False positive removed in replace single line let intention #KT-14791 Fixed

idea/src/org/jetbrains/kotlin/idea/intentions/ReplaceSingleLineLetIntention.kt

@@ -94,7 +94,7 @@ class ReplaceSingleLineLetIntention : SelfTargetingOffsetIndependentIntention<Kt
         val bodyExpression = lambdaExpression.bodyExpression?.children?.singleOrNull() ?: return false
 
         return when (bodyExpression) {
-            is KtBinaryExpression -> bodyExpression.isApplicable(parameterName)
+            is KtBinaryExpression -> element.parent !is KtSafeQualifiedExpression && bodyExpression.isApplicable(parameterName)
             is KtDotQualifiedExpression -> bodyExpression.isApplicable(parameterName)
             else -> false
         }
@@ -105,6 +105,7 @@ class ReplaceSingleLineLetIntention : SelfTargetingOffsetIndependentIntention<Kt
         when (left) {
             is KtNameReferenceExpression -> if (left.text != parameterName) return false
             is KtDotQualifiedExpression -> if (!left.isApplicable(parameterName)) return false
+            else -> return false
         }
 
         val right = right ?: return false

idea/testData/intentions/replaceSingleLineLetIntention/assignment.kt

@@ -0,0 +1,8 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+fun withAssign(arg: String?): String {
+    var result: String = ""
+    arg?.let<caret> { result = it }
+    return result
+}

idea/testData/intentions/replaceSingleLineLetIntention/comparisons.kt

@@ -0,0 +1,4 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+fun isAlphaOrBeta(str: String) = str.let<caret> { it == "Alpha" || it == "Beta" }

idea/testData/intentions/replaceSingleLineLetIntention/plusNullable.kt

@@ -0,0 +1,4 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+fun plusNullable(arg: String?) = arg?.let<caret> { it + "#" } ?: ""

idea/testData/intentions/replaceSingleLineLetIntention/smartCastInBody.kt

@@ -0,0 +1,15 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+interface A
+
+interface B : A {
+    val bar: Any?
+}
+
+class Foo {
+    private val a: A = object : A {}
+
+    val isB: Boolean
+        get() = a.let<caret> { it is B && it.bar != null }
+}

idea/testData/intentions/replaceSingleLineLetIntention/typeChecks.kt

@@ -0,0 +1,9 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+interface Base
+
+class A : Base
+class B : Base
+
+fun isAB(arg: Base) = arg.let<caret> { it is A || it is B }

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -11799,6 +11799,18 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/intentions/replaceSingleLineLetIntention"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
         }
 
+        @TestMetadata("assignment.kt")
+        public void testAssignment() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/assignment.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("comparisons.kt")
+        public void testComparisons() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/comparisons.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("lambdaWithBinaryExpression.kt")
         public void testLambdaWithBinaryExpression() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt");
@@ -11949,6 +11961,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("plusNullable.kt")
+        public void testPlusNullable() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/plusNullable.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("receiverWithLambda.kt")
         public void testReceiverWithLambda() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/receiverWithLambda.kt");
@@ -11967,6 +11985,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("smartCastInBody.kt")
+        public void testSmartCastInBody() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/smartCastInBody.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("this.kt")
         public void testThis() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/this.kt");
@@ -11978,6 +12002,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/thisShort.kt");
             doTest(fileName);
         }
+
+        @TestMetadata("typeChecks.kt")
+        public void testTypeChecks() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/typeChecks.kt");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/intentions/replaceSizeCheckWithIsNotEmpty")