Extraction Engine: Forbid extraction of non-singleton qualifiers

#KT-8297 Fixed

idea/src/org/jetbrains/kotlin/idea/codeInsight/CodeInsightUtils.java

@@ -27,8 +27,14 @@ import com.intellij.refactoring.util.CommonRefactoringUtil;
 import com.intellij.util.text.CharArrayUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.kotlin.descriptors.ClassDescriptor;
+import org.jetbrains.kotlin.descriptors.ClassKind;
+import org.jetbrains.kotlin.descriptors.ClassifierDescriptor;
+import org.jetbrains.kotlin.idea.caches.resolve.ResolvePackage;
 import org.jetbrains.kotlin.lexer.JetTokens;
 import org.jetbrains.kotlin.psi.*;
+import org.jetbrains.kotlin.resolve.BindingContext;
+import org.jetbrains.kotlin.resolve.scopes.receivers.Qualifier;
 import org.jetbrains.kotlin.types.JetType;
 
 import java.util.ArrayList;
@@ -65,7 +71,18 @@ public class CodeInsightUtils {
                 }
             }
         }
-        return (JetExpression) element;
+
+        JetExpression expression = (JetExpression) element;
+
+        BindingContext context = ResolvePackage.analyze(expression);
+
+        Qualifier qualifier = context.get(BindingContext.QUALIFIER, expression);
+        if (qualifier != null) {
+            ClassifierDescriptor classifier = qualifier.getClassifier();
+            if (!(classifier instanceof ClassDescriptor) || ((ClassDescriptor) classifier).getKind() != ClassKind.OBJECT) return null;
+        }
+
+        return expression;
     }
 
     @NotNull

idea/testData/refactoring/extractFunction/basic/classQualifier.kt

@@ -0,0 +1,11 @@
+class A {
+    companion object {
+        fun foo() {
+
+        }
+    }
+}
+
+fun bar() {
+    <selection>A</selection>.foo()
+}

idea/testData/refactoring/extractFunction/basic/classQualifier.kt.conflicts

@@ -0,0 +1 @@
+Cannot perform refactoring without an expression

idea/testData/refactoring/extractFunction/basic/enumQualifier.kt

@@ -0,0 +1,7 @@
+enum class E {
+    A, B, C
+}
+
+fun bar() {
+    val t = <selection>E</selection>.A
+}

idea/testData/refactoring/extractFunction/basic/enumQualifier.kt.conflicts

@@ -0,0 +1 @@
+Cannot perform refactoring without an expression

idea/testData/refactoring/extractFunction/basic/objectQualifier.kt

@@ -0,0 +1,9 @@
+object A {
+    fun foo() {
+
+    }
+}
+
+fun bar() {
+    <selection>A</selection>.foo()
+}

idea/testData/refactoring/extractFunction/basic/objectQualifier.kt.after

@@ -0,0 +1,11 @@
+object A {
+    fun foo() {
+
+    }
+}
+
+fun bar() {
+    a().foo()
+}
+
+private fun a() = A

idea/testData/refactoring/extractFunction/basic/packageQualifier.kt

@@ -0,0 +1,9 @@
+package p
+
+fun foo() {
+
+}
+
+fun bar() {
+    <selection>p</selection>.foo()
+}

idea/testData/refactoring/extractFunction/basic/packageQualifier.kt.conflicts

@@ -0,0 +1 @@
+Cannot perform refactoring without an expression

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/JetExtractionTestGenerated.java

@@ -456,6 +456,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                 doExtractFunctionTest(fileName);
             }
 
+            @TestMetadata("classQualifier.kt")
+            public void testClassQualifier() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/classQualifier.kt");
+                doExtractFunctionTest(fileName);
+            }
+
             @TestMetadata("convertBinaryExpression.kt")
             public void testConvertBinaryExpression() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/convertBinaryExpression.kt");
@@ -480,6 +486,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                 doExtractFunctionTest(fileName);
             }
 
+            @TestMetadata("enumQualifier.kt")
+            public void testEnumQualifier() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/enumQualifier.kt");
+                doExtractFunctionTest(fileName);
+            }
+
             @TestMetadata("extensionFunForArray.kt")
             public void testExtensionFunForArray() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/extensionFunForArray.kt");
@@ -630,6 +642,18 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                 doExtractFunctionTest(fileName);
             }
 
+            @TestMetadata("objectQualifier.kt")
+            public void testObjectQualifier() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/objectQualifier.kt");
+                doExtractFunctionTest(fileName);
+            }
+
+            @TestMetadata("packageQualifier.kt")
+            public void testPackageQualifier() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/packageQualifier.kt");
+                doExtractFunctionTest(fileName);
+            }
+
             @TestMetadata("privateMemberInClassObject.kt")
             public void testPrivateMemberInClassObject() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/basic/privateMemberInClassObject.kt");