From 17d5a4bbcedf3a45982d7a556d7b6d0b01690c87 Mon Sep 17 00:00:00 2001
From: Semyon Proshev <Semyon.Proshev@jetbrains.com>
Date: Tue, 14 Apr 2020 01:06:46 +0300
Subject: [PATCH] Restrict matching against callables (PY-29993, PY-28364)

Expected class-like types are not considered as callables (exclusion: bare typing.Callable).
Fix matching definition against metaclass.

GitOrigin-RevId: a2fe59c3bc7f56ef08dfb960a9ed841a86a65815
---
 .../python/psi/types/PyTypeChecker.java       |  9 ++++-
 .../ClassObjectAndMetaclassCompatibility.py   | 15 ++++++++
 .../PyTypeCheckerInspectionTest.java          | 35 +++++++++++++++++++
 3 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java b/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java
index 4d54b930b61a..b0f77c672d16 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java
@@ -11,6 +11,7 @@ import com.jetbrains.python.PyNames;
 import com.jetbrains.python.PythonRuntimeService;
 import com.jetbrains.python.codeInsight.dataflow.scope.ScopeUtil;
 import com.jetbrains.python.codeInsight.typing.PyProtocolsKt;
+import com.jetbrains.python.codeInsight.typing.PyTypingTypeProvider;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.psi.impl.PyBuiltinCache;
 import com.jetbrains.python.psi.impl.PyTypeProvider;
@@ -450,6 +451,12 @@ public class PyTypeChecker {
   private static Optional<Boolean> match(@NotNull PyCallableType expected,
                                          @NotNull PyCallableType actual,
                                          @NotNull MatchContext matchContext) {
+    if (expected instanceof PyClassLikeType) {
+      return PyTypingTypeProvider.CALLABLE.equals(((PyClassLikeType)expected).getClassQName())
+             ? Optional.of(actual.isCallable())
+             : Optional.empty();
+    }
+
     if (expected.isCallable() && actual.isCallable()) {
       final TypeEvalContext context = matchContext.context;
       final List<PyCallableParameter> expectedParameters = expected.getParameters(context);
@@ -489,7 +496,7 @@ public class PyTypeChecker {
       return false;
     }
     final PyClassLikeType metaClass = actual.getMetaClassType(context.context, true);
-    return metaClass != null && match(expected, metaClass, context).orElse(true);
+    return metaClass != null && match(expected, metaClass.toInstance(), context).orElse(true);
   }
 
   private static boolean typeVarAcceptsBothClassAndInstanceTypes(@NotNull PyGenericType typeVar) {
diff --git a/python/testData/inspections/PyTypeCheckerInspection/ClassObjectAndMetaclassCompatibility.py b/python/testData/inspections/PyTypeCheckerInspection/ClassObjectAndMetaclassCompatibility.py
index 5a8c75ab422d..403079b5030d 100644
--- a/python/testData/inspections/PyTypeCheckerInspection/ClassObjectAndMetaclassCompatibility.py
+++ b/python/testData/inspections/PyTypeCheckerInspection/ClassObjectAndMetaclassCompatibility.py
@@ -6,6 +6,10 @@ class SubMetaClass(MetaClass):
     pass
 
 
+class MetaClass2(type):
+    pass
+
+
 class MyClass(object):
     __metaclass__ = MetaClass
     pass
@@ -26,6 +30,15 @@ class MyClass3(Generated):
     pass
 
 
+class MyClass4:
+    __metaclass__ = MetaClass2
+    pass
+
+
+class MyClass5:
+    pass
+
+
 def f(x):
     # type: (MetaClass) -> None
     pass
@@ -35,3 +48,5 @@ f(MyClass)
 f(MyClass2)
 f(Generated)
 f(MyClass3)
+f(<warning descr="Expected type 'MetaClass', got 'Type[MyClass4]' instead">MyClass4</warning>)
+f(<warning descr="Expected type 'MetaClass', got 'Type[MyClass5]' instead">MyClass5</warning>)
diff --git a/python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java b/python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java
index 01c678cb9af2..b50fd0bf018a 100644
--- a/python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java
+++ b/python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java
@@ -1083,4 +1083,39 @@ public class PyTypeCheckerInspectionTest extends PyInspectionTestCase {
   public void testTypedDictInStub() {
     runWithLanguageLevel(LanguageLevel.getLatest(), this::doMultiFileTest);
   }
+
+  // PY-28364
+  public void testDefinitionAgainstCallableInstance() {
+    runWithLanguageLevel(
+      LanguageLevel.getLatest(),
+      () -> doTestByText("class B:\n" +
+                         "    def __call__(self, *args, **kwargs):\n" +
+                         "        pass\n" +
+                         "\n" +
+                         "def some_fn(arg: B):\n" +
+                         "    pass\n" +
+                         "\n" +
+                         "some_fn(<warning descr=\"Expected type 'B', got 'Type[B]' instead\">B</warning>)")
+    );
+  }
+
+  // PY-29993
+  public void testCallableInstanceAgainstOtherCallableInstance() {
+    runWithLanguageLevel(
+      LanguageLevel.getLatest(),
+      () -> doTestByText("class MyCls:\n" +
+                         "    def __call__(self):\n" +
+                         "        return True\n" +
+                         "\n" +
+                         "class DifferentCls:\n" +
+                         "    def __call__(self):\n" +
+                         "        return True\n" +
+                         "\n" +
+                         "def foo(arg: MyCls):\n" +
+                         "    pass\n" +
+                         "\n" +
+                         "foo(MyCls())\n" +
+                         "foo(<warning descr=\"Expected type 'MyCls', got 'DifferentCls' instead\">DifferentCls()</warning>)")
+    );
+  }
 }