Add specific warning when KClass literal expected

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -127,6 +127,7 @@ public interface Errors {
             .create(ERROR, modifierSetPosition(JetTokens.ANNOTATION_KEYWORD));
     DiagnosticFactory0<JetExpression> ANNOTATION_PARAMETER_MUST_BE_CONST = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<JetExpression> ANNOTATION_PARAMETER_MUST_BE_CLASS_LITERAL = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<JetExpression> ANNOTATION_PARAMETER_MUST_BE_KCLASS_LITERAL = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<JetExpression> ANNOTATION_PARAMETER_MUST_BE_ENUM_CONST = DiagnosticFactory0.create(ERROR);
 
     // Classes and traits

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -564,7 +564,8 @@ public class DefaultErrorMessages {
         MAP.put(ILLEGAL_ANNOTATION_KEYWORD, "''annotation'' keyword is only applicable for class");
         MAP.put(ANNOTATION_PARAMETER_MUST_BE_CONST, "An annotation parameter must be a compile-time constant");
         MAP.put(ANNOTATION_PARAMETER_MUST_BE_ENUM_CONST, "An enum annotation parameter must be a enum constant");
-        MAP.put(ANNOTATION_PARAMETER_MUST_BE_CLASS_LITERAL, "An annotation parameter must be a class literal");
+        MAP.put(ANNOTATION_PARAMETER_MUST_BE_CLASS_LITERAL, "An annotation parameter must be a `javaClass<T>()` call");
+        MAP.put(ANNOTATION_PARAMETER_MUST_BE_KCLASS_LITERAL, "An annotation parameter must be a class literal (T::class)");
 
         MAP.put(DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE, "An overriding function is not allowed to specify default values for its parameters");
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/AnnotationResolver.java

@@ -22,6 +22,7 @@ import kotlin.Function1;
 import kotlin.KotlinPackage;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor;
 import org.jetbrains.kotlin.descriptors.annotations.Annotations;
@@ -308,6 +309,9 @@ public class AnnotationResolver {
         else if (descriptor instanceof ClassDescriptor && CompileTimeConstantUtils.isJavaLangClass((ClassDescriptor) descriptor)) {
             trace.report(Errors.ANNOTATION_PARAMETER_MUST_BE_CLASS_LITERAL.on(argumentExpression));
         }
+        else if (descriptor instanceof ClassDescriptor && KotlinBuiltIns.isKClass((ClassDescriptor) descriptor)) {
+            trace.report(Errors.ANNOTATION_PARAMETER_MUST_BE_KCLASS_LITERAL.on(argumentExpression));
+        }
         else {
             trace.report(Errors.ANNOTATION_PARAMETER_MUST_BE_CONST.on(argumentExpression));
         }

compiler/testData/diagnostics/testsWithStdLib/annotations/kClass/kClassInAnnotation.kt

@@ -16,5 +16,5 @@ Ann1(<!ANNOTATION_PARAMETER_MUST_BE_CONST!><!UNRESOLVED_REFERENCE!>A3<!>::class<
 class MyClass2
 
 val x = A1::class
-Ann1(<!ANNOTATION_PARAMETER_MUST_BE_CONST!>x<!>)
+Ann1(<!ANNOTATION_PARAMETER_MUST_BE_KCLASS_LITERAL!>x<!>)
 class MyClass3