KT-7194 No completion for member extension function inside itself

#KT-7194 Fixed

idea/ide-common/src/org/jetbrains/kotlin/idea/codeInsight/ReferenceVariantsHelper.kt

@@ -126,12 +126,14 @@ public class ReferenceVariantsHelper(
 
             // process extensions and non-instance members
             for (descriptor in resolutionScope.getDescriptorsFiltered(kindFilter, nameFilter)) {
-                if (descriptor is CallableDescriptor && descriptor.getDispatchReceiverParameter() != null) continue // should already be processed via implicit receivers
-
                 if (descriptor is CallableDescriptor && descriptor.getExtensionReceiverParameter() != null) {
-                    descriptorsSet.addAll(descriptor.substituteExtensionIfCallable(receiverValues, context, dataFlowInfo, CallType.NORMAL))
+                    val dispatchReceiver = descriptor.getDispatchReceiverParameter()
+                    if (dispatchReceiver == null || dispatchReceiver in receivers) {
+                        descriptorsSet.addAll(descriptor.substituteExtensionIfCallable(receiverValues, context, dataFlowInfo, CallType.NORMAL))
+                    }
                 }
                 else {
+                    if (descriptor is CallableDescriptor && descriptor.getDispatchReceiverParameter() != null) continue // should already be processed via implicit receivers
                     descriptorsSet.add(descriptor)
                 }
             }

idea/testData/completion/basic/common/extensions/MemberExtensionsFromMemberExtension.kt

@@ -0,0 +1,20 @@
+class C {
+    fun String.extFun() {
+        <caret>
+    }
+
+    fun String.otherExtFun() { }
+    fun Int.wrongExtFun() { }
+
+    companion object {
+        fun String.companionExtFun() { }
+    }
+}
+
+fun String.nonMemberExtFun() {}
+
+// EXIST: extFun
+// EXIST: otherExtFun
+// ABSENT: wrongExtFun
+// EXIST: nonMemberExtFun
+// EXIST: companionExtFun

idea/testData/completion/basic/common/extensions/NoMemberExtensionsFromCompanionObject.kt

@@ -0,0 +1,14 @@
+class C {
+    fun String.extFun() { }
+
+    companion object {
+        fun String.foo() {
+            <caret>
+        }
+    }
+}
+
+fun String.nonMemberExtFun() {}
+
+// EXIST: nonMemberExtFun
+// ABSENT: extFun

idea/tests/org/jetbrains/kotlin/completion/JSBasicCompletionTestGenerated.java

@@ -1242,6 +1242,12 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
                 doTest(fileName);
             }
 
+            @TestMetadata("MemberExtensionsFromMemberExtension.kt")
+            public void testMemberExtensionsFromMemberExtension() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/MemberExtensionsFromMemberExtension.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("NoDuplicatedMethodForSmartCast.kt")
             public void testNoDuplicatedMethodForSmartCast() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/NoDuplicatedMethodForSmartCast.kt");
@@ -1254,6 +1260,12 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
                 doTest(fileName);
             }
 
+            @TestMetadata("NoMemberExtensionsFromCompanionObject.kt")
+            public void testNoMemberExtensionsFromCompanionObject() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/NoMemberExtensionsFromCompanionObject.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("WrongExplicitReceiver.kt")
             public void testWrongExplicitReceiver() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/WrongExplicitReceiver.kt");

idea/tests/org/jetbrains/kotlin/completion/JvmBasicCompletionTestGenerated.java

@@ -1242,6 +1242,12 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
                 doTest(fileName);
             }
 
+            @TestMetadata("MemberExtensionsFromMemberExtension.kt")
+            public void testMemberExtensionsFromMemberExtension() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/MemberExtensionsFromMemberExtension.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("NoDuplicatedMethodForSmartCast.kt")
             public void testNoDuplicatedMethodForSmartCast() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/NoDuplicatedMethodForSmartCast.kt");
@@ -1254,6 +1260,12 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
                 doTest(fileName);
             }
 
+            @TestMetadata("NoMemberExtensionsFromCompanionObject.kt")
+            public void testNoMemberExtensionsFromCompanionObject() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/NoMemberExtensionsFromCompanionObject.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("WrongExplicitReceiver.kt")
             public void testWrongExplicitReceiver() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/extensions/WrongExplicitReceiver.kt");