PY-25045 Fixed: False positive: expected type '{__div__}', got 'Union[int, float]' instead

Update PyBinaryExpressionImpl to return `__truediv__` as referenced name instead of `__div__` when it is enabled.

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

@@ -17,6 +17,7 @@ package com.jetbrains.python.psi.impl;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
 import com.intellij.psi.PsiPolyVariantReference;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -24,6 +25,7 @@ import com.intellij.psi.util.QualifiedName;
 import com.intellij.util.IncorrectOperationException;
 import com.jetbrains.python.PyElementTypes;
 import com.jetbrains.python.PyNames;
+import com.jetbrains.python.PyTokenTypes;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.psi.impl.references.PyOperatorReference;
 import com.jetbrains.python.psi.resolve.PyResolveContext;
@@ -209,6 +211,9 @@ public class PyBinaryExpressionImpl extends PyElementImpl implements PyBinaryExp
   @Override
   public String getReferencedName() {
     final PyElementType t = getOperator();
+    if (t == PyTokenTypes.DIV && isTrueDivEnabled(this)) {
+      return PyNames.TRUEDIV;
+    }
     return t != null ? t.getSpecialMethodName() : null;
   }
 
@@ -217,4 +222,13 @@ public class PyBinaryExpressionImpl extends PyElementImpl implements PyBinaryExp
     final PsiElement op = getPsiOperator();
     return op != null ? op.getNode() : null;
   }
+
+  private static boolean isTrueDivEnabled(@NotNull PyElement anchor) {
+    final PsiFile file = anchor.getContainingFile();
+    if (file instanceof PyFile) {
+      final PyFile pyFile = (PyFile)file;
+      return FutureFeature.DIVISION.requiredAt(pyFile.getLanguageLevel()) || pyFile.hasImportFromFuture(FutureFeature.DIVISION);
+    }
+    return false;
+  }
 }

python/src/com/jetbrains/python/psi/impl/references/PyOperatorReference.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@ package com.jetbrains.python.psi.impl.references;
 
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiFile;
 import com.jetbrains.python.PyNames;
 import com.jetbrains.python.PyTokenTypes;
 import com.jetbrains.python.psi.*;
@@ -54,9 +53,6 @@ public class PyOperatorReference extends PyReferenceImpl {
         res = resolveMember(expr.getRightExpression(), name);
       }
       else {
-        if (PyNames.DIV.equals(name) && isTrueDivEnabled(myElement)) {
-          resolveLeftAndRightOperators(res, expr, PyNames.TRUEDIV);
-        }
         resolveLeftAndRightOperators(res, expr, name);
       }
     }
@@ -125,15 +121,6 @@ public class PyOperatorReference extends PyReferenceImpl {
     return name.replaceFirst("__([a-z]+)__", "__r$1__");
   }
 
-  private static boolean isTrueDivEnabled(@NotNull PyElement anchor) {
-    final PsiFile file = anchor.getContainingFile();
-    if (file instanceof PyFile) {
-      final PyFile pyFile = (PyFile)file;
-      return FutureFeature.DIVISION.requiredAt(pyFile.getLanguageLevel()) || pyFile.hasImportFromFuture(FutureFeature.DIVISION);
-    }
-    return false;
-  }
-
   private void resolveLeftAndRightOperators(List<RatedResolveResult> res, PyBinaryExpression expr, String name) {
     final TypeEvalContext typeEvalContext = myContext.getTypeEvalContext();
     typeEvalContext.trace("Trying to resolve left operator");

python/testData/inspections/PyTypeCheckerInspection/UnionOfIntAndFloatShouldBeConsideredAsDividable.py

@@ -0,0 +1,8 @@
+from typing import Union
+
+
+def foo(x):
+    return x / (60 * 60)
+
+bar = 0  # type: Union[int, float]
+foo(bar)

python/testData/types/NumpyResolveRaterDoesNotIncreaseRateForNotNdarrayRightOperatorFoundInStub/aaa.pyi

@@ -1,5 +1,5 @@
 class D1(object):
-    def __div__(self, other) -> "D1": ...
+    def __truediv__(self, other) -> "D1": ...
 
 class D2(object):
     def __rtruediv__(self, other) -> "D2": ...

python/testSrc/com/jetbrains/python/Py3TypeTest.java

@@ -483,7 +483,7 @@ public class Py3TypeTest extends PyTestCase {
 
   public void testNumpyResolveRaterDoesNotIncreaseRateForNotNdarrayRightOperatorFoundInStub() {
     myFixture.copyDirectoryToProject(TEST_DIRECTORY + getTestName(false), "");
-    doTest("Union[D2, D1]",
+    doTest("Union[D1, D2]",
            "class D1(object):\n" +
            "    pass\n" +
            "class D2(object):\n" +

python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java

@@ -255,4 +255,9 @@ public class Py3TypeCheckerInspectionTest extends PyTestCase {
   public void testPromotingBytearrayToBytes() {
     doTest();
   }
+
+  // PY-25045
+  public void testUnionOfIntAndFloatShouldBeConsideredAsDividable() {
+    doTest();
+  }
 }