Fix "move suspicious reference into parentheses" for functional types

So #KT-21743 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/MoveSuspiciousCallableReferenceIntoParenthesesInspection.kt

@@ -13,9 +13,11 @@ import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.builtins.getReturnTypeFromFunctionType
 import org.jetbrains.kotlin.builtins.isBuiltinFunctionalType
 import org.jetbrains.kotlin.builtins.isBuiltinFunctionalTypeOrSubtype
+import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
 import org.jetbrains.kotlin.idea.intentions.ConvertLambdaToReferenceIntention
+import org.jetbrains.kotlin.idea.intentions.getCallableDescriptor
 import org.jetbrains.kotlin.psi.KtCallableReferenceExpression
 import org.jetbrains.kotlin.psi.KtLambdaExpression
 import org.jetbrains.kotlin.psi.ValueArgument
@@ -33,7 +35,7 @@ class MoveSuspiciousCallableReferenceIntoParenthesesInspection : AbstractKotlinI
                 val parentResolvedCall = lambdaExpression.getParentResolvedCall(context)
                 if (parentResolvedCall != null) {
                     val originalParameterDescriptor =
-                            parentResolvedCall.getParameterForArgument(lambdaExpression.parent as? ValueArgument)?.original
+                        parentResolvedCall.getParameterForArgument(lambdaExpression.parent as? ValueArgument)?.original
                     if (originalParameterDescriptor != null) {
                         val expectedType = originalParameterDescriptor.type
                         if (expectedType.isBuiltinFunctionalType) {
@@ -43,10 +45,10 @@ class MoveSuspiciousCallableReferenceIntoParenthesesInspection : AbstractKotlinI
                     }
                 }
                 holder.registerProblem(
-                        lambdaExpression,
-                        "Suspicious callable reference as the only lambda element",
-                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                        IntentionWrapper(MoveIntoParenthesesIntention(), lambdaExpression.containingFile)
+                    lambdaExpression,
+                    "Suspicious callable reference as the only lambda element",
+                    ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                    IntentionWrapper(MoveIntoParenthesesIntention(), lambdaExpression.containingFile)
                 )
 
             }
@@ -54,15 +56,25 @@ class MoveSuspiciousCallableReferenceIntoParenthesesInspection : AbstractKotlinI
     }
 
     class MoveIntoParenthesesIntention : ConvertLambdaToReferenceIntention(
-            "Move suspicious callable reference into parentheses '()'"
+        "Move suspicious callable reference into parentheses '()'"
     ) {
         override fun buildReferenceText(element: KtLambdaExpression): String? {
             val callableReferenceExpression =
-                    element.bodyExpression?.statements?.singleOrNull() as? KtCallableReferenceExpression ?: return null
+                element.bodyExpression?.statements?.singleOrNull() as? KtCallableReferenceExpression ?: return null
             val callableReference = callableReferenceExpression.callableReference
-            val resolvedCall = callableReference.resolveToCall(BodyResolveMode.FULL)
-            val receiverValue = resolvedCall?.let { it.extensionReceiver ?: it.dispatchReceiver }
-            return (receiverValue?.let { "${it.type}" } ?: "") + "::${callableReference.text}"
+            val receiverExpression = callableReferenceExpression.receiverExpression
+            val receiver = if (receiverExpression == null) {
+                ""
+            } else {
+                val descriptor = receiverExpression.getCallableDescriptor()
+                if (descriptor == null || descriptor is ValueParameterDescriptor)
+                    callableReference.resolveToCall(BodyResolveMode.FULL)
+                        ?.let { it.extensionReceiver ?: it.dispatchReceiver }
+                        ?.let { "${it.type}" } ?: ""
+                else
+                    receiverExpression.text
+            }
+            return "$receiver::${callableReference.text}"
         }
 
         override fun isApplicableTo(element: KtLambdaExpression) = true

idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/explicitThisReceiver.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+class Test {
+    fun function(s: String): Boolean = true
+    fun test() {
+        "".let {<caret> this::function }
+    }
+}

idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/explicitThisReceiver.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+class Test {
+    fun function(s: String): Boolean = true
+    fun test() {
+        "".let(this::function)
+    }
+}

idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/implicitThisReceiver.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+class Test {
+    fun function(s: String): Boolean = true
+    fun test() {
+        "".let {<caret> ::function }
+    }
+}

idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/implicitThisReceiver.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+class Test {
+    fun function(s: String): Boolean = true
+    fun test() {
+        "".let(::function)
+    }
+}

idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/variableReceiver.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+class Test {
+    val lambda = { s: String -> true }
+    fun test() {
+        "".let {<caret> lambda::invoke }
+    }
+}

idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/variableReceiver.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+class Test {
+    val lambda = { s: String -> true }
+    fun test() {
+        "".let(lambda::invoke)
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -2301,6 +2301,18 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("explicitThisReceiver.kt")
+        public void testExplicitThisReceiver() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/explicitThisReceiver.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("implicitThisReceiver.kt")
+        public void testImplicitThisReceiver() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/implicitThisReceiver.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("it.kt")
         public void testIt() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/it.kt");
@@ -2348,6 +2360,12 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/parameter2.kt");
             doTest(fileName);
         }
+
+        @TestMetadata("variableReceiver.kt")
+        public void testVariableReceiver() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/moveSuspiciousCallableReferenceIntoParentheses/variableReceiver.kt");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/inspectionsLocal/nullChecksToSafeCall")