updated tests to provide note to use None guard when accessing attrib…

…utes on union types
python · angelawuuu · Apr 23, 2024 · Apr 23, 2024 · Apr 24, 2024 · Apr 24, 2024
commit a65ac35b1571407037c5f290df9c4a8b3846c3dd
diff --git a/test-data/unit/check-inference.test b/test-data/unit/check-inference.test
@@ -2828,15 +2828,17 @@ class C:
     a = None  # E: Need type annotation for "a" (hint: "a: Optional[<type>] = ...")
 
     def f(self, x) -> None:
-        C.a.y  # E: Item "None" of "Optional[Any]" has no attribute "y"
+        C.a.y # E: Item "None" of "Optional[Any]" has no attribute "y" \
+              # N: You can use "if C.a is not None" to guard against a None value
 
 [case testLocalPartialTypesAccessPartialNoneAttribute2]
 # flags: --local-partial-types
 class C:
     a = None  # E: Need type annotation for "a" (hint: "a: Optional[<type>] = ...")
 
     def f(self, x) -> None:
-        self.a.y  # E: Item "None" of "Optional[Any]" has no attribute "y"
+        self.a.y  # E: Item "None" of "Optional[Any]" has no attribute "y" \
+                  # N: You can use "if self.a is not None" to guard against a None value
 
 -- Special case for assignment to '_'
 -- ----------------------------------

diff --git a/test-data/unit/check-optional.test b/test-data/unit/check-optional.test
@@ -564,7 +564,8 @@ if int():
 if int():
     x = f('x') # E: Argument 1 to "f" has incompatible type "str"; expected "int"
 
-x.x = 1 # E: Item "None" of "Optional[Node[int]]" has no attribute "x"
+x.x = 1 # E: Item "None" of "Optional[Node[int]]" has no attribute "x" \
+        # N: You can use "if x is not None" to guard against a None value
 if x is not None:
     x.x = 1 # OK here
 
@@ -617,7 +618,8 @@ A = None  # type: Any
 class C(A):
     pass
 x = None  # type: Optional[C]
-x.foo()  # E: Item "None" of "Optional[C]" has no attribute "foo"
+x.foo()   # E: Item "None" of "Optional[C]" has no attribute "foo" \
+          # N: You can use "if x is not None" to guard against a None value
 
 [case testIsinstanceAndOptionalAndAnyBase]
 from typing import Any, Optional

diff --git a/test-data/unit/check-unions.test b/test-data/unit/check-unions.test
@@ -935,7 +935,8 @@ a: Any
 d: Dict[str, Tuple[List[Tuple[str, str]], str]]
 x, _ = d.get(a, (None, None))
 
-for y in x: pass # E: Item "None" of "Optional[List[Tuple[str, str]]]" has no attribute "__iter__" (not iterable)
+for y in x: pass  # E: Item "None" of "Optional[List[Tuple[str, str]]]" has no attribute "__iter__" (not iterable) \
+                  # N: You can use "if x is not None" to guard against a None value
 if x:
     for s, t in x:
         reveal_type(s) # N: Revealed type is "builtins.str"
@@ -950,7 +951,8 @@ x = None
 d: Dict[str, Tuple[List[Tuple[str, str]], str]]
 x, _ = d.get(a, (None, None))
 
-for y in x: pass # E: Item "None" of "Optional[List[Tuple[str, str]]]" has no attribute "__iter__" (not iterable)
+for y in x: pass  # E: Item "None" of "Optional[List[Tuple[str, str]]]" has no attribute "__iter__" (not iterable) \
+                  # N: You can use "if x is not None" to guard against a None value
 if x:
     for s, t in x:
         reveal_type(s) # N: Revealed type is "builtins.str"