Fix WrapWithSafeLetCallFix ignore extension method

Related to KT-17726

idea/src/org/jetbrains/kotlin/idea/quickfix/WrapWithSafeLetCallFix.kt

@@ -21,12 +21,14 @@ import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.diagnostics.Diagnostic
 import org.jetbrains.kotlin.diagnostics.Errors
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.idea.core.NewDeclarationNameValidator
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 import org.jetbrains.kotlin.psi.psiUtil.getLastParentOfTypeInRow
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.types.typeUtil.isNullabilityMismatch
 
 class WrapWithSafeLetCallFix(
@@ -57,6 +59,12 @@ class WrapWithSafeLetCallFix(
     object UnsafeFactory : KotlinSingleIntentionActionFactory() {
         override fun createAction(diagnostic: Diagnostic): IntentionAction? {
             val element = diagnostic.psiElement
+
+            if (element is KtNameReferenceExpression) {
+                val resolvedCall = element.getResolvedCall(element.analyze())
+                if (resolvedCall?.call?.callType != Call.CallType.INVOKE) return null
+            }
+
             val expression = element.getParentOfType<KtExpression>(true) ?: return null
 
             val parent = element.parent

idea/testData/quickfix/replaceWithSafeCall/noReplaceWithSafeCallForImplicitReceiver.kt

@@ -2,7 +2,6 @@
 // ACTION: Add non-null asserted (!!) call
 // ACTION: Convert to expression body
 // ACTION: Replace with safe (this?.) call
-// ACTION: Wrap with '?.let { ... }' call
 // ERROR: Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type A?
 
 class A {

idea/testData/quickfix/wrapWithSafeLetCall/extensionMethod.kt

@@ -0,0 +1,10 @@
+// "Wrap with '?.let { ... }' call" "false"
+// WITH_RUNTIME
+// ACTION: Add non-null asserted (!!) call
+// ACTION: Introduce local variable
+// ACTION: Replace with safe (this?.) call
+// ERROR: Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type String?
+
+fun String?.foo() {
+    toLowerCase<caret>()
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -11243,6 +11243,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("extensionMethod.kt")
+        public void testExtensionMethod() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/wrapWithSafeLetCall/extensionMethod.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("insideLet.kt")
         public void testInsideLet() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/wrapWithSafeLetCall/insideLet.kt");