Fixing failed tests: do not report anything on casts that can never succeed

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java

@@ -221,21 +221,21 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
         if (!CastDiagnosticsUtil.isCastPossible(actualType, targetType, platformToKotlinClassMap)) {
             context.trace.report(CAST_NEVER_SUCCEEDS.on(expression.getOperationReference()));
         }
-
-        JetTypeChecker typeChecker = JetTypeChecker.INSTANCE;
-        if (!typeChecker.isSubtypeOf(targetType, actualType)) {
-            if (typeChecker.isSubtypeOf(actualType, targetType)) {
-                context.trace.report(USELESS_CAST_STATIC_ASSERT_IS_FINE.on(expression.getOperationReference()));
-            }
-        }
         else {
+            JetTypeChecker typeChecker = JetTypeChecker.INSTANCE;
+            // Upcast?
             if (typeChecker.isSubtypeOf(actualType, targetType)) {
-                context.trace.report(USELESS_CAST.on(expression.getOperationReference()));
-            }
-            else {
-                if (CastDiagnosticsUtil.isCastErased(actualType, targetType, typeChecker)) {
-                    context.trace.report(Errors.UNCHECKED_CAST.on(expression, actualType, targetType));
+                if (!typeChecker.isSubtypeOf(targetType, actualType)) {
+                    // proper upcast: String as Any
+                    context.trace.report(USELESS_CAST_STATIC_ASSERT_IS_FINE.on(expression.getOperationReference()));
                 }
+                else {
+                    // cast to itself: String as String
+                    context.trace.report(USELESS_CAST.on(expression.getOperationReference()));
+                }
+            }
+            else if (CastDiagnosticsUtil.isCastErased(actualType, targetType, typeChecker)) {
+                context.trace.report(Errors.UNCHECKED_CAST.on(expression, actualType, targetType));
             }
         }
     }

compiler/testData/diagnostics/tests/ResolveToJava.kt

@@ -29,7 +29,7 @@ fun test(<!UNUSED_PARAMETER!>l<!> : <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.util
   <!UNRESOLVED_REFERENCE!>List<!><Int>
 
 
-  val <!UNUSED_VARIABLE!>o<!> = "sdf" <!CAST_NEVER_SUCCEEDS!>as<!> <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>Object<!>
+  val <!UNUSED_VARIABLE!>o<!> = "sdf" as <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>Object<!>
 
   try {
     // ...

compiler/testData/diagnostics/tests/cast/AsErasedError.kt

@@ -1,2 +1,2 @@
 
-fun ff(c: MutableCollection<String>) = c <!CAST_NEVER_SUCCEEDS!>as<!> MutableList<Int>
+fun ff(c: MutableCollection<String>) = <!UNCHECKED_CAST!>c as MutableList<Int><!>

compiler/testData/diagnostics/tests/delegatedProperty/inference/differentDelegatedExpressions.kt

@@ -23,7 +23,7 @@ class MyProperty<R, T> {
 
     public fun get(thisRef: R, desc: PropertyMetadata): T {
         println("get $thisRef ${desc.name}")
-        return null <!CAST_NEVER_SUCCEEDS!>as<!> T
+        return null as T
     }
 
     public fun set(thisRef: R, desc: PropertyMetadata, value: T) {

compiler/testData/diagnostics/tests/nullableTypes/uselessElvis.kt

@@ -1,11 +1,11 @@
 // For KT-3491
 
 fun <T: Any?> test1(t: Any?): Any {
-    return t as T ?: ""
+    return <!UNCHECKED_CAST!>t as T<!> ?: ""
 }
 
 fun <T: Any> test2(t: Any?): Any {
-    return <!USELESS_ELVIS!>t as T<!> ?: ""
+    return <!UNCHECKED_CAST, USELESS_ELVIS!>t as T<!> ?: ""
 }
 
 fun <T: Any?> test3(t: Any?): Any {

compiler/testData/diagnostics/tests/regressions/kt307.kt

@@ -6,6 +6,6 @@ open class AL {
 
 trait ALE<T> : AL {
 fun getOrNull(index: Int, value: T) : T {
-return get(index) as? T ?: value
-}
+return <!UNCHECKED_CAST!>get(index) as? T<!> ?: value
 }
+}

compiler/testData/diagnostics/tests/regressions/kt398.kt

@@ -1,11 +1,11 @@
 // KT-398 Internal error when property initializes with function
 
 class X<T>() {
-    val check = { (a : Any) -> a is T }
+    val check = { (a : Any) -> a is <!CANNOT_CHECK_FOR_ERASED!>T<!> }
 }
 
 fun box() : String {
     if(X<String>().check(10)) return "fail"
     if(!X<String>().check("lala")) return "fail"
     return "OK"
-}
+}

compiler/testData/diagnostics/tests/regressions/kt399.kt

@@ -1,11 +1,11 @@
 // KT-399 Type argument inference not implemented for CALL_EXPRESSION
 
 fun <T> getSameTypeChecker(<!UNUSED_PARAMETER!>obj<!>: T) : Function1<Any,Boolean> {
-    return { (a : Any) -> a is T }
+    return { (a : Any) -> a is <!CANNOT_CHECK_FOR_ERASED!>T<!> }
 }
 
 fun box() : String {
     if(getSameTypeChecker<String>("lala")(10)) return "fail"
     if(!getSameTypeChecker<String>("mama")("lala")) return "fail"
     return "OK"
-}
+}

compiler/testData/diagnostics/tests/regressions/kt498.kt

@@ -3,5 +3,5 @@
 class IdUnavailableException() : Exception() {}
 
 fun <T : Any> T.getJavaClass() : Class<T> {
-    return <!UNCHECKED_CAST!>((this <!CAST_NEVER_SUCCEEDS!>as<!> <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>Object<!>).getClass()) as Class<T><!> // Some error here, because of Exception() used above. ?!!!
+    return <!UNCHECKED_CAST!>((this as <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>Object<!>).getClass()) as Class<T><!> // Some error here, because of Exception() used above. ?!!!
 }

compiler/testData/diagnostics/tests/regressions/kt716.kt

@@ -5,7 +5,7 @@ class TypeInfo<T>
 fun <T> typeinfo() : TypeInfo<T> = null <!CAST_NEVER_SUCCEEDS!>as<!> TypeInfo<T>
 
 fun <T> TypeInfo<T>.getJavaClass() : java.lang.Class<T> {
-    val t : <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.lang.Object<!> = this <!CAST_NEVER_SUCCEEDS!>as<!> <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.lang.Object<!>
+    val t : <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.lang.Object<!> = this as <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.lang.Object<!>
     return <!UNCHECKED_CAST!>t.getClass() as java.lang.Class<T><!> // inferred type is Object but Serializable was expected
 }
 

idea/testData/checker/ResolveToJava.kt

@@ -27,7 +27,7 @@ fun test(<warning>l</warning> : List<Int>) {
   <error>List</error><Int>
 
 
-  val <warning>o</warning> = "sdf" <warning>as</warning> <warning>Object</warning>
+  val <warning>o</warning> = "sdf" as <warning>Object</warning>
 
   try {
     // ...