Fixed analyzing calls of properties that return callables (PY-9605)

python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java

@@ -176,6 +176,21 @@ public class PyCallExpressionHelper {
         else if (PyNames.STATICMETHOD.equals(wrapper_name)) wrappedModifier = PyFunction.Modifier.STATICMETHOD;
       }
     }
+    final List<PyExpression> qualifiers = resolveResult != null ? resolveResult.getQualifiers() : Collections.<PyExpression>emptyList();
+    final TypeEvalContext context = resolveContext.getTypeEvalContext();
+    if (resolved instanceof PyFunction) {
+      final PyFunction function = (PyFunction)resolved;
+      final Property property = function.getProperty();
+      if (property != null && isQualifiedByInstance(function, qualifiers, context)) {
+        final PyType type = function.getReturnType(context, null);
+        if (type instanceof PyFunctionType) {
+          resolved = ((PyFunctionType)type).getCallable();
+        }
+        else {
+          resolved = null;
+        }
+      }
+    }
     if (resolved instanceof Callable) {
       PyFunction.Modifier modifier = resolved instanceof PyFunction
                                    ? ((PyFunction)resolved).getModifier()
@@ -183,12 +198,10 @@ public class PyCallExpressionHelper {
       if (modifier == null && wrappedModifier != null) {
         modifier = wrappedModifier;
       }
-      List<PyExpression> qualifiers = resolveResult != null ? resolveResult.getQualifiers() : Collections.<PyExpression>emptyList();
-      boolean isByInstance = isConstructorCall ||
-                               isQualifiedByInstance((Callable)resolved, qualifiers, resolveContext.getTypeEvalContext())
-                               || resolved instanceof PyBoundFunction;
+      boolean isByInstance = isConstructorCall || isQualifiedByInstance((Callable)resolved, qualifiers, context)
+                             || resolved instanceof PyBoundFunction;
       PyExpression lastQualifier = qualifiers != null && qualifiers.isEmpty() ? null : qualifiers.get(qualifiers.size()-1);
-      boolean isByClass = lastQualifier == null ? false : isQualifiedByClass((Callable)resolved, lastQualifier, resolveContext.getTypeEvalContext());
+      boolean isByClass = lastQualifier == null ? false : isQualifiedByClass((Callable)resolved, lastQualifier, context);
       final Callable callable = (Callable)resolved;
 
       implicitOffset += getImplicitArgumentCount(callable, modifier, isConstructorCall, isByInstance, isByClass);

python/testData/inspections/PyArgumentListInspection/propertyReturnsCallable.py

@@ -0,0 +1,10 @@
+class C(object):
+    @property
+    def f(self):
+        return lambda x, y: (x, y)
+
+
+c = C()
+c.f(1, 2)
+c.f(<warning descr="Parameter 'x' unfilled"><warning descr="Parameter 'y' unfilled">)</warning></warning>
+c.f(1, 2, <warning descr="Unexpected argument">3</warning>)

python/testSrc/com/jetbrains/python/PyTypeTest.java

@@ -771,6 +771,19 @@ public class PyTypeTest extends PyTestCase {
            "        expr = self\n");
   }
 
+  // PY-9605
+  public void testPropertyReturnsCallable() {
+    doTest("() -> int",
+           "class C(object):\n" +
+           "    @property\n" +
+           "    def foo(self):\n" +
+           "        return lambda: 0\n" +
+           "\n" +
+
+           "c = C()\n" +
+           "expr = c.foo\n");
+  }
+
   private static TypeEvalContext getTypeEvalContext(@NotNull PyExpression element) {
     return TypeEvalContext.userInitiated(element.getContainingFile()).withTracing();
   }

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

@@ -138,4 +138,9 @@ public class PyArgumentListInspectionTest extends PyTestCase {
   public void testDecoratedChangedParameters() {
     doTest();
   }
+
+  // PY-9605
+  public void testPropertyReturnsCallable() {
+    doTest();
+  }
 }