PY-22971 Fixed: Support @typing.overload in regular Python files, not only in Python stubs

Update PyRedeclarationInspection to not consider preceding overloads as write elements for the following implementation.

python/src/com/jetbrains/python/inspections/PyRedeclarationInspection.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.
@@ -26,7 +26,6 @@ import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiElementVisitor;
 import com.intellij.psi.PsiNameIdentifierOwner;
 import com.intellij.psi.util.PsiTreeUtil;
-import com.intellij.util.Function;
 import com.jetbrains.python.PyBundle;
 import com.jetbrains.python.PyNames;
 import com.jetbrains.python.codeInsight.controlflow.ControlFlowCache;
@@ -35,6 +34,7 @@ import com.jetbrains.python.codeInsight.controlflow.ScopeOwner;
 import com.jetbrains.python.codeInsight.dataflow.scope.ScopeUtil;
 import com.jetbrains.python.inspections.quickfix.PyRenameElementQuickFix;
 import com.jetbrains.python.psi.*;
+import com.jetbrains.python.pyi.PyiTypeProvider;
 import org.jetbrains.annotations.Nls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -49,6 +49,7 @@ import java.util.List;
  * @author vlan
  */
 public class PyRedeclarationInspection extends PyInspection {
+  @Override
   @Nls
   @NotNull
   public String getDisplayName() {
@@ -136,8 +137,11 @@ public class PyRedeclarationInspection extends PyInspection {
                 if (rwInstruction.getAccess().isReadAccess()) {
                   readElementRef.set(originalElement);
                 }
-                if (rwInstruction.getAccess().isWriteAccess()) {
-                  if (originalElement != element) {
+                if (rwInstruction.getAccess().isWriteAccess() && originalElement != element) {
+                  if (element instanceof PyCallable && isOverload(originalElement)) {
+                    return ControlFlowUtil.Operation.NEXT;
+                  }
+                  else {
                     writeElementRef.set(originalElement);
                   }
                 }
@@ -163,6 +167,10 @@ public class PyRedeclarationInspection extends PyInspection {
       }
     }
 
+    private boolean isOverload(@NotNull PsiElement element) {
+      return element instanceof PyCallable && PyiTypeProvider.isOverload((PyCallable)element, myTypeEvalContext);
+    }
+
     private static boolean suggestRename(@NotNull PsiNameIdentifierOwner element, @NotNull PsiElement originalElement) {
       // Target expressions in the same scope are treated as the same variable
       if ((element instanceof PyTargetExpression) && originalElement instanceof PyTargetExpression) {

python/testData/inspections/PyRedeclarationInspection/overloadImplementationOverloadImplementationInClass.py

@@ -0,0 +1,17 @@
+from typing import overload
+
+
+class A:
+    @overload
+    def foo(self, value: int) -> str:
+        pass
+
+    def foo(self, value):
+        return None
+
+    @overload
+    def foo(self, value: str) -> str:
+        pass
+
+    def <warning descr="Redeclared 'foo' defined above without usage">foo</warning>(self, value):
+        return None

python/testData/inspections/PyRedeclarationInspection/overloadsAndImplementationInClass.py

@@ -0,0 +1,18 @@
+from typing import overload
+
+
+class A:
+    @overload
+    def utf8(self, value: None) -> None:
+        pass
+
+    @overload
+    def utf8(self, value: bytes) -> bytes:
+        pass
+
+    @overload
+    def utf8(self, value: str) -> bytes:
+        pass
+
+    def utf8(self, value):
+        return None

python/testData/inspections/PyRedeclarationInspection/overloadsAndImplementationsInClass.py

@@ -0,0 +1,21 @@
+from typing import overload
+
+
+class A:
+    @overload
+    def utf8(self, value: None) -> None:
+        pass
+
+    @overload
+    def utf8(self, value: bytes) -> bytes:
+        pass
+
+    @overload
+    def utf8(self, value: str) -> bytes:
+        pass
+
+    def utf8(self, value):
+        return None
+
+    def <warning descr="Redeclared 'utf8' defined above without usage">utf8</warning>(self, value):
+        return None

python/testData/inspections/PyRedeclarationInspection/topLevelOverloadImplementationOverloadImplementation.py

@@ -0,0 +1,19 @@
+from typing import overload
+
+
+@overload
+def foo(value: int) -> str:
+    pass
+
+
+def foo(value):
+    return None
+
+
+@overload
+def foo(value: str) -> str:
+    pass
+
+
+def <warning descr="Redeclared 'foo' defined above without usage">foo</warning>(value):
+    return None

python/testData/inspections/PyRedeclarationInspection/topLevelOverloadsAndImplementation.py

@@ -0,0 +1,20 @@
+from typing import overload
+
+
+@overload
+def utf8(value: None) -> None:
+    pass
+
+
+@overload
+def utf8(value: bytes) -> bytes:
+    pass
+
+
+@overload
+def utf8(value: str) -> bytes:
+    pass
+
+
+def utf8(value):
+    return None

python/testData/inspections/PyRedeclarationInspection/topLevelOverloadsAndImplementations.py

@@ -0,0 +1,24 @@
+from typing import overload
+
+
+@overload
+def utf8(value: None) -> None:
+    pass
+
+
+@overload
+def utf8(value: bytes) -> bytes:
+    pass
+
+
+@overload
+def utf8(value: str) -> bytes:
+    pass
+
+
+def utf8(value):
+    return None
+
+
+def <warning descr="Redeclared 'utf8' defined above without usage">utf8</warning>(value):
+    return None

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

@@ -16,6 +16,7 @@
 package com.jetbrains.python.inspections;
 
 import com.jetbrains.python.fixtures.PyTestCase;
+import com.jetbrains.python.psi.LanguageLevel;
 
 public class PyRedeclarationInspectionTest extends PyTestCase {
 
@@ -63,6 +64,36 @@ public class PyRedeclarationInspectionTest extends PyTestCase {
     doTest();
   }
 
+  // PY-22971
+  public void testTopLevelOverloadsAndImplementation() {
+    runWithLanguageLevel(LanguageLevel.PYTHON36, this::doTest);
+  }
+
+  // PY-22971
+  public void testOverloadsAndImplementationInClass() {
+    runWithLanguageLevel(LanguageLevel.PYTHON36, this::doTest);
+  }
+
+  // PY-22971
+  public void testTopLevelOverloadsAndImplementations() {
+    runWithLanguageLevel(LanguageLevel.PYTHON36, this::doTest);
+  }
+
+  // PY-22971
+  public void testOverloadsAndImplementationsInClass() {
+    runWithLanguageLevel(LanguageLevel.PYTHON36, this::doTest);
+  }
+
+  // PY-22971
+  public void testTopLevelOverloadImplementationOverloadImplementation() {
+    runWithLanguageLevel(LanguageLevel.PYTHON36, this::doTest);
+  }
+
+  // PY-22971
+  public void testOverloadImplementationOverloadImplementationInClass() {
+    runWithLanguageLevel(LanguageLevel.PYTHON36, this::doTest);
+  }
+
   private void doTest() {
     final String path = "inspections/PyRedeclarationInspection/" + getTestName(true) + ".py";