ConvertLambdaToReference refactoring

Intention is not registered now; inspection is enabled by default now,
 but has highlight level of "No highlighting"
Inspection does not depend on text length now

So #KT-14335 Fixed

idea/src/META-INF/plugin.xml

@@ -1385,11 +1385,6 @@
       <category>Kotlin</category>
     </intentionAction>
 
-    <intentionAction>
-      <className>org.jetbrains.kotlin.idea.intentions.ConvertLambdaToReferenceIntention</className>
-      <category>Kotlin</category>
-    </intentionAction>
-
     <intentionAction>
       <className>org.jetbrains.kotlin.idea.intentions.ConvertReferenceToLambdaIntention</className>
       <category>Kotlin</category>
@@ -1953,8 +1948,8 @@
     <localInspection implementationClass="org.jetbrains.kotlin.idea.intentions.ConvertLambdaToReferenceInspection"
                      displayName="Can be replaced with function reference"
                      groupName="Kotlin"
-                     enabledByDefault="false"
-                     level="INFO"
+                     enabledByDefault="true"
+                     level="INFORMATION"
                      language="kotlin"
     />
 

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

@@ -40,12 +40,7 @@ import org.jetbrains.kotlin.types.isError
 import org.jetbrains.kotlin.types.typeUtil.isTypeParameter
 import org.jetbrains.kotlin.types.typeUtil.isUnit
 
-class ConvertLambdaToReferenceInspection : IntentionBasedInspection<KtLambdaExpression>(
-        ConvertLambdaToReferenceIntention::class,
-        { it -> ConvertLambdaToReferenceIntention.shouldSuggestToConvert(it) }
-) {
-    override fun inspectionTarget(element: KtLambdaExpression) = element.bodyExpression?.statements?.singleOrNull()
-}
+class ConvertLambdaToReferenceInspection : IntentionBasedInspection<KtLambdaExpression>(ConvertLambdaToReferenceIntention::class)
 
 open class ConvertLambdaToReferenceIntention(text: String) :
         SelfTargetingOffsetIndependentIntention<KtLambdaExpression>(KtLambdaExpression::class.java, text) {
@@ -219,10 +214,6 @@ open class ConvertLambdaToReferenceIntention(text: String) :
     }
 
     companion object {
-        internal fun shouldSuggestToConvert(element: KtLambdaExpression): Boolean {
-            val referenceName = buildReferenceText(lambdaExpression = element, shortTypes = true) ?: return false
-            return referenceName.length < element.text.length
-        }
 
         private fun buildReferenceText(lambdaExpression: KtLambdaExpression, shortTypes: Boolean): String? {
             val singleStatement = lambdaExpression.singleStatementOrNull()

idea/testData/inspections/convertLambdaToReference/inspectionData/expected.xml

@@ -9,7 +9,15 @@
     </problem>
     <problem>
         <file>test.kt</file>
-        <line>14</line>
+        <line>9</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Can be replaced with function reference</problem_class>
+        <description>Convert lambda to reference</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>13</line>
         <module>light_idea_test_case</module>
         <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
         <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Can be replaced with function reference</problem_class>

idea/testData/inspections/convertLambdaToReference/test.kt

@@ -4,7 +4,7 @@
 class TheirWrapper(val x: Int)
 val x = { y: Int -> TheirWrapper(y) }
 
-// Should not suggest to convert (too long reference)
+// Should suggest to convert despite of too long reference
 fun foo(arg: TheirWrapper, convert: (TheirWrapper) -> String) = convert(arg)
 val y = foo(TheirWrapper(42)) { it.toString() }