New semantic analyzer: fix properties (#6396)

Fixes #6295.

Author: JukkaL

mypy/newsemanal/semanal.py

@@ -2832,11 +2832,9 @@ def visit_decorator(self, dec: Decorator) -> None:
                     self.fail("@final cannot be used with non-method functions", d)
         for i in reversed(removed):
             del dec.decorators[i]
-        if not dec.is_overload or dec.var.is_property:
-            if self.type:
-                dec.var.info = self.type
-                dec.var.is_initialized_in_class = True
-            self.add_symbol(dec.var.name(), dec, dec)
+        if (not dec.is_overload or dec.var.is_property) and self.type:
+            dec.var.info = self.type
+            dec.var.is_initialized_in_class = True
         if not no_type_check and self.recurse_into_functions:
             dec.func.accept(self)
         if dec.decorators and dec.var.is_property:

test-data/unit/check-newsemanal.test

@@ -1054,3 +1054,24 @@ class Test:
     import a
     def __init__(self) -> None:
         some_module = self.a
+
+[case testNewAnalyzerProperty]
+class A:
+    @property
+    def x(self) -> B:
+        return 0  # E: Incompatible return value type (got "int", expected "B")
+
+    @property
+    def y(self) -> B:
+        pass
+
+    @y.setter
+    def y(self, x: B) -> None:
+        pass
+
+class B: pass
+
+a = A()
+reveal_type(a.x)  # E: Revealed type is '__main__.B'
+a.y = 1  # E: Incompatible types in assignment (expression has type "int", variable has type "B")
+[builtins fixtures/property.pyi]

test-data/unit/pythoneval.test

@@ -1368,5 +1368,4 @@ reveal_type(x['test'][0])
 typing.pyi:251: error: Class typing.Sequence has abstract attributes "__len__"
 typing.pyi:251: note: If it is meant to be abstract, add 'abc.ABCMeta' as an explicit metaclass
 ast.pyi:31: error: Name 'PyCF_ONLY_AST' already defined (possibly by an import)
-builtins.pyi:39: error: Name '__class__' already defined on line 39
 _testNewAnalyzerBasicTypeshed_newsemanal.py:4: error: Revealed type is 'builtins.int*'