Deprecations: data class should now have at least one primary constructor parameter, parameters should be val / var and not vararg.

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

@@ -382,6 +382,10 @@ public interface Errors {
     DiagnosticFactory2<JetClassOrObject, Collection<? extends CallableMemberDescriptor>, Integer> DIFFERENT_NAMES_FOR_THE_SAME_PARAMETER_IN_SUPERTYPES =
             DiagnosticFactory2.create(WARNING, DECLARATION_NAME);
 
+    DiagnosticFactory0<PsiElement> DATA_CLASS_WITHOUT_PARAMETERS = DiagnosticFactory0.create(WARNING);
+    DiagnosticFactory0<JetParameter> DATA_CLASS_VARARG_PARAMETER = DiagnosticFactory0.create(WARNING);
+    DiagnosticFactory0<JetParameter> DATA_CLASS_NOT_PROPERTY_PARAMETER = DiagnosticFactory0.create(WARNING);
+
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
     // Errors/warnings inside code blocks

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

@@ -622,6 +622,10 @@ public class DefaultErrorMessages {
                     "Names of the parameter #{1} conflict in the following members of supertypes: ''{0}''. " +
                     "This may cause problems when calling this function with named arguments.", commaSeparated(FQ_NAMES_IN_TYPES), TO_STRING);
 
+        MAP.put(DATA_CLASS_WITHOUT_PARAMETERS, "Data class without primary constructor parameters are deprecated");
+        MAP.put(DATA_CLASS_VARARG_PARAMETER, "Primary constructor vararg parameters are deprecated for data classes");
+        MAP.put(DATA_CLASS_NOT_PROPERTY_PARAMETER, "Primary constructor parameters without val / var are deprecated for data classes");
+
         MAP.put(AMBIGUOUS_ANONYMOUS_TYPE_INFERRED, "Right-hand side has anonymous type. Please specify type explicitly", TO_STRING);
 
         MAP.put(EXTENSION_IN_CLASS_REFERENCE_NOT_ALLOWED,

compiler/frontend/src/org/jetbrains/kotlin/resolve/DataClassAnnotationChecker.kt

@@ -36,6 +36,19 @@ public class DataClassAnnotationChecker : DeclarationChecker {
             if (descriptor.getUnsubstitutedPrimaryConstructor() == null && descriptor.getConstructors().isNotEmpty()) {
                 diagnosticHolder.report(Errors.PRIMARY_CONSTRUCTOR_REQUIRED_FOR_DATA_CLASS.on(declaration.getNameIdentifier()));
             }
+            val primaryConstructor = declaration.getPrimaryConstructor()
+            val parameters = primaryConstructor?.valueParameters ?: emptyList()
+            if (parameters.isEmpty()) {
+                diagnosticHolder.report(Errors.DATA_CLASS_WITHOUT_PARAMETERS.on(declaration.nameIdentifier!!))
+            }
+            for (parameter in parameters) {
+                if (parameter.isVarArg) {
+                    diagnosticHolder.report(Errors.DATA_CLASS_VARARG_PARAMETER.on(parameter))
+                }
+                if (!parameter.hasValOrVar()) {
+                    diagnosticHolder.report(Errors.DATA_CLASS_NOT_PROPERTY_PARAMETER.on(parameter))
+                }
+            }
         }
     }
 }