Lambda to reference: not-null types are now preferred for platform type receivers #KT-14394 Fixed

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

@@ -17,7 +17,6 @@
 package org.jetbrains.kotlin.idea.intentions
 
 import com.intellij.openapi.editor.Editor
-import com.intellij.openapi.util.TextRange
 import org.jetbrains.kotlin.builtins.getReturnTypeFromFunctionType
 import org.jetbrains.kotlin.builtins.isExtensionFunctionType
 import org.jetbrains.kotlin.builtins.isFunctionType
@@ -30,9 +29,6 @@ import org.jetbrains.kotlin.idea.inspections.IntentionBasedInspection
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.idea.util.approximateFlexibleTypes
 import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.endOffset
-import org.jetbrains.kotlin.psi.psiUtil.getStartOffsetIn
-import org.jetbrains.kotlin.psi.psiUtil.startOffset
 import org.jetbrains.kotlin.resolve.BindingContext.REFERENCE_TARGET
 import org.jetbrains.kotlin.resolve.descriptorUtil.hasDefaultValue
 import org.jetbrains.kotlin.synthetic.SyntheticJavaPropertyDescriptor
@@ -227,7 +223,7 @@ class ConvertLambdaToReferenceIntention : SelfTargetingOffsetIndependentIntentio
                     val context = receiver.analyze()
                     val receiverDescriptor = context[REFERENCE_TARGET, receiver] as? ParameterDescriptor ?: return null
                     val originalReceiverType = receiverDescriptor.type
-                    val receiverType = originalReceiverType.approximateFlexibleTypes()
+                    val receiverType = originalReceiverType.approximateFlexibleTypes(preferNotNull = true)
                     if (shortTypes) {
                         "${IdeDescriptorRenderers.SOURCE_CODE_SHORT_NAMES_IN_TYPES.renderType(receiverType)}::$selectorReferenceName"
                     }

idea/testData/intentions/convertLambdaToReference/platformType.kt

@@ -0,0 +1,4 @@
+// WITH_RUNTIME
+
+val y = java.lang.String.valueOf(42)
+val x = y.let { <caret>it.capitalize() }

idea/testData/intentions/convertLambdaToReference/platformType.kt.after

@@ -0,0 +1,4 @@
+// WITH_RUNTIME
+
+val y = java.lang.String.valueOf(42)
+val x = y.let(String::capitalize)

idea/testData/intentions/convertLambdaToReference/typeFromJava.kt.after

@@ -2,5 +2,5 @@
 // See KT-13411
 
 fun use() {
-    B.text.map(Any?::toString)
+    B.text.map(Any::toString)
 }

idea/testData/intentions/convertLambdaToReference/typeFromJavaFlexibleRecursive.kt.after

@@ -3,5 +3,5 @@
 
 fun use() {
     val text = B.text
-    text.map(MutableList<Any>?::toString)
+    text.map(MutableList<Any>::toString)
 }

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

@@ -4135,6 +4135,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("platformType.kt")
+        public void testPlatformType() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/convertLambdaToReference/platformType.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("receiverParameter.kt")
         public void testReceiverParameter() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/convertLambdaToReference/receiverParameter.kt");