Replace superFunction by baseFunctions in AST annotations and JSON AST.

libsolidity/analysis/ContractLevelChecker.cpp

@@ -290,8 +290,7 @@ bool ContractLevelChecker::checkFunctionOverride(FunctionDefinition const& _func
 		success = false;
 	}
 
-	if (!_function.annotation().superFunction)
-		_function.annotation().superFunction = &_super;
+	_function.annotation().baseFunctions.emplace(&_super);
 
 	if (_function.visibility() != _super.visibility())
 	{

libsolidity/analysis/ViewPureChecker.cpp

@@ -171,7 +171,7 @@ void ViewPureChecker::endVisit(FunctionDefinition const& _funDef)
 		!_funDef.isConstructor() &&
 		!_funDef.isFallback() &&
 		!_funDef.isReceive() &&
-		!_funDef.annotation().superFunction
+		!_funDef.overrides()
 	)
 		m_errorReporter.warning(
 			_funDef.location(),