Review suggestions

libsolidity/analysis/TypeChecker.cpp

@@ -872,12 +872,12 @@ bool TypeChecker::visit(EventDefinition const& _eventDef)
 		{
 			numIndexed++;
 			if (
-				_eventDef.sourceUnit().annotation().experimentalFeatures.count(ExperimentalFeature::ABIEncoderV2)
+				_eventDef.sourceUnit().annotation().experimentalFeatures.count(ExperimentalFeature::ABIEncoderV2) &&
-				&& dynamic_cast<ReferenceType const*>(type(*var).get())
+				dynamic_cast<ReferenceType const*>(type(*var).get())
 			)
 				m_errorReporter.typeError(
 					var->location(),
-					"Reference types cannot be indexed."
+					"Indexed reference types cannot yet be used with ABIEncoderV2."
 				);
 		}
 		if (!type(*var)->canLiveOutsideStorage())

test/libsolidity/syntaxTests/events/event_array_indexed_v2.sol

@@ -4,4 +4,4 @@ contract c {
 }
 // ----
 // Warning: (0-33): Experimental features are turned on. Do not use experimental features on live deployments.
-// TypeError: (59-65): Reference types cannot be indexed.
+// TypeError: (59-65): Indexed reference types cannot yet be used with ABIEncoderV2.

test/libsolidity/syntaxTests/events/event_nested_array_indexed_v2.sol

@@ -4,4 +4,4 @@ contract c {
 }
 // ----
 // Warning: (0-33): Experimental features are turned on. Do not use experimental features on live deployments.
-// TypeError: (59-67): Reference types cannot be indexed.
+// TypeError: (59-67): Indexed reference types cannot yet be used with ABIEncoderV2.

test/libsolidity/syntaxTests/events/event_struct_indexed_v2.sol

@@ -5,4 +5,4 @@ contract c {
 }
 // ----
 // Warning: (0-33): Experimental features are turned on. Do not use experimental features on live deployments.
-// TypeError: (85-86): Reference types cannot be indexed.
+// TypeError: (85-86): Indexed reference types cannot yet be used with ABIEncoderV2.