Lambda --> reference: correct handling of parameter-less function

Issue #KT-15556 Fixed

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

@@ -99,8 +99,8 @@ class ConvertLambdaToReferenceIntention : SelfTargetingOffsetIndependentIntentio
         val lambdaParameterAsExplicitReceiver = explicitReceiverDescriptor != null &&
                                                 explicitReceiverDescriptor == lambdaValueParameterDescriptors.firstOrNull()
         val explicitReceiverShift = if (lambdaParameterAsExplicitReceiver) 1 else 0
-        val lambdaParametersCount =
+
-                if (lambdaExpression.functionLiteral.hasParameterSpecification()) lambdaExpression.valueParameters.size else 1
+        val lambdaParametersCount = lambdaValueParameterDescriptors.size
         if (lambdaParametersCount != callableArgumentsCount + explicitReceiverShift) return false
 
         if (explicitReceiver != null && explicitReceiverDescriptor != null && lambdaParameterAsExplicitReceiver) {

idea/testData/intentions/convertLambdaToReference/defaultConstructor.kt

@@ -0,0 +1,5 @@
+class Foo
+fun usage(f: () -> Foo) {}
+fun test() {
+    usage {<caret> Foo() }
+}

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

@@ -0,0 +1,5 @@
+class Foo
+fun usage(f: () -> Foo) {}
+fun test() {
+    usage(::Foo)
+}

idea/testData/intentions/convertLambdaToReference/nestedLambdaWithReceiver.kt

@@ -1,4 +1,4 @@
-// IS_APPLICABLE: false
+// IS_APPLICABLE: true
 // WITH_RUNTIME
 
 fun foo() {

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

@@ -0,0 +1,9 @@
+// IS_APPLICABLE: true
+// WITH_RUNTIME
+
+fun foo() {
+    listOf(1).forEach { run(it::bar) }
+}
+
+fun Int.bar() {
+}

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

@@ -4340,6 +4340,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("defaultConstructor.kt")
+        public void testDefaultConstructor() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/convertLambdaToReference/defaultConstructor.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("defaultNamed.kt")
         public void testDefaultNamed() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/convertLambdaToReference/defaultNamed.kt");