Highlight type hints for non-self attributes

GitOrigin-RevId: 5afecdc4f073bb5ba5a495956fe30985b092634a

python/src/com/jetbrains/python/inspections/PyTypeHintsInspection.kt

@@ -124,6 +124,12 @@ class PyTypeHintsInspection : PyInspection() {
       checkTypeCommentAndParameters(node)
     }
 
+    override fun visitPyTargetExpression(node: PyTargetExpression) {
+      super.visitPyTargetExpression(node)
+
+      checkAnnotatedNonSelfAttribute(node)
+    }
+
     private fun checkTypeVarPlacement(call: PyCallExpression, target: PyExpression?) {
       if (target == null) {
         registerProblem(call, "A 'TypeVar()' expression must always directly be assigned to a variable")
@@ -597,6 +603,23 @@ class PyTypeHintsInspection : PyInspection() {
       }
     }
 
+    private fun checkAnnotatedNonSelfAttribute(node: PyTargetExpression) {
+      val qualifier = node.qualifier ?: return
+      if (node.annotation == null && node.typeComment == null) return
+
+      val scopeOwner = ScopeUtil.getScopeOwner(node)
+      if (scopeOwner !is PyFunction) {
+        registerProblem(node, "Non-self attribute could not be type hinted")
+        return
+      }
+
+      val self = scopeOwner.parameterList.parameters.firstOrNull()?.takeIf { it.isSelf }
+      if (self == null ||
+          PyUtil.multiResolveTopPriority(qualifier, resolveContext).let { it.isNotEmpty() && it.all { e -> e != self }}) {
+        registerProblem(node, "Non-self attribute could not be type hinted")
+      }
+    }
+
     private fun followNotTypingOpaque(target: PyTargetExpression): Boolean {
       return !PyTypingTypeProvider.OPAQUE_NAMES.contains(target.qualifiedName)
     }

python/testSrc/com/jetbrains/python/inspections/PyTypeHintsInspectionTest.java

@@ -848,6 +848,23 @@ public class PyTypeHintsInspectionTest extends PyInspectionTestCase {
     );
   }
 
+  public void testAnnotatingNonSelfAttribute() {
+    runWithLanguageLevel(
+      LanguageLevel.PYTHON36,
+      () -> doTestByText("class A:\n" +
+                         "    def method(self, b):\n" +
+                         "        <warning descr=\"Non-self attribute could not be type hinted\">b.a</warning>: int = 1\n" +
+                         "\n" +
+                         "class B:\n" +
+                         "    pass\n" +
+                         "\n" +
+                         "<warning descr=\"Non-self attribute could not be type hinted\">B.a</warning>: str = \"2\"\n" +
+                         "\n" +
+                         "def func(a):\n" +
+                         "    <warning descr=\"Non-self attribute could not be type hinted\">a.xxx</warning>: str = \"2\"")
+    );
+  }
+
   @NotNull
   @Override
   protected Class<? extends PyInspection> getInspectionClass() {