     float_rprimitive,
     int_rprimitive,
     none_rprimitive,
@@ -160,7 +161,7 @@
 # Get the sys.modules dictionary
 get_module_dict_op = custom_op(
     arg_types=[],
-    return_type=dict_rprimitive,
+    return_type=exact_dict_rprimitive,
     c_function_name="PyImport_GetModuleDict",
     error_kind=ERR_NEVER,
     is_borrowed=True,

mypyc/rt_subtype.py

@@ -27,6 +27,8 @@
     RVoid,
     is_bit_rprimitive,
     is_bool_rprimitive,
+    is_dict_rprimitive,
+    is_exact_dict_rprimitive,
     is_int_rprimitive,
     is_short_int_rprimitive,
 )
@@ -58,6 +60,8 @@ def visit_rprimitive(self, left: RPrimitive) -> bool:
             return True
         if is_bit_rprimitive(left) and is_bool_rprimitive(self.right):
             return True
+        if is_exact_dict_rprimitive(left) and is_dict_rprimitive(self.right):
+            return True
         return left is self.right
 
     def visit_rtuple(self, left: RTuple) -> bool:

mypyc/subtype.py

@@ -14,6 +14,8 @@
     RVoid,
     is_bit_rprimitive,
     is_bool_rprimitive,
+    is_dict_rprimitive,
+    is_exact_dict_rprimitive,
     is_fixed_width_rtype,
     is_int_rprimitive,
     is_object_rprimitive,
@@ -67,6 +69,9 @@ def visit_rprimitive(self, left: RPrimitive) -> bool:
         elif is_fixed_width_rtype(left):
             if is_int_rprimitive(right):
                 return True
+        elif is_exact_dict_rprimitive(left):
+            if is_dict_rprimitive(right):
+                return True
         return left is right
 
     def visit_rtuple(self, left: RTuple) -> bool:

mypyc/test-data/irbuild-basic.test

@@ -3270,7 +3270,7 @@ def root():
     r4 :: str
     r5 :: object
     r6 :: str
-    r7 :: dict
+    r7 :: dict[exact]
     r8 :: str
     r9 :: object
     r10 :: i32
@@ -3281,7 +3281,7 @@ def root():
     r16 :: str
     r17 :: object
     r18 :: str
-    r19 :: dict
+    r19 :: dict[exact]
     r20 :: str
     r21 :: object
     r22 :: i32
@@ -3327,12 +3327,12 @@ def submodule():
     r4 :: str
     r5 :: object
     r6 :: str
-    r7 :: dict
+    r7 :: dict[exact]
     r8 :: str
     r9 :: object
     r10 :: i32
     r11 :: bit
-    r12 :: dict
+    r12 :: dict[exact]
     r13 :: str
     r14 :: object
     r15 :: str