KT-2484 Type inferred for function literal is (...) -> Int instead of (...) -> Unit, when function literal parameter is explicit

#KT-2484 fixed

compiler/testData/diagnostics/tests/inference/regressions/kt2484.kt

@@ -0,0 +1,23 @@
+//KT-2484 Type inferred for function literal is (...) -> Int instead of (...) -> Unit, when function literal parameter is explicit 
+
+package a
+//+JDK
+import java.util.List
+
+fun <T> Array<T>.forEach(operation: (T) -> Unit) : Unit = for (element in this) operation(element)
+
+fun bar(operation: (String) -> Unit) = operation("")
+
+fun main(args: Array<String>) {
+    args.forEach { (a : String) : Unit -> a.length } // Type mismatch: (String) -> Unit required, (String) -> Int found
+    args.forEach { (a) : Unit -> a.length } // Type mismatch: (String) -> Unit required, (String) -> Int found
+    args.forEach { (a : String) -> a.length } // Type mismatch: (String) -> Unit required, (String) -> Int found
+    args.forEach { a -> a.length } // Type mismatch: (String) -> Unit required, (String) -> Int found
+    args.forEach { it.length }     // This works!
+
+    bar { (a: String) : Unit -> a.length }
+    bar { (a) : Unit -> a.length }
+    bar { (a: String) -> a.length }
+    bar { a -> a.length }
+    bar { it.length }
+}