Fix "not callable" issue for @dataclass(frozen=True) with Final attr

mypy/checkmember.py

@@ -755,8 +755,10 @@ def is_instance_var(var: Var) -> bool:
         var.name in var.info.names
         and var.info.names[var.name].node is var
         and not var.is_classvar
-        # variables without annotations are treated as classvar
-        and not var.is_inferred
+        # variables without annotations are treated as classvar,
+        # but not when they are annotated as `a: Final = 1`,
+        # since it will be inferenced as `Literal[1]`
+        and not (var.is_inferred and not var.is_final)
     )
 
 

test-data/unit/check-dataclasses.test

@@ -2553,3 +2553,18 @@ class X(metaclass=DCMeta):
 class Y(X):
     a: int  # E: Covariant override of a mutable attribute (base class "X" defined the type as "Optional[int]", expression has type "int")
 [builtins fixtures/tuple.pyi]
+
+
+[case testFrozenWithFinal]
+from dataclasses import dataclass
+from typing import Final
+
+@dataclass(frozen=True)
+class My:
+    a: Final = 1
+    b: Final[int] = 2
+
+m = My()
+reveal_type(m.a)  # N: Revealed type is "Literal[1]?"
+reveal_type(m.b)  # N: Revealed type is "builtins.int"
+[builtins fixtures/tuple.pyi]