Fixed assignment balance inspection for sliced tuples (PY-6315)

python/src/com/jetbrains/python/psi/PySliceExpression.java

@@ -1,11 +1,13 @@
 package com.jetbrains.python.psi;
 
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
  * @author yole
  */
 public interface PySliceExpression extends PyExpression {
+  @NotNull
   PyExpression getOperand();
 
   @Nullable

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

@@ -2,11 +2,11 @@ package com.jetbrains.python.psi.impl;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.psi.util.PsiTreeUtil;
-import com.jetbrains.python.PyElementTypes;
 import com.jetbrains.python.PythonDialectsTokenSetProvider;
 import com.jetbrains.python.psi.PyExpression;
 import com.jetbrains.python.psi.PySliceExpression;
 import com.jetbrains.python.psi.PySliceItem;
+import com.jetbrains.python.psi.types.PyTupleType;
 import com.jetbrains.python.psi.types.PyType;
 import com.jetbrains.python.psi.types.TypeEvalContext;
 import org.jetbrains.annotations.NotNull;
@@ -20,15 +20,25 @@ public class PySliceExpressionImpl extends PyElementImpl implements PySliceExpre
     super(astNode);
   }
 
+  @Nullable
+  @Override
   public PyType getType(@NotNull TypeEvalContext context) {
-    return context.getType(getOperand());
+    final PyType type = context.getType(getOperand());
+    // TODO: Currently we don't evaluate the static range of the slice, so we have to return a generic tuple type without elements
+    if (type instanceof PyTupleType) {
+      return PyBuiltinCache.getInstance(this).getTupleType();
+    }
+    return type;
   }
 
+  @NotNull
+  @Override
   public PyExpression getOperand() {
     return childToPsiNotNull(PythonDialectsTokenSetProvider.INSTANCE.getExpressionTokens(), 0);
   }
 
   @Nullable
+  @Override
   public PySliceItem getSliceItem() {
     return PsiTreeUtil.getChildOfType(this, PySliceItem.class);
   }

python/testData/inspections/PyTupleAssignmentBalanceInspection3/test.py

@@ -12,4 +12,10 @@ a, b = <warning descr="Too many values to unpack">c</warning>
 a, b = <warning descr="Too many values to unpack">[1, 2, 3]</warning>
 a, b = <warning descr="Too many values to unpack">'str'</warning>
 a, b = <warning descr="Too many values to unpack">{1, 2, 3}</warning>
-a, b = <warning descr="Too many values to unpack">{1:2, 2: 3, 3:4}</warning>
+a, b = <warning descr="Too many values to unpack">{1:2, 2: 3, 3:4}</warning>
+
+# PY-6315
+def test_tuple_slice():
+    def f():
+        return 1, 2, 3
+    x, y = f()[:2]