KT-11104 extra : name validator introduced for wrap with safe let call

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

@@ -21,6 +21,8 @@ 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.core.KotlinNameSuggester
+import org.jetbrains.kotlin.idea.core.NewDeclarationNameValidator
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.types.TypeUtils
@@ -38,8 +40,13 @@ class WrapWithSafeLetCallFix(
     override fun invoke(project: Project, editor: Editor?, file: KtFile) {
         val factory = KtPsiFactory(element)
         val nullableText = nullableExpression.text
-        nullableExpression.replace(factory.createExpression("it"))
-        val wrapped = factory.createExpressionByPattern("$0?.let { $1 }", nullableText, element.text)
+        val validator = NewDeclarationNameValidator(element, nullableExpression, NewDeclarationNameValidator.Target.VARIABLES)
+        val name = KotlinNameSuggester.suggestNameByName("it", validator)
+        nullableExpression.replace(factory.createExpression(name))
+        val wrapped = when (name) {
+            "it" -> factory.createExpressionByPattern("$0?.let { $1 }", nullableText, element)
+            else -> factory.createExpressionByPattern("$0?.let { $1 -> $2 }", nullableText, name, element)
+        }
         element.replace(wrapped)
     }
 

idea/testData/quickfix/wrapWithSafeLetCall/insideLet.kt

@@ -0,0 +1,8 @@
+// "Wrap with '?.let { ... }' call" "true"
+// WITH_RUNTIME
+
+fun foo(x: String?, y: String) {
+    y.let { bar(<caret>x, it) }
+}
+
+fun bar(s: String, t: String) = s.hashCode() + t.hashCode()

idea/testData/quickfix/wrapWithSafeLetCall/insideLet.kt.after

@@ -0,0 +1,8 @@
+// "Wrap with '?.let { ... }' call" "true"
+// WITH_RUNTIME
+
+fun foo(x: String?, y: String) {
+    y.let { x?.let { it1 -> bar(it1, it) } }
+}
+
+fun bar(s: String, t: String) = s.hashCode() + t.hashCode()

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

@@ -8788,6 +8788,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("insideLet.kt")
+        public void testInsideLet() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/wrapWithSafeLetCall/insideLet.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("invokeFuncUnsafe.kt")
         public void testInvokeFuncUnsafe() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/wrapWithSafeLetCall/invokeFuncUnsafe.kt");