PEP 702 (@deprecated): improve the handling of explicit type annotations of assignment statements

mypy/checker.py

@@ -2930,14 +2930,10 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
         Handle all kinds of assignment statements (simple, indexed, multiple).
         """
 
-        if isinstance(s.rvalue, TempNode) and s.rvalue.no_rhs:
+        if s.unanalyzed_type is not None:
             for lvalue in s.lvalues:
-                if (
-                    isinstance(lvalue, NameExpr)
-                    and isinstance(var := lvalue.node, Var)
-                    and isinstance(instance := get_proper_type(var.type), Instance)
-                ):
-                    self.check_deprecated(instance.type, s)
+                if isinstance(lvalue, NameExpr) and isinstance(var := lvalue.node, Var):
+                    self.search_deprecated(var.type, s, set())
 
         # Avoid type checking type aliases in stubs to avoid false
         # positives about modern type syntax available in stubs such
@@ -7581,6 +7577,20 @@ def warn_deprecated(self, node: SymbolNode | None, context: Context) -> None:
             warn = self.msg.fail if self.options.report_deprecated_as_error else self.msg.note
             warn(deprecated, context, code=codes.DEPRECATED)
 
+    def search_deprecated(
+        self, typ: Type | None, s: AssignmentStmt, visited: set[Type | None]
+    ) -> None:
+
+        if typ not in visited:
+            visited.add(typ)
+            if isinstance(typ := get_proper_type(typ), Instance):
+                self.check_deprecated(typ.type, s)
+                for arg in typ.args:
+                    self.search_deprecated(arg, s, visited)
+            elif isinstance(typ, (UnionType, TupleType)):
+                for item in typ.items:
+                    self.search_deprecated(item, s, visited)
+
 
 class CollectArgTypeVarTypes(TypeTraverserVisitor):
     """Collects the non-nested argument types in a set."""

test-data/unit/check-deprecated.test

@@ -102,6 +102,7 @@ def h() -> None: ...
 
 [case testDeprecatedClass]
 
+from typing import List, Optional, Tuple, Union
 from typing_extensions import deprecated
 
 @deprecated("use C2 instead")
@@ -114,10 +115,30 @@ C.missing()  # N: class __main__.C is deprecated: use C2 instead \
 C.__init__(c)  # N: class __main__.C is deprecated: use C2 instead
 C(1)  # N: class __main__.C is deprecated: use C2 instead \
       # E: Too many arguments for "C"
+
 D = C  # N: class __main__.C is deprecated: use C2 instead
 D()
 t = (C, C, D)  # N: class __main__.C is deprecated: use C2 instead
 
+u1: Union[C, int] = 1  # N: class __main__.C is deprecated: use C2 instead
+u1 = 1
+u2 = 1  # type: Union[C, int]  # N: class __main__.C is deprecated: use C2 instead
+u2 = 1
+
+c1 = c2 = C()  # N: class __main__.C is deprecated: use C2 instead
+i, c3 = 1, C()  # N: class __main__.C is deprecated: use C2 instead
+
+class E: ...
+
+x1: Optional[C]  # N: class __main__.C is deprecated: use C2 instead
+x2: Union[D, C, E]  # N: class __main__.C is deprecated: use C2 instead
+x3: Union[D, Optional[C], E]  # N: class __main__.C is deprecated: use C2 instead
+x4: Tuple[D, C, E]  # N: class __main__.C is deprecated: use C2 instead
+x5: Tuple[Tuple[D, C], E]  # N: class __main__.C is deprecated: use C2 instead
+x6: List[C]  # N: class __main__.C is deprecated: use C2 instead
+x7: List[List[C]]  # N: class __main__.C is deprecated: use C2 instead
+x8: List[Optional[Tuple[Union[List[C], int]]]]  # N: class __main__.C is deprecated: use C2 instead
+
 [builtins fixtures/tuple.pyi]